Monday Tuesday Wednesday Thursday Friday Saturday Sunday
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
Particle nature Atomic Mass number Skill activity Weekly quiz
of matter. structure. vs. atomic SC.912.P.8.1 SC.912.P.8.1
Difference SC.912.P.8.1 number. SC.912.P.8.2 SC.912.P.8.2
between SC.912.P.8.2 Figure out SC.912.P.8.3 SC.912.P.8.3
element & SC.912.P.8.3 number of SC.912.P.8.4 SC.912.P.8.4
compound SC.912.P.8.4 protons, SC.912.P.8.5 SC.912.P.8.5
SC.912.P.8.1 SC.912.P.8.5 neutrons. SC.912.P.8.9 SC.912.P.8.9
SC.912.P.8.2 Old Isotopes.
SC.912.P.8.3 benchmark: SC.912.P.8.1 Old Old
SC.912.P.8.4 SCA 2.4.2 SC.912.P.8.2 benchmark: benchmark:
SC.912.P.8.5 SC.912.P.8.3 SCA 2.4.2 SCA 2.4.2
SCA 2.4.2 SC.912.P.8.9
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
1 2 3 4 5 6
Modern theory Atom stability Exercises in Quiz
vs. Bohr theory due electrons. electron SC.912.P.8.1
Heisenberg Octet rule stability SC.912.P.8.2
uncertainty SC.912.P.8.1 SC.912.P.8.1 SC.912.P.8.3
principle SC.912.P.8.2 SC.912.P.8.2 SC.912.P.8.4
SC.912.P.8.1 SC.912.P.8.3 SC.912.P.8.3 SC.912.P.8.5
SC.912.P.8.2 SC.912.P.8.4 SC.912.P.8.4 SC.912.P.8.9
SC.912.P.8.3 SC.912.P.8.5 SC.912.P.8.5 Old
SC.912.P.8.4 SC.912.P.8.9 SC.912.P.8.9 Benchmark:
SC.912.P.8.5 Old Old SCA 2.4.2
SC.912.P.8.9 Benchmark: Benchmark:
Old SCA 2.4.2 SCA 2.4.2
7 8 9 10 11 12 13
Labor day Covalent Skill activities Properties of Quiz in
bonding vs. with bonding different types chemical
ionic bonding SC.912.P.8.5 of bonding bonding
Characteristics SC.912.P.8.6 between between
of the different SC.912.P.8.7 atoms atoms
types of Old SC.912.P.8.5 SC.912.P.8.5
bonding benchmark: SC.912.P.8.6 SC.912.P.8.6
SC.912.P.8.5 SCA 1.4.2 SC.912.P.8.7 SC.912.P.8.7
SC.912.P.8.6 Old Old
SC.912.P.8.7 benchmark: benchmark:
Old SCA 1.4.2 SCA 1.4.2
benchmark: . .
14 15 16 17 18 19 20
Types of Identify Examples and Exercises with Quiz
chemical chemical identification chemical Symbols and
reactions. reaction types of chemical reactions types of
Symbols, and properties reactions SC.912.P.8.7 reactions
reactants and SC.912.P.8.7 SC.912.P.8.7 SC.912.P.8.8 SC.912.P.8.7
products SC.912.P.8.8 SC.912.P.8.8 Old SC.912.P.8.8
SC.912.P.8.7 Old Old benchmark: Old
SC.912.P.8.8 benchmark: benchmark: SCA.1.4.4 benchmark:
Old SCA. 1.4.4 SCA, 1.4.4 SCA.1.4.4
21 22 23 24 25 26 27
Reactivity Factors in Enzymes . Conduction Quiz
SC.912.P.8.7 reactions activation E vs. convection SC.912.P.8.7
SC.912.P.8.8 SC.912.P.8.7 SC,912.L.18.1 SC.912.P.8.1 SC.912.P.8.8
SC,92.L.18.1 SC.912.P.8.8 Old SC.912.P.8.2 SC,912.L.18.1
Old benchmark SC,92.L.18.1 benchmark: SC.912.P.10.4 SC.912.P.10.4
SCA: 1.4.4 Old benchmark SCA. 1.4.4 Old benchmark Old benchmark
SCA: 1.4. 4 SCA:1.4.5 SCA: 1.4.4
28 29 30
Kinetic Energy Kinetic Energy Exercises with
SC.912.P.12.10 Temperature, concepts of
SC.912.P.12.11 size, nature, kinetic Energy
SC.912.P.10.5 absolute zero SC.912.P.12.10
SC.912.P.10.6 SC.912.P.12.10 SC.912.P.12.11
Old SC.912.P.12.11 SC.912.P.10.5
benchmark: SC.912.P.10.5 SC.912.P.10.6
SCB. 1.4.3 SC.912.P.10.6 Old
benchmark: SCB. 1.4.3
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
1 2 3 4
Exercises with Quiz
absolute zero. SC.912.P.12.10
between Celsius SC.912.P.10.5
and Fahrenheit SC.912.P.10.6
SC.912.P.10.5 SCB. 1.4.3
5 6 7 8 9 10 11
States of Changes in Identify Heat of fusion Quiz
matter states of matter changes and Heat of SC. 912.P.8.1
SC. 912.P.8.1 SC. 912.P.8.1 determine vaporization SC.912.P.8.2
SC.912.P.8.2 SC.912.P.8.2 state of matter SC. 912.P.8.1 SC.912.P.12.11
SC.912.P.12.11 Old benchmark: exercises SC.912.P.8.2 Old
Old SCB.1.4.3 SC. 912.P.8.1 Old benchmark: benchmark:
benchmark: SCB.1.4.6 SC.912.P.8.2 SCB.1.4.3 SCB.1.4.3
SCB.1.4.3 Old SCB.1.4.6 SCB.1.4.6
12 13 14 15 16 17 18
Radioactivity Characteristics Radioactivity Fission and Quiz
SC.912.P.10.9 of different and types of Fusion. Nuclear SC.912.P.10.9
SC.912.P.10.10 types of radiation Plants SC.912.P.10.10
SC.912.P.10.11 radiation exercises SC.912.P.10.9 SC.912.P.10.11
SC.912.P.10.12 SC.912.P.10.9 SC.912.P.10.9 SC.912.P.10.10 SC.912.P.10.12
Old SC.912.P.10.10 SC.912.P.10.10 SC.912.P.10.11 Old
benchmark: SC.912.P.10.11 SC.912.P.10.11 SC.912.P.10.12 benchmark:
SCB.1.4.6 SC.912.P.10.12 SC.912.P.10.12 Old benchmark: SCB.1.4.6
Old benchmark: Old SCB.1.4.6
19 20 21 22 23 24 25
Wave/particle Electromagnetic Characteristics Emission Quiz
Duality of Spectrum of the waves spectrum. SC.912.P.10.18.
matter explanation SC.912.P.10.18. Colors SC.912.P.10.19.
Quantum SC.912.P.10.18. SC.912.P.10.19. SC.912.P.10.18. SC.912.P.10.20
SC.912.P.10.18. SC.912.P.10.19. SC.912.P.10.20 SC.912.P.10.19. SC.912.P.10.21
SC.912.P.10.19. SC.912.P.10.20 SC.912.P.10.21 SC.912.P.10.20 SC.912.P.10.22
SC.912.P.10.20 SC.912.P.10.21 SC.912.P.10.22 SC.912.P.10.21 Old
SC.912.P.10.21 SC.912.P.10.22 Old SC.912.P.10.22 benchmark:
SC.912.P.10.22 Old benchmark: benchmark: Old benchmark: SC 1.4.1
Old SC 1.4.1 SC 1.4.1 SC 1.4.1
26 27 28 29 30 31
Teacher Potential vs. Exercises with Differentiate Quiz
planning day Kinetic Energy PE and KE between SC,912.P.10.1
SC,912.P.10.1 SC,912.P.10.1 mechanical, SC.912.P10.2
SC.912.P10.2 SC.912.P10.2 chemical…. SC.912.P.10.3
SC.912.P.10.3 SC.912.P.10.3 SC,912.P.10.1 Old benchmark
Old benchmark Old benchmark SC.912.P10.2 SCB 1.4.1
SCB 1.4.1 SCB 1.4.1 SC.912.P.10.3 SCB 1.4.7
SCB 1.4.7 SCB 1.4.7 Old benchmark
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
2 3 4 5 6 7 8
Energy Laws Exercises with Energy Characteristics Quiz
SC.912.P.10.1 energy laws transfers and SC.912.P.10.1
SC.912.P.10.2 SC.912.P.10.1 Efficiency differentiation SC.912.P.10.2
SC.912.P.10.3 SC.912.P.10.2 SC.912.P.10.1 of all type of SC.912.P.10.3
SC.912.P.10.8 SC.912.P.10.3 SC.912.P.10.2 energies SC.912.P.10.8
Old SC.912.P.10.8 SC.912.P.10.3 SC.912.P.10.1 Old
benchmark: Old SC.912.P.10.8 SC.912.P.10.2 benchmark:
SCC.2.4.6 benchmark: Old SC.912.P.10.3 SCC.2.4.6
SCC.2.4.6 benchmark: SC.912.P.10.8
9 10 11 12 13 14 15
Motion Motion graphs Veteran’s day Acceleration Quiz
Displacement SC.912.P.12.2 SC.912.P.12.2 Graphs and
Velocity vs. Old Old numerical
speed benchmark: benchmark: exercises
SC.912.P.12.2 SCC2.4.1 SCC2.4.1 SC.912.P.12.2
Old SCC1.4.1 SCC1.4.1 Old
16 17 18 19 20 21 22
Newton’s Laws Forces and Exercises with Vectors Quiz
SC.912.P.12.3 weight. forces SC.912.P.12.1 SC.912.P.12.1
SC.912.P.12.4 SC.912.P.12.3 SC.912.P.12.3 Old benchmark SC.912.P.12.3
SC.912.P.12.5 SC.912.P.12.4 SC.912.P.12.4 SCC.2.4.1 SC.912.P.12.4
SC.912.P.12.6 SC.912.P.12.5 SC.912.P.12.5 SCC.1.4.1 SC.912.P.12.5
SC.912.P.12.9 SC.912.P.12.6 SC.912.P.12.6 SC.912.P.12.6
Old benchmark SC.912.P.12.9 SC.912.P.12.9 SC.912.P.12.9
SCC.2.4.1 Old benchmark Old benchmark Old benchmark
SCC.1.4.1 SCC.2.4.1 SCC.2.4.1 SCC.2.4.1
SCC.1.4.1 SCC.1.4.1 SCC.1.4.1
23 24 25Thanksgiving 26Thanksgiving 27Thanksgiving 28 29
vs. Friction acceleration
SC.912.P.12.3 and friction
Old benchmark SC.912.P.12.9
SCC.2.4.1 Old benchmark
1 2 3 4 5 6
Earth Layers Pangaea Plate tectonics Quiz
SC.912.E.6.1 Dynamic Effect Divergent vs. SC.912.P.12.3
SC.912.E.6.2 SC. 912.6.3 convergent SC.912.P.12.4
Old benchmark SC.912.6.4 SC. 912.6.5 SC.912.P.12.5
SCD. 1.4.2 Old bench SC.912.6.6 SC.912.P.12.6
SCD. 1.4.4 mark Old benchmark SC.912.P.12.9
SCD.1.4.5 SCD. 1.4.2 SCD. 1.4.2 Old benchmark
SCD. 1.4.4 SCD. 1.4.4 SCC.2.4.1
SCD.1.4. SCD.1.4.5 SCC.1.4.1
7 8 9 10 11 12 13
Seduction Earthquakes Volcanoes Volcanoes
faults SC.912.E.6.2 SC.912.E.6.2 SC.912.E.6.2 Quiz
San Andrea SC.912.E. 6,3 SC.912.E. 6,3 SC.912.E. 6,3 Earthquake
fault SC.912.E. 6.4 SC.912.E. 6.4 SC.912.E. 6.4 and volcano
SC. 912.6.5 Old benchmark SC.912.E.6.6 SC.912.E.6.6 SC.912.E.6.2
SC.912.6.6 SCD.1.4.2 Old benchmark Old benchmark SC.912.E. 6,3
Old benchmark SCD.1.4.2 SCD.1.4.2 SC.912.E. 6.4
SCD. 1.4.2 SC.912.E.6.6
SCD. 1.4.4 Old benchmark
14 Continental 15 18 Minerals 17 18 19 20
margin Mountains and and rocks. Types of rocks Quiz
composition Plains Characteristics SC.912.E.6.2 SC.912.E.6.2
SC.912.E.6.2 SC.912.E.6.2 SC.912.E.6.2 SC.912.E. 6,3 SC.912.E. 6,3
SC.912.E. 6,3 SC.912.E. 6,3 SC.912.E. 6,3 SC.912.E. 6.4 SC.912.E. 6.4
SC.912.E. 6.4 SC.912.E. 6.4 SC.912.E. 6.4 SC.912.E.6.6 SC.912.E.6.6
SC.912.E.6.6 SC.912.E.6.6 SC.912.E.6.6 Old bench Old bench
Old bench Old bench Old bench mark: mark:
mark: SCD.1. mark: mark: SCD.1.4.3 SCD.1.4.3
4.3 SCD.1.4.3 SCD.1.4.3
21 Christmas 22 Christmas 23 Christmas 24 Christmas 25 Christmas 26 27
vacation vacation vacation vacation vacation
28 Christmas 29 Christmas 30 Christmas 31 Christmas
vacation vacation vacation vacation
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
1 Christmas 2 Christmas 3 Christmas
vacation vacation vacation
4 Christmas 5 Composition 6 7 8 9 10
vacation of Earth’s Characteristics Wind patterns Quiz
atmosphere of layers of Air pressure SC.912.E. 7.1
SC.912.E. 7.1 atmosphere SC,912.E.7.4 SC.912.E.7.2
SC.912.E.7.2 SC.912.E. 7.1 SC.912.E.7.5 SC.912.E.7.3
SC.912.E.7.3 SC.912.E.7.2 SC.912.E.7.6 SC,912.E.7.4
SC,912.E.7.4 SC.912.E.7.3 SC.912.E.7.7 SC.912.E.7.5
SC.912.E.7.5 SC,912.E.7.4 SC.912.E.7.8 SC.912.E.7.6
SC.912.E.7.6 SC.912.E.7.5 SC.912.E.7.9 SC.912.E.7.7
SC.912.E.7.7 SC.912.E.7.6 Old bench SC.912.E.7.8
SC.912.E.7.8 SC.912.E.7.7 marks: SC.912.E.7.9
SC.912.E.7.9 SC.912.E.7.8 SCD 1.4.1 Old bench
Old bench SC.912.E.7.9 SCH 3.4.2 mark:
mark: Old bench SCE 2.4.3
SCE 2.4.3 mark:
11 semester 12 semester 13 semester 14 semester 15 semester 16 17
finals finals finals finals finals
18 19 20 21 22 23 24
Weather, Weather, Clouds and climate Quiz
water cycle. water cycle. precipitation SC,912.E.7.4 SC,912.E.7.4
Precipitation Precipitation SC,912.E.7.4 SC.912.E.7.5 SC.912.E.7.5
SC,912.E.7.4 SC,912.E.7.4 SC.912.E.7.5 SC.912.E.7.6 SC.912.E.7.6
SC.912.E.7.5 SC.912.E.7.5 SC.912.E.7.6 SC.912.E.7.7 SC.912.E.7.7
SC.912.E.7.6 SC.912.E.7.6 SC.912.E.7.7 SC.912.E.7.8 SC.912.E.7.8
SC.912.E.7.7 SC.912.E.7.7 SC.912.E.7.8 SC.912.E.7.9 SC.912.E.7.
SC.912.E.7.8 SC.912.E.7.8 SC.912.E.7.9 Old bench SC.912.E. 5.3
SC.912.E.7.9 SC.912.E.7.9 Old bench marks: SC.912.E.5.4
Old bench Old bench marks: SCD.1.4.1 SC.912.E. 5.5
marks: marks: SCD.1.4.1 SCD 3.4.2 SC.912.E.5.6
SCD 1.4.1 SCD 1.4.1 SCD 3.4.2 SC.912.E. 5.7
SCH 3.4.2 SCH 3.4 SC.912.E.5.8
25 Ocean 26 27 27 29 30 31
Currents Tides Earth/Sun Earth/Sun Quiz
SC,912.E.7.4 SC,912.E.7.4 system system SC,912.E.7.4
SC.912.E.7.5 SC.912.E.7.5 Lunar eclipses Lunar eclipses SC.912.E.7.5
SC.912.E.7.6 SC.912.E.7.6 SC.912.E. 5.3 SC.912.E. 5.3 SC.912.E.7.6
SC.912.E.7.7 SC.912.E.7.7 SC.912.E.5.4 SC.912.E.5.4 SC.912.E.7.7
SC.912.E.7.8 SC.912.E.7.8 SC.912.E. 5.5 SC.912.E. 5.5 SC.912.E.7.8
SC.912.E.7.9 SC.912.E.7.9 SC.912.E.5.6 SC.912.E.5.6 SC.912.E.7.9
Old bench Old bench SC.912.E. 5.7 SC.912.E. 5.7 Old bench
marks: marks: SC.912.E.5.8 SC.912.E.5.8 marks:
SCD.1.4.1 SCD.1.4.1 Old bench Old bench SCD 1.4.1
SCD 3.4.2 SCD 3.4.2 mark; mark; SCH 3.4.2
Monday Tuesday Wednesday Thursday Friday Saturday Sunday
1 2 3 4 5 6 7
Origin of solar system. Solar system. Stellar system Comets, Quiz
Planets Planets HR diagram telescopes, SC.912.E. 5.1
SC.912.E. 5.1 SC.912.E. 5.1 Death of star Heaven bodies SC.912.E. 5.2
SC.912.E. 5.2 SC.912.E. 5.2 SC.912.E. 5.1 SC.912.E. 5.1 SC.912.E.5.3
SC.912.E.5.3 SC.912.E.5.3 SC.912.E. 5.2 SC.912.E. 5.2 SC.912.E.5.4
SC.912.E.5.4 SC.912.E.5.4 SC.912.E.5.3 SC.912.E.5.3 SC.912.E.5.5
SC.912.E.5.5 SC.912.E.5.5 SC.912.E.5.4 SC.912.E.5.4 SC.912.E.5.6
SC.912.E.5.6 SC.912.E.5.6 SC.912.E.5.5 SC.912.E.5.5 SC.912.E.5.7
Old bench mark: Old bench SC.912.E.5.6 SC.912.E.5.6 SC.912.E.5.8
SCD 2.4.1 mark: Old bench SC.912.E.5.7 SC.912.E.5.10
SCH. 3.4.2 SCD 2.4.1 mark: SC.912.E.5.8 SC.912.E.5.11
SCH. 3.4.2 SCD 2.4.1 SC.912.E.5.10 Old bench
SCH. 3.4.2 SC.912.E.5.11 marks:
Old bench SCD 2.4.1
marks: SCH. 3.4.2
8 9 10 11 12 13 14
Types of organic Types of Cell structure Movement Quiz
compounds organic and organelles across cell SC.912.L.14.1
SC.912.L.18.1 compounds SC.912.L.14.1 membrane SC.912.L.14.2
SC.912,L.18.2 SC.912.L.18.1 SC.912.L.14.2 SC.912.L.14.1 SC.912.L.14.3
SC.912.L.18.3 SC.912,L.18.2 SC.912.L.14.3 SC.912.L.14.2 SC.912.L.14.4
SC.912.18.4 SC.912.L.18.3 SC.912.L.14.4 SC.912.L.14.3 SC.912.L. 14.5
Old bench mark: SC.912.18.4 SC.912.L. 14.5 SC.912.L.14.4 Old bench
SC.F 1.4.1 Old bench Old bench SC.912.L. 14.5 mark:
mark: mark: Old bench SCF 2.4.1
SC.F 1.4.1 SCF 2.4.1 mark:
15 16 17 18 19 20 21
Energy transfer Photosynthesis Cell Quiz
Cell respiration SC.912.L.18.6 reproduction Proteins SC.912.16
SC.912.L.18.6 SC.912.L.18.7 Mitosis synthesis SC.912.18
SC.912.L.18.7 SC.912.L.18.8 SC.912.L.16.13. DNA vs. RNA
SC.912.L.18.8 SC.912.18.9 SC.912.16.14 SC.912.L.16.3.
SC.912.18.9 SC.912.18.10 SC.912.16.17 SC.912.L.16.4
SC.912.18.10 SC.912.18.11 Old SC.912.L.16.5
SC.912.18.11 Old benchmark: SC.912.L. 16.6
Old benchmark: benchmark: SCF.2.4.3 SC.912.L.16.7
SCF. 2.4.1 SCF. 2.4.1 SC.912.L.16.8
22 23 24 25 26 27 28
Genotype/Phenotype Punnet squares Ecosystems Ecosystems Quiz
Homozygous/Heterozygous SC.912.L16.1 producers vs. producers vs. SC.912.L.15.4
SC.912.L16.1 SC.912.L.16.2 consumers consumers SC.912.L.15.5
SC.912.L16.2 Old bench SC.912.L.15.4 SC.912.L.15.4 SC.912.L.15.6
SC.912.L16.3 mark: SC.912.L.15.5 SC.912.L.15.5 Old bench
SC.912.L.16.4 SCF 2.4.3 SC.912.L.15.6 SC.912.L.15.6 mark:
SC.912.L.16.5. Old bench Old bench SCG 1.4.1
SC.912.L.16.8 mark: mark:
Old bench mark: SCF 2.4.3 SCG 1.4.1 SCG 1.4.1
1 2 3. 4 5 6 7
Biomes. Food web Growth Biochemical Quiz
Populations SC.912.L.15.4 curve/population cycles SC.912.L.15.4
SC.912.L.15.4 SC.912.L.15.5 characteristics SC.912.L.15.4 SC.912.L.15.5
SC.912.L.15.5 SC.912.L.15.6 SC.912.L.15.4 SC.912.L.15.5 SC.912.L.15.6
SC.912.L.15.6 Old bench SC.912.L.15.5 SC.912.L.15.6 Old bench
Old bench mark SC.912.L.15.6 Old bench mark
mark SCG. 1.4.1 Old bench mark mark SCG. 1.4.1
SCG. 1.4.1 SCG 2.4.2 SCG. 1.4.1 SCG. 1.4.1 SCG 2.4.2
SCG 2.4.2 SCG 2.4.2 SCG 2.4.2
8 9 10 11 12 13 14
Review FCAT Review FCAT Review FCAT Review FCAT Review FCAT
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31
Nature of Matter
August 24, 2009
-Matter: anything that occupy space
-Matter is made of tiny invisible particles called ATOMS.
-The word atom means indivisible.
-Atoms of different elements are different but atoms of same element are alike.
-ELEMENT is a substance that cannot be decomposed or broken down. Examples: silver, gold, sodium...
-Different elements combine to form COMPOUNDS. Like water, table salt…
A compound and a pure substance have the same formula. For example water is a compound but is a
pure substance too.
August 25, 2009
Atoms have two basic parts of regions:
-Nucleus: it is located in the center of the atom, and it is called nucleus. The center of the nucleus is
made of protons, charged positively and neutrons with no charge.
-Outside of atom: Orbitals, with negatively charged subatomic particles called electrons. The electrons
move around the nucleus in orbitals or electron clouds. This is called the Heisenberg uncertainty
- The simplest atom, hydrogen, has only one electron in the space surrounding the nucleus.
Picture of Hydrogen atom
Picture of Nitrogen atom
There are two theories about the structure of the atom:
First theory: The atom is represented as a solar system. The sun is in the center, like the nucleus
of the atom, and the electrons are around the nucleus like the planets around the sun. This is
called Bohr’s atom theory
Second theory: The nucleus is in the center and the electrons are around but we cannot tell
specifically where the electron is located, it is sort like a fan when is moving, we cannot tell
exactly where the blades are. This is called Modern Theory
The nucleus of the atom contains most of the mass of the atom and it is positively charged (+1), so an
atom with 12 protons have a charge of +12. Neutrons have approximately the same size and mass of
protons, except neutrons do not have electrical charge.
Charges and masses of subatomic particles
Particle Mass Charge
Electron 1/1836 amu -1
Proton 1 amu +1
Neutron 1 amu 0
The masses of protons and neutrons are measured using a relative unit called atomic mass unit or amu,
which is 1/12 the mass of a carbon 12 atom.
Atoms are usually neutral, that means that have the same number of protons and electrons.
August 26, 2009
Atomic number vs. Mass number
The mass of the atomic number is the sum of the protons and neutrons, so it is called atomic
mass, measured in amu. It is represented by letter A
The atomic number is the number of the protons in the atom. It is represented by letter Z
Atoms of the same element ALWAYS have the same number of protons, but different number of
Calculating the number of protons and neutrons:
Ca-12. We look in the periodic table and see that the atomic number of the Carbon is 6, because
that is the number of protons that carbon has, so in order to find the number of neutrons, we
just subtract 12-6= 6 neutrons, this is the number of neutrons that carbon-12 has
15 N. Nitrogen has 7 protons. Then, I need to know the neutrons so: 15-7=8. The 7 is the atomic
number, 7 protons. The mass number is 15. (protons+neutrons)
Atoms of the same element can have different mass but still needs to have the same atomic
number, or it will not be the same element. Those are called isotopes. For example:
15 15 15
20P these three atoms are isotopes. They have the same atomic number but
a different atomic mass.
19P – has 15 protons, and four neutrons
20P- has 15 protons, and five neutrons
32P- has 15 protons and 7 neutrons
Many isotopes are used as tracers for medical reasons, like founding cancer in patients, other
tracers are used to find the age of a rock or a fossil.
August 27, 2009
Mass number vs. Atomic number
Using the periodic table fill the blank spaces
Element Atomic number Protons Neutrons
Using the periodic table fill the blank spaces
Element Atomic mass Mass number Protons Electrons Neutrons
August 28, 2009
Distinguish between an element and compound
What is an isotope? Describe isotope uses
Using periodic table, an atom contains 36 protons. Name the element.
List three materials in your home that are compounds and explain why are compounds.
An atom has an atomic mass of 35 and atomic number of 15. Name the element. Tell how many
protons has, how many electrons and how many neutrons.
August 31, 2009
Dalton created postulates about the atoms:
All matter is composed of small particles called atoms.
Atoms cannot be broken down into smaller particles.
Atoms of same element are alike.
Atoms can combine in simple ratios to form compounds.
Most of the statements are considered correct nowadays except one. Atoms are divisible; atoms are
composed of neutrons, protons and electrons.
September 1, 2009
The most stable atoms are those that have complete outermost electron orbitals. These
elements are called noble gases, and do not combine with other elements.
These noble gases are unreactive, that it is why they are used to protect other more reactive
materials when they are transported.
Other atoms that are not noble gases can assume the electron arrangement of noble gases by
accepting, donating or sharing electrons.
Most atoms try to obtain eight electrons in the outermost shell. This is an example of the octet
rule, which states that atoms are stable when the outermost electron shells are full.
For example: metallic elements such as sodium, lithium and calcium attain the octet electron
arrangement by giving their electrons away, forming positively charged elements called ions.
The element sodium gives up easily the outermost electron to attain the electron configuration
of a noble gas. The nonmetallic atom of chlorine will take the electron and will produce a noble
gas octet configuration.
September 2, 2009
Explain the octet rule
Give me the name of 3 noble gases. Where are they located?
What is so special about noble gases?
What is the octet rule?
When is an atom considered to be stable?
September 3, 2009
Differentiate between atom’s modern theory and Bohr’s theory
What is the principle of electron uncertainty?
Tell me, what Dalton postulate is not considered true?
Nature of Matter
September 4, 2009
Give an example of compound
What is an isotope?
Why are noble gases nonreactive?
Discuss how water molecule illustrates the octet rule
Identify location, mass and charge of subatomic particles
September 8, 2009
Atoms combine by transferring or sharing electrons to fulfill the octet rule. There are different types of
Covalent bonding; The sharing of electrons between atoms is influenced by how much attraction one
atom has for another. This type of bonding occurs between two nonmetal atoms.
We need to differentiate between
Nonpolar Covalent bonding: Occurs when there is an equal sharing of electrons between the
same atoms, as in diatomic gases like N2, O2, H2.
Polar Covalent bonding: Occurs when there is an unequal sharing of electrons. Some atoms
have greater attraction for electrons than others. For example when hydrogen shares an
electron with fluorine, the fluorine atom has a very strong pull on the electrons, and the shared
electrons is pulled closer to the fluorine, which will show slightly negative charge.
Ionic bonding: Occurs when one atom donates one or more electrons to another atom. This occurs
when a metal reacts with non metal. The metal gives up electrons to become a positive ion, and the
nonmetal accepts the electrons to become a negative ion. These positive and negative ions have noble
gas electron configurations and are attracted to each other because of their opposite electrical charges.
An atom’s tendency to gain or lose electrons when it bonds is called valence electrons. Non metal have
negative charges, which means they acquire electrons. Metals have positive charges, which mean they
September 9, 2009
Describe the bonds formed by the following elements as ionic or covalent
Discuss how a water molecule illustrates a covalent bonding
Explain shy chlorine has a tendency to gain an electron and form a covalent bond
How does an ion differ from an isotope?
Explain the differences in the bonding for the compounds carbon dioxide and sodium chloride
Properties of Covalent and Ionic substances
September 10, 2009
When elements made up of atoms combine to form a covalent compound, molecules are
Molecules are group of two or more elements held together by a covalent bond.
When elements react to form ionic substances, they assembly into molecule like units called
formula units. A formula unit is the smallest whole number ratio of one ion to another in an
Both ionic and covalent compounds have very different characteristics that the elements that
Properties of covalent and ionic substances:
COVALENT LY BONDED SUBSTANCES IONIC BONDED SUBSTANCES
Low melting point High melting point
Low boiling point High boiling point
May be gas, solid or liquid They tend to be hard crystalline solids
Poor conductor of heat and electricity Good conductors of heat and
September 11, 2009
Identify the characteristics as those of covalently bonded compounds or ionic compounds.
Low melting point___________
Poor conductor of electricity_______________
Dissolves easily in water__________________
Symbols in chemical reactions
September 14, 2009
Although words can be described the reactions of different substances, chemical equations are a much
shorter way of doing the same thing. Chemical symbols of the elements and chemical formulas are used
in chemical equations. The chemical formulas represent the names of the chemical compounds in the
reaction. The equation tells what the reacting substances are and what the products will be. The
chemical formula of each substance uses chemical symbols of the elements, and their subscripts tell
how many atoms of that element are present. The equation may also indicate the energy used in the
reaction and the physical states of the substances. The physical states of solids, gases, liquids and water
(aqueous), for example, are represented by (s), (g), (l) and (aq). The equation is balanced by placing
numbers (coefficients) in front of the chemical formula. The coefficients give the relative proportions of
the reactants and products. The reaction of chlorine gas with an aqueous solution of sodium bromide to
produce sodium chloride and bromine can be represented with the equation.
Cl2(g) + 2 NaBr(aq)→2 NaCl (aq) + Br(aq)
Types of reactions
September 15, 2009
1. Synthesis: In this type of chemical reaction, two or more elements combine to form a
compound. A more complex substance is formed from less complex substances
A + B→AB or Ca + Cl2→CaCl2
2. Decomposition reaction. In this reaction, the reactant compound breaks down into elements,
or an element and a compound, or new compounds due to strong heating.
AB→A + B or CuCO3→ CuO + CO2
3. Combustion reaction. It burns carbon containing compounds. This is easy to recognize because
one of the reactants is oxygen, and the products are carbon dioxide and water.
AB + O2→CO2 + HO2 or CH4 + O2→ CO2 + HO2
Types of reactions
1. Single displacement reaction: One element replaces another element in a compound. For this
to happen, the element replacing the original one must be at a higher level on the reactivity
series. The more active metal will replace the less active metal in a compound.
A + BC→AC +B or 2 Fe + 3 Cu(NO3)2→2Fe(NO3)3 + 3 Cu
In the reaction, iron reacts with copper (II) nitrate to form iron (III) nitrate and copper,
so iron is replacing the copper according to the tendency in reactivity series.
Reactivity Sequence of Some Common Metals
Most reactive Lithium
Less reactive Gold
2. Double displacement. Where two compounds exchange ions with each other. This type of
reaction requires that one of the products leave the solution as gas, or precipitate as a solid
AB + CD→ AD +BC or 2KOH + H2SO4→ K2SO4 +2H2O
September 17, 2009
1. In the following reaction, identify the reactants and products
Cl2 + 2 NaBr → 2 NaCl + Br2
2. Classify the reaction below as decomposition, synthesis , single displacement or double
a. 2H2 + O2 →2H2O
b. 2 Na + Cl2→ 2 NaCl
c. Cl2 + 2 NaBr → 2 NaCl + Br2
d. 2 NaCl→2 Na + Cl2
e. AgNO3 + NaI →AgI + NaNO3
1. Na(s) + OH(aq) → Na OH(s)
a. Which are the reactants?
b. Which are products?
c. What type of reaction is this?
d. What →means?
e. What is the meaning of s in a chemical equation?
f. What is the meaning of aq in a chemical equation?
2. Identify the following chemical equations as decomposition, combustion, synthesis, single
displacement or double displacement
a. CdCO3(cr)→ CdO (cr)+ CO2(g)
b. NH3+ HCl(g)→NH4Cl (cr)
c. Cl2(g) + 2KBr(aq)→ 2KCl (aq) + Br(l)
d. PbCl(cr) + Li2SO4(aq)→ PbSO4(cr)+ 2 LiCl (aq)
e. CH4 + 2O2→CO2 + 2 H2O
Factors Influencing Chemical Reactions
September 21, 2009
Factors influencing the rate of chemical reactions
There are four main of factors to consider:
1. Nature of the reactants
3. Concentration and Pressure
Nature of Reactants
There are several points to consider when we examine how the properties of the reactants
affects reaction rate.
During chemical reactions, chemical bonds are broken and new bonds are formed.
The nature (or type) of these chemical bonds - and how readily they are broken
and formed - plays a critical role in the rate of a reaction. When the reaction
involves primarily the exchange of electrons (as occurs in Redox reactions, the
topic of our last unit of study), reactions tend to be very rapid.
For example, consider this very fast double displacement reaction that involves
the formation of a yellow precipitate, barium chromate:
Ba(NO3)2(aq) + Na2CrO4(aq) → BaCrO4(s) + 2 NaNO3(aq)
We can write the net ionic equation for this reaction:
Ba2+(aq) + CrO42- → BaCrO4(s)
Reactions such as this that involve ions in solution tend to be very rapid.
As you might expect, however, if we had combined solid barium nitrate with solid
sodium chromate, the reaction would be so slow that we would not be able to
detect it. The phase of the reacting particles is important. Reactants in
solution, liquids, and gases will react much faster than solids.
Factors that influences the chemical reactions
September 22, 2009
There are many ways we can influence the rate of chemical reactions, a chemical reactant must collide
with another chemical reactant at sufficient speed for a chemical reaction to occur.
Nature of reactant: gas, solid or liquid
Pressure: In gases, pressure has a great role in the rate of the reaction. Of course, pressure is only
pertinent to gases. When the pressure of a gas is increased, the particles are closer, so they start to
collide more often, and the reaction occurs faster.
Temperature: Temperature increases the rate of the reaction, higher temperature, higher kinetic
energy, particles move faster, so more collisions are produced among them, and the reaction takes less
Surface Area: Solids can react only at exposed surfaces. One way to increase the reaction rate between
solids is to maximize the surface area where the reactants come in contact with each other. Cutting or
grinding the solid reactants into smaller and smaller particles maximizes the surface area over which the
reaction takes place. Agitation, such as stirring solids together, also increases the reaction rate between
Concentration of the solute: More concentration, more particles that can collide with each other. The
reaction occurs faster because there are more particles to collide.
Catalysts: In many instances it is not just a collision alone that starts a chemical reaction. Not all
collisions between reactants produce a reaction. It is only the effective collisions that produce the
reactions. Some chemical reactions requires surface to react, while others require that a reactant is
oriented in a particular direction. These substances that help to orient the reactants in a particular
direction, or lower the activation energy are called catalysts.
September 23, 2009
Substances called catalysts often provide a surface for a reaction to occur on, or hold a reactant in a
particular orientation so that it can have an effective collision. These catalysts speed up the reaction rate
but are not used up in the chemical reaction. Catalysts lower the activation energy, which is the
minimum energy required for the reaction to take place. For example, a reaction that would require
heating to start will take place at room temperature if catalysts are added. Adding more reactants to a
catalytic reaction will increase the reaction rate, but when all of the catalyst is saturated, the rate will
not increase even if more reactant is added. This is because most catalysts work by absorbing the
reactants onto their surfaces. Tthis
This is called surface absorption, adding more reactants have no effect.
Some catalysts catalyze biological reactions. These catalysts are called enzymes and are proteins. The
reactant is called substrate. The part of the enzyme that reacts with the substrate is called the active
enzyme. Each enzyme is specific of only one substrate. They end with the suffix –ase. For example
amylase only reacts with starch amylose. The reason for this is that the shapes of the active site and the
substrate must complement each other so that they can fit together to form a temporary association of
enzyme and substrate called enzyme-substrate complex. The formation of the enzyme substrate
complex causes a change in substrate. The result is a product without addition of energy.
Physical and Chemical Properties
September 24, 2009
Physical and Chemical Changes
Properties are characteristics that we use to identify and describe different materials.
Chemical Properties: are properties that are observable with chemical change, that is, when a
substances changes in composition. The reactivity of a substance, for example is a chemical
property that determines how it reacts with other substances what products are made. For
example: metal rusting, paper burning, wood rotten, painting….
Physical Properties: Properties that no change the chemical makeup of a substance. The
substance may change in appearance, but its chemical composition does not. . Those are
physical changes. Whether a substance is a solid, liquid or a gas, its physical state does not
change the atoms for which the substances are made. Grinding a substance into a powder form
is a physical change. A physical property has changed, but not the chemical composition.
September 25, 2009
Explain why the reaction rate of a catalytic reaction eventually becomes constant
Classify the following properties as chemical or physical
Sodium reacts with chlorine to produce sodium chloride__________
Solid sulfur is grounded____________
Butter is melted___________
Fat browns and chars when overheated__________
September 28, 2009
The kinetic theory of matter is a model used to explain the interaction of energy and matter due
to particle motion. If explains the effects of temperature and pressure on the physical states of
All matter is composed of small particles that are in constant motion. When they collide with
each other or the walls of the container, the collisions are perfectly elastic, that is, they rebound
off each other.
The velocity of particle movement is also related to mass and temperature. Larger molecules or
particles move slower, creating less number of collisions among the particles.
Kinetic Energy is the energy of motion. The kinetic energy of a particle depends on its mass and
KE= ½ mv2
Particle speed is directly related to temperature. At a particular temperature, when the
collisions are elastic, the average kinetic energy of a sample of molecules remains the same.
Increasing the temperature increases the speed and the kinetic energy of the particle. They
collide more often and harder. This also causes an increase in pressure. Conversely, the increase
in pressure will also increase the temperature of a gas.
September 29, 2009
As a substance cools, its particle movement and kinetic energy decreases. Eventually, the
particle movement will decrease until the particles do not move at all. The particles then have
zero movement, and zero kinetic energy and the temperature is absolute zero= -273 C.
The Kelvin scale starts with 0K and the unit is the Kelvin. The Celsius and the Fahrenheit scales
indicate the temperature too; but they do not indicate zero kinetic energy. On the Celsius scale
0 C= 273K. Because Kelvin and Celsius are the same size, a reading in Kelvin units can be
converted to Celsius by subtracting 273.
K= 273 + C
F=( 9/5 C) + 32
C= 5/9 (F-32)
Do a problem of each with students.
Kinetic theory math problems
September 30, 2009
Convert the temperature of the air in air-conditioned room of 20.0 C to equivalent values on the
Fahrenheit and Kelvin Temperature scales.
Kinetic Energy Graphs
October 1, 2009
As can be seen in the graph above, as we move from left to right, the temperature of
liquid water increases as energy (heat) is introduced. At 100ºC, water begins to undergo
a phase transition and the temperature remains constant even as energy is added (the
flat part of the graph). The energy that is introduced during this period goes toward
breaking intermolecular forces so that individual water molecules can “escape” into the
gas state. Finally, once the transition is complete, if further energy is added to the
system, the heat of the gaseous water, or steam, will increase.
This same process can be seen in reverse if we simply look at the graph above starting on
the right side and moving left. As steam is cooled, the movement of gaseous water
molecules and thus temperature will decrease. When the gas reaches 100ºC, more
energy will be lost from the system as the attractive forces between molecules reform;
however the temperature remains constant during the transition (the flat part of the
graph). Finally, when condensation is complete, the temperature of the liquid will begin to
fall as energy is withdrawn.
Phase transitions are an important part of the world around us. For example, the energy
withdrawn when perspiration evaporates from the surface of your skin allows your body to
correctly regulate its temperature during hot days. Phase transitions play an important
part in geology, influencing mineral formation and possibly even earthquakes. And who
can ignore the phase transition that occurs at about -3ºC, when cream, perhaps with a
few strawberries or chocolate chunks, begins to form solid ice cream.
Now we understand what is happening in a pot of boiling water. The energy (heat)
introduced at the bottom of the pot causes a localized phase transition of liquid water to
the gaseous state. Because gases are less dense than liquids, these localized phase
transitions form pockets (or bubbles) of gas, which rise to the surface of the pot and
burst. But nature is often more magical than our imaginations. Despite all that we know
about the states of matter and phase transitions, we still cannot predict where the
individual bubbles will form in a pot of boiling water.
October 2, 2009
A liquid has been subjected to temperatures ranging from 95 C to almost absolute zero. Predict
and describe the particle movement within the liquid as temperature decreases.
Use the phase change and explain phase changes with increase of temperature with kinetic
What is the boiling point of water in Kelvin?
States of matter
October 5, 2009
States of Matter
Matter exists in four states: solid, liquid, gas and plasma.
Solids have definite shape and volume. Atoms are limited in movement. The particles are very
close to each other and they are vibrating constantly. When heat is added these particles
vibrate more rapidly, passing the increased vibration along to other particles by colliding with
them. For example this vibrational heat energy passes through a metal rod. This is called
thermal or heat conduction.
This vibration makes metals expand with heat, for example this needs to be considered by
architects when design a building or a bridge. This phenomenon is called thermal expansion.
The removal of heat energy from the metal rod by cooling will shrink back to the original size.
The main factors to consider in thermal expansion are the nature of the material and the
When particles of a solid get far enough apart, they are capable of moving away from the rest of
the solid material to form a liquid. This process is called melting. To be able to move far enough
and fast enough, the particles must absorb energy to break the attraction the solid particles
have for each other. This extra heat energy is called latent heat of fusion.
Sublimation- Change of solid to gas directly.
States of Matter
October 6, 2009
As a liquid, particles can now vibrate and rotate around each other, with a limited ability
to travel short distances from each other. Liquid particles have less of an attraction for one
another than solid particles do, since they are farther apart. Particles of liquids can flow from
one place to another and fill a container they are in. Particles of a liquid do the same that
particles of a solid, they move faster when heat is added. They collide with the walls of the
container and each other, producing pressure. As the particles move faster, the space between
them increases. This increases the volume of the liquid. This increase of volume is comparable
to the thermal expansion in solids.
The particles of a liquid are in constant motion, vibrating, rotating and moving from place to
place. As happen with the solids, the particles of liquids still attract to each other. This limits
the distance and location where the liquid particles can move without running into each other. If
enough heat energy is added, the attractive forces break, allowing the liquid particles to move
apart from each other and break through surface of liquid.
The liquid particles have to gain considerable speed to move away from the liquid surface by
them. Once they do, they become a gas. The change of a liquid into a gas is called evaporization
or vaporization. The amount of energy required to vaporize a liquid without a change in
temperature is called the heat of vaporization.
October 7, 2009
Gas particles vibrate, rotate and move from place to place. As a gas, the particles are now
moving from place to place very fast. When they collide with each other or strike the walls of
the container, they exert a force. This force is what is called pressure
As particles move faster and faster, they impact greater pressure when they strike the wall. The
speed of the gas particles is dependent upon the absolute temperature. Hotter gases move
faster than cooler gases.
The phase change curve or heating curve shows what happens to the temperature when a very
cold solid is gradually heated at a constant rate. During the time the substance is a solid, the
temperature increases at a constant rate. During the phase change, in this case, melting, the
temperature remains the same while heat is still being added to the system. While all of the
solid melts, the liquid’s temperature increases at a constant rate. During boiling, again the
temperature remains the same until all of the liquid is converted to gas. The temperature of the
gas then continues to rise at a constant rate.
A cooling curve, where heat is removed at a constant rate, shows the same characteristic
features as the boiling point and melting point, where the temperature remains constant during
the phase change.
Plasma is a state of matter in which electrons and atomic nuclei behave like particles and are
independent of each other. Although the overall electric charge of plasma is zero, it conducts
October 12, 2009
Radiation is the release of subatomic particles and energy form the nuclei of unstable atoms.
The atoms are dumping mass, energy or both to attain a stable nucleus. Atomic nuclei with even
number of protons and neutrons tend to be more stable that those with odd numbers.
Three basic types of radiation:
Alpha- α- Produce alpha particles. An alpha particle consists of two protons and two neutrons,
which is also the nucleus of a helium atom. The alpha particle lacks electrons and has a charge of
+2. When the neutrons and protons are released as alpha particles, the atomic and mass
numbers change and a new element is produced
Beta-β- are high speed electrons generated from the decaying nucleus of an atom. This type of
radiation is called beta decay. Beta particles have little mass and a charge of -1. The electron
produced is not one of the original electrons orbiting outside the nucleus. The source of the
beta particle is a neutron which changes into a proton and electron. The atoms has now become
the atom of another element and it is during this process of change that the beta particle has
γ gamma- They are high energy photons or packages of electromagnetic energy. Gamma
radiation only releases energy and does not affect atom.
October 13, 2009
Alpha particles are emitted in alpha decay.
The parent nucleus is usually a heavy element.
For example, polonium-214 decays by alpha decay to lead-210 and an alpha particle:
84Po 82Pb + 2He
Notice that this nuclear equation is balanced in both the proton number (84 = 82 + 2) and the
nucleon number (214 = 210 + 4).
Ra→222Rn + ?
Beta particles are emitted in beta decay.
The parent nucleus is usually an isotope with an excessive number of neutrons.
For example, carbon-14 decays by beta decay to nitrogen-14 and a beta particle:
6C 7N + -1e (beta with Q = -e)
This equation is balanced in the charge number (6 = 7 + (-1)) and nucleon number (14 = 14 + 0).
Z increases by one, and N decreases by one.
Gamma decay occurs when a nucleus emits a gamma particle, a high-energy photon.
This only occurs when a nucleus has extra energy, perhaps because it was just created in a
previous nuclear decay.
An example of gamma emission is barium-137m, which is a nucleus of Ba which has just been
created in a beta decay of Cs-137:
55Cs 56Ba* + -1 While it is possible to predict the percentage of atoms e (a beta decay)
56Ba* 56Ba + g (a gamma decay)
October 14, 2009
Half-life is the time required for half of the atoms of a radioactive isotope to undergo decay. Some
isotopes are very stable, undergo decay very slowly, and have extremely long half-lives. Uranium-238
has a half-life of 4.46 billion years! Other isotopes are extremely unstable, and have short half-lives. The
isotope francium-233 has a half-life of 22 minutes. That means that if you possessed 10 grams of
francium-233, after only 22 minutes you would have 5 grams of francium-233, while the remainder of the
atoms would have been converted by some decay processes to other elements.
Radium -226 has a half a life of 1599 years. How long will it take 7/8 of a radium-226 sample to
First- Subtract a whole life from 7/8 that decay 1- 7/8= 1/8
Second- Calculate the number of half lives ½ x ½ x ½ = 1/8
Third- There are 3 half lives.
Four- 1599 x3 = 4797 years
Now let’s do one problem together;
Problem: Calculate the time required for ¾ of a sample Cesium-138 to decay, given that half a
life is 32 minutes.
Nuclear Fission and Fusion
The nuclei of very large atoms have the potential to split or fission into smaller nuclei. During
this process, a small quantity of mass will be lost and converted into energy, as predicted by
Einstein equation. E= mc2. Usually, the fission process begins with the adsorption of a low
energy neutron by the U-235 nucleus, producing a more stable uranium-236 nucleus. This
nucleus will split apart, producing heat, gamma rays, two or three neutrons and two fission
products, for example krypton 92 and barium 141. The energy is released in the form of heat
and light. There is a loss of fraction of an amu during the reaction. Notice the neutrons are both
products and reactants in this reaction as shown below:
U + 1n → 236U→92Kr + 141Ba + 3 1n + γ + energy
In the reaction above, a uranium isotope, 238U. absorbs a low energy neutron forming 236U,
which fissions into two lighter nuclei (Kr and Ba), three neutrons, gamma ray, and heat energy.
In a nuclear reactor or in an atomic bomb, these neutrons are the means to carry out a
chain reaction. In a chain reaction, the neutrons produced will collide with more nuclei and
release more neutrons and energy. The collisions will continue to increase, releasing more and
more neutrons and energy. In an atomic bomb, the neutrons are encouraged to split more and
more atoms at a faster and faster rate. In a nuclear reactor, however, the neutrons are slowed
and absorbed to control the reaction rate at a low level for a long time.
Nuclear fusion is another way atoms can interact and release nuclear energy. In this process,
the nuclei of small atoms combine with each other to produce larger, heavier atoms. The most
common example is stellar fusion, where stars fuse hydrogen atoms to produce helium atoms.
During this process, a tremendous amount of energy is released and a small amount of matter
disappears. This is predicted by E= mc2. The mass that disappears, mass defect, is converted
into energy in form of light and heat. Fusion reactions require extreme temperatures and
pressure to overcome the repulsion of particles with the same positive charge. Providing these
conditions in an appropriate environment has proved the most difficult task in the design and
construction of nuclear fusion reactor.
Problems with nuclear reactors.
May be dangerous if a radioactive escape happens.
High cost to build
Need to find a place to keep radioactive garbage. Half lives are very big like thousands of years
The average of a nuclear plant is about 40 years.
October 16, 2009
What are the compositions, masses and charges of alpha, beta and gamma radiation?
Why does the mass number of an atom remain the same during beta decay?
Compare nuclear fission and nuclear fusion
Duality of Matter
October 19, 2009
Wave/Particle Duality of Matter
As scientists learn more about atoms, they realize that there is less distinction between matter
and energy. Radiant energy and particles have the same properties. Small particles behave like
waves, and waves behave like particles. Nielhs Bohr discovered that atoms gave off or emitted
light energy in only discrete packages called quantum of energy. The spectroscope is a device
used to expand and separate out patterns of radiant energy called spectrum.
Quanta of radiant energy are often called photons. Planck stated that the amount of energy
given off is directly related to the frequency of the light emitted. Planck’s idea was that one
quantum of energy was related to the frequency E= hν, where h is a constant. The constant is
known as Planck’s constant. Its value is 6.6260755 x10-34 joules /hertz. ν is frequency
Einstein found that an atom would absorb only specific quanta of light energy when an electron
was removed from the atom. For the electron to return that same quantum of light, energy
must be released. An absorption spectrum is a spectrum observed when light energy is
absorbed by gas, and the radiant energy is absorbed by the outermost electrons of the atoms.
The energy for each electron transition can be calculated using Plancks equation E= hν. Electrons
in atoms can have the properties of both waves and particles. They give off and absorb only
specific amounts of radiant energy; indicating that electrons have distinctive energies.
October 20, 2009
When most people think of light they think of sunlight or the colors of the rainbow which is
visible light. But this is a very small part of the whole spectrum of light which is called the
electromagnetic spectrum. This spectrum of different wavelengths goes from the very shortest
known as gamma rays to the longest which are called radio waves.
The different types of light waves found in the electromagnetic spectrum going from the
smallest to the largest are: gamma rays, X-rays, ultraviolet rays, visible rays, infrared rays,
microwave rays, and radio wave rays
A gamma ray is light with the most energy. Gamma rays come from exploding stars as well as
unstable radioactive elements. X-rays are high-energy waves produced in intense environments
such as exploding stars or the accelerated particles from an X-ray machine. Ultraviolet rays are
waves that still have a lot of energy. They are emitted from extremely hot objects. These are the
rays that give you sunburn when you stay out in the sunshine too long. Visible rays are the light
that we can see with our eyes. Infrared rays are sometimes thought as heat waves but in reality
they are on the lower energy side of the electromagnetic spectrum. Microware rays are
sometimes called high energy radio waves. Radio waves have the lowest amount of energy due
to their extremely long wavelengths. These waves are produced when electrons twist around
Everything in the universe gives off light in one form or another. What the object is made
off, its temperature, and its magnetic fields determine what type of light will be emitted.
For example, microwaves found in space are given off by giant molecular clouds with
temperatures as low as 73 K which is a minus 200 degrees Celsius or a negative 392
degrees Fahrenheit. Stars that are not very bright in the visible light may shine very
brightly in infrared, ultraviolet, or X-ray light. All these light sources however, are invisible
to the human eye and we need instruments to detect them.
As stated, every object, every element, every atom, everything emits light that is unique to that
object. This is referred to as the spectral signature of that element or compound. Knowing this
then, by making a spectral analysis, or analyzing the light given off by objects or stars, we can
tell what they are made of and what the temperatures of the objects are.
October 21, 2009
●Electromagnetic waves can be measured by their wavelength and frequency.
●The wavelength is λ and it is the distance between two waves peaks.
● the frequency is represented as ν and it is the number of waves that pass through a point in
one second. It is measured in Hertz or cycles/s
●The velocity of the wave c is the speed of light for all electromagnetic waves. The properties of
the waves are related to each other by the equation c= λν
● the amplitude of the wave is the maximum displacement from zero.
October 22, 2009
Light is made of different colors. Each color has a different wavelength and frequency. We see
color when wavelengths of light are reflected, but when wavelengths are shorter than those of
violet light or longer than those of red light, they are not visible to the human eye.
When an atom becomes excited, its energy level is raised and its electrons move from lower
energy level, or ground state, to a higher energy level. To do this, only a discrete amount of
energy is absorbed by the atom. When an energized atom returns to its lowest energy level or
ground state it must give off energy. It will be a discrete amount of electromagnetic energy
represented by one or more colored lines. This is called an emission spectrum. Each colored or
bright line represents a specific amount of energy. Max Planck concluded that atoms give off
energy in discrete packages called quanta.
Consider the diagram below in order to answer questions #1-2.
1. The wavelength of the wave in the diagram above is given by letter ______.
2. The amplitude of the wave in the diagram above is given by letter _____.
3. Indicate the interval which represents one full wavelength.
Describe the colors of the visible spectrum from the lowest to highest wavelength
Explain what happens when electrons of an excited atom drop to a lower energy level
Potential vs. Kinetic Energy
Energy is defined as the ability to do work. Energy comes in two different states: Potential and
Potential Energy is stored energy. The stored energy might be in the position of an object
above a specific point, or it may be in the chemical composition of the object or a substance. For
example, the potential energy of gasoline is stored within the chemical bonds or hydrocarbon
molecules. The energy will be released when the gasoline reacts with oxygen. Water behind a
dam also has a state of potential energy due to its ability to fall to a lower level. The food we
eat is also potential energy; it is released when the food substances react with oxygen. Several
different forms of energy may be released when stored potential energy is converted to other
forms of energy. For example, when an atomic nucleus is split apart, nuclear energy, heat
energy and light energy are released.
Kinetic Energy is the energy of the motion. Kinetic energy is most often seen as the molecular or
atomic motions of the particles of matter. This constant motion shows up as the absolute
temperature of the matter. It is directly related to the average kinetic energy of the particles.
The Kelvin temperature scale is used to measure absolute temperature. Absolute zero or 0 K is
where molecule vibration stops.
KE= ½ mv2
Kinetic vs. Potential Energy Exercises
Find the Kinetic Energy of a car with a velocity of 70 Km/h and a mass of 1250 kg. Remember
Find the Potential Energy of a 3 kg rock on a 15 m cliff.
Types of Energy
October 29, 2009
Energy occurs in many forms. One form of energy, heat energy is produced by the movement of
atoms, ions, and molecules.
Heat is thermal energy. Thermal or heat energy is released when atomic or molecular
movements speed up. Sources of h eat include the simple friction produced by rubbing objects
against each other; the heat released from nuclear reactors, or the heat of your body.
Mechanical Energy is energy use by moving machinery or objects doing work. The engine of a
car moves many different parts such as gears, wheels and axles that ultimately move the car. A
moving metal block does work when it deforms the object it collides with. Sound energy is also a
mechanical energy because air molecules move back and forth.
Electrical Energy is produced by the movement of electrons. Motor driven appliances, for
example, vacuum cleaners, are operated with electrical energy. Electric lights, heaters, and
computers also use electrical energy because electrons are driven through their conductors.
Chemical Energy is energy that is stored in the chemical bonds of food, fuel or natural gas. This
energy is released by chemical reactions that usually produce other forms of energy including
heat, light, and electric current and motion.
Radiant or Light Energy is a form of electromagnetic radiation travelling as waves. Light energy
can pass through transparent materials, reflect off shiny surfaces, or be absorbed and converted
into heat or electrical energy. Light energy is a form of electromagnetic radiation. Light velocity
is 3.0 x108m/s
Different forms of Energy
Energy Form Example
Nuclear Nuclear reactor
Types of Energy
October 30, 2009
Give two examples of potential energy and two examples of kinetic energy
Explain how potential and kinetic energy differ
Distinguish between heat and temperature
Describe the energy transformations when you strike a match
Describe the types of energy generated when you h it a nail with a hammer
You throw a rock as high as possible
What happens to the kinetic energy when the rock goes higher and higher?
What happens to the potential energy of the rock when gets higher and higher?
When the rock reaches the highest point and begins to fall, what happens to the potential
energy? What happens to the kinetic?
November 2, 2009
The Law of Conservation of Energy (also known as first law of thermodynamics) states that the
energy can be neither created nor destroyed but can transform from one form to another. This
means that the total amount of energy leaving the system is equal to the total amount of energy
entering the system. For example, a plant transforms energy of the sun by converting light
energy from the sun into a chemical form of energy. Light bulb convents electricity into light
energy and thermal energy. This law is a subtle way of stating that, when heat is added to the
system, a small amount remains within the system while the remainder leaves.
The Law of Conservation of Mass (also known as the law of conservation of matter) states that
matter cannot be either created or destroyed. The chemical or physical forms can change but it
is not created nor destroyed. Because both energy and matter cannot be created or destroyed,
the two laws are often combined into one and called the Law of Conservation of Energy and
Second Law of Thermodynamics. It deals with the direction of thermal processes. Heat can
flow only from hot to cold, a downhill process. In other words, energy only flows one way.
Systems tend to go from a state of high energy to a state of low energy, and that is why heat
cannot ever go from cold to hot. Heat engines with 100 percent energy efficiency are
impossibility because all the heat from the engine’s energy source can never be completely
converted into work due to losses of waste heat. Energy capable of doing useful work must be
concentrated and as it is used, it changes to more diluted energy. For example, some of the
chemical energy of gasoline changes into mechanical energy moving parts of the engine,
warming the engine parts, and creating frictional heat. The energy leaves the engine as an ever
expanding hot gas, losing heat as expands. At every step of all energy transformations, energy is
lost and converted into unusable forms. This spreading and dilution is called entropy.
November 3, 2009
Entropy is a state of disorder. Increasing entropy increases disorder of the surroundings. As time
passes, entropy increases. Any process that increases entropy is a favored process in nature. The
only way to slow or keep entropy temporarily in check is to create even more entropy and
expend energy. The combustion or burning of sugar is a good example of entropy. A molecule of
sugar with high energy content is converted into heat and molecules of carbon dioxide and
water when it is burned. Starting with one molecule and ending with more molecules, increases
entropy, and spreading the heat energy among the products further increases the disorder or
randomness of the system. The change in entropy can be shown in the formula
Where the change in entropy is Δs is equal to the heat energy Q divided by T in kelvins.
This second law of energy determines what we can and can’t do. It is entropy what makes
perpetual motion machines impossible. It is entropy that determines energy efficiency in
machines and biological processes. There is no known process where entropy decreases.
Energy transformations are not 100% efficient. Whenever energy is changed from one form to
another, there is an energy loss in the transformation. Most often, the energy is transformed
into heat or other unwanted forms of energy.
For example, although we get the desired radiant energy of light in the form of visible
electromagnetic radiation when we turn on a light bulb, we also get unwanted heat energy in
the form of infrared radiation. On the other hand, when we burn fuel to obtain heat, light is a
byproduct. When we use mechanical energy, friction is converted to heat, and went we use
electrical energy, resistance converts to heat (resistance is electrical friction)
Energy efficiency is the percentage of energy used to accomplish a task. Efficiency is another
way to look at the amount of energy lost in systems. Optimally tuned mechanical systems can
attain an efficiency of about 37 %. That means that 63% is lost in heat. The automobile has poor
efficiency. Only 8 % reaches the wheels.
In all living things, energy is required to build tissues and carry out other life processes. Plants
use energy from the sun to produce food molecules. Animals convert food energy to mechanical
energy for movement, breathing, and other functions. In all these energy transfers, energy is
lost as waste heat that flows into the environment.
Why is it impossible to design a perpetual motion machine?
What does the first law of energy tell us about the total amount of energy in the universe?
Give three examples of energy conversion in your daily life
What is entropy?
People often say we live in a throwaway society. Explain how this could be fixed, and dispose of
these used unwanted materials.
What are the advantages of using energy efficient appliances?
How can you save energy at home?
November 5, 2009
Prior 1900’s, people depended on wood as their primary energy resource. After the 1900’s
people switched to coal, natural gas and oil. Eventually, oil became the energy resource with the
most widespread us. Because of economical, political, and environmental problems, the United
States has been trying to lower its energy consumption by the development and use of
alternative energy resources.
The main advantage of solar energy is that it is plentiful, cheap and be nonpolluting. There are
several different ways to harness solar energy for use. Primary methods convert sunlight directly
into heat energy. Although this is highly effective for heating water, homes and other buildings
in many parts of the world, there are places close to the polar regions where little solar energy is
available, and the temperature differences a solar heater to have to overcome are too great.
Other places where sunlight is limited by clouds or mountain barriers also have limited available
The direct conversion of solar energy to electricity was too expensive even a few years ago.
Now, new types of solar cells, which cost less and are more efficient, are beginning to be used in
houses and demonstration buildings. Another problem is that they do not produce the large
amounts of electric current that are required by many of today’s appliances and applications.
One of the biggest problems with solar energy is nighttime. When the sun goes down, the
energy source is gone too. Methods to store the energy produced in the daytime for use at night
include the use of batteries of hydrogen generation from electrolysis (breakdown) or water.
Another problem with solar energy is that is concentration is limited. Only a finite amount of
sunlight falls in a given area. This energy cannot be stored or amplified. Large areas of the
surface of the earth would have to be covered with solar collectors to produce large amounts of
Another form of solar energy is wind energy. Winds are created when different parts of the
Earth heat and cool at different rates, creating air flows. In some parts of the country “wind
farms” using large windmills are very effective in producing electricity, although constant winds
cannot be guaranteed. The sites where these windmills can be located are limited by the wind
potential of the sites and the availability of land on which to build the windmills. As is the case
for sunlight, the energy available for wind generation of electricity is also limited by its random
In some parts of the world, volcanic activity occurs near the surface of the Earth and there is
also a water supply to make steam. These conditions create an attractive energy source.
Geothermal power generation is the largest alternative power generation in the U.S.It has been
used around the world since the early 1900’s for electrical generation, and since recorded
history for hot water sources. It is used in fifteen countries today. AS is the case with any
technology, it has taken time for the problems associated with it to be worked out.
Geothermal energy takes the steam from underground sources and uses it to directly run steam
turbines. The steam turbines turn electrical generators or use the hot steam to heat water and
make more steam to run the plant. Today, waste steam and gases are injected back into the
ground for reheating.
The major advantage of geothermal power is that it can replace fossil fuels as a high energy
efficiency resource in electricity production for both home and industry. It does not burn
anything, so there are no sources and is economically competitive and can supply power for a
The disadvantages are that it can be depleted if used too rapidly and it is restricted to specific
areas of the U. S. such as California, the Northwest and Hawaii. Florida is not one of the states
with geothermal resources.
Nuclear fission is released from the nucleus of an atom by two major processes. Atoms with very
large, heavy nuclei undergo a process called nuclear fission, in which a large nucleus splits into
two lighter nuclei releasing heat, light and radiation. Nuclei with less mass release less energy
when they fission and are less likely to fission.
Nuclear fission technology has been growing steadily ever since WWII when it was first used to
make atomic bombs. The nuclear reactor uses the fissioning of uranium 235 to produce heat,
which is then used to generate steam to run turbines and generators for electricity production.
It is the high energy potential of the reactor that makes it attractive for power generation.
The major advantage is that nuclear reactors require no fossil fuels. They produce no
greenhouse gases, and nuclear power is a known technology. Reactors have their own fuel cycle
where natural uranium U 238 is enriched with the fissionable U 235. Neutrons released in the
nuclear reactor can turn some of the U 238 into plutonium. Plutonium will also fission and is one
of the major components of atomic bombs.
The neutrons from the reactor make the reactor, its fuel rods, the coolant, and all those close
parts radioactive. Man of these components will be radioactive long after the power plant no
longer operates. One major problem that we are facing today is what to do with all of the odd
reactors and spent fuel rods. Nuclear disasters at Three Mile Island and Chernobyl have also
shown the potential and real risks of living with nuclear technology. Public support of nuclear
fission technology, already low, will probable is even less in future.
Our supply of Uranium nuclear fuel and fossil fuel, too, will some day run out and we will have
to convert to other types of nuclear fuel, such as plutonium or retire this type of energy
Nuclear energy is released when very light atoms are forced together under extremely high
temperatures and pressure. For example, hydrogen and helium have low atomic weights and
their nuclei will combine or fuse under extremely high temperatures and pressures. Nuclear
fusion also produces heat, light and radiation. Hydrogen is fused into helium in the sun and
other stars. On Earth, the conditions for nuclear fusion are difficult to produce. This is the power
source for the hydrogen bomb.
For many years, nuclear fusion technology has been expected to replace fission reactors. Getting
a workable fusion reactor has not been an easy task. Trying to get two protons to hit each other
hard enough and fast enough to produce helium is difficult. The temperatures required are
those similar to the sun temperatures. Any material that comes in contact with those
temperatures vaporizes. Strong magnetic fields are used to confine or squeeze the hot gases
into the temperatures and distances needed to react. We have been successful in producing
fusion reactions, but not the long running, continuous reaction we need.
One major drawback of nuclear fusion is its cost. This is because the technology has to be
invented as we go. As with fission, there are radioactivity and waste materials to deal with in
fusion as well. The major advantage of fusion however is the vast amount of potential fuel that
we have and the large amounts of energy that could be produced.
Because they do not produce greenhouse gases, neither nuclear fission nor nuclear fusion
contributes to global warming. However, both do produce vast quantities of waste heat, which
ultimately ends up in Earth’s atmosphere.
Hydroelectrically Power is electrical power produced from huge dams or waterfalls.
Hydroelectric power is dependent on both geology and climate. Dams built across rivers and
lakes to produce water reservoirs are dependent on rainfall in the area. They also need a large
vertical drop to provide enough potential energy in the form of stored water. It is this water
falling into waterwheels or turbine blades that turns electrical generators. Once built, dams
offer a nonpolluting source of cheap electricity. Today, the operation of dams to provide day to
day electrical needs is dwarfed by the demand of electricity. Hydropower is now used as a peak
load source when the demand for electricity’s at its highs. This is to conserve the limited
quantity of water behind the dam.
In years with less rainfall or snowfall hydroelectric dams must conserve as much of their water
as possible. Over the long term, dams gradually tend to fill up with silt and mud and become
useless. Since, in this country, all useful rivers have been dammed, hydroelectric power is
limited to those dams that have already been built. There are no plans to build new dams in the
Natural gas, oil, and coal are fossil fuels. Fossil fuels were formed by the decay of plants and
animals millions of years ago. Over time, pressure and intense heat caused the organic materials
of these plants and animals to form energy deposit of oils, gas and coal.
We burn fossil fuels to generate heat. We use the heat to produce warmth, create electric
power, and run our cars and other engines. Fossil fuels are versatile in the ways we can use
them or refine them in another forms.
Two major factors have to be considered in the use of fossil fuels. First, fossil fuels are
nonrenewable resources because they cannot be recycled or regenerated once they are used.
We are quickly running out of them, once they are gone, they are gone forever. Today we are
dependent on foreign sources of oil to keep running our society. In 25 or 50 years, we have
used them all, and we will have to find other energy sources. In the meantime we are looking
for oil reservoirs in the U.S and offshore waters over the continental shelf. Controversial debates
are going right now over whether to allow new oil and gas exploration in the Arctic National
Burning fossil fuels also produces the greenhouse gas carbon dioxide. Raising the levels of
carbon dioxide have increased the atmospheric temperatures and contributed to global
warming. Sulfur oxides react with water in the atmosphere and produce acid rain. Acid rain is an
atmospheric mixture of acidic substances and acid forming compounds that fall to the ground.
Acid rain has destroyed lakes and forests, and caused damage to buildings and metal fixtures. It
also caused health problems by contributing to asthma and other human respiratory diseases.
Explain why the United States should become less dependent on fossil fuels as an energy source.
What is a renewable source? What is a nonrenewable source?
List 3 renewable sources, and 3 nonrenewable sources
Explain why there are no plans to build hydroelectric dams
Describe the environmental impacts of acid rain
November 9, 2009
To measure motion, we need reference points. We can measure an object’s displacement, or
the distance that it traveled from the reference point. We can also easily measure the time it
took for the object to travel that distance from the reference point. Using a reference point, we
can also determine the direction of the movement of the object. Motion that can be described
as a displacement from an original position to a new position.
The distance can be determined by subtracting of the original position from the new position.
This distance is the change in position. It tells us how far the object has moved. If we know the
time that has elapsed for the object to move from the original location to the new one, we can
divide the distance by the time and get the velocity. That is
Where s is velocity, Δs is change in distance and Δt change in time
Therefore velocity is the change in distance per unit of time. Velocity is a vector quantity, which
includes direction of motion, while speed is only distance per unit of time, does not include
direction. All motion is relative to the frame of reference. Sometimes our frame of reference
may be moving as well. Even now we are moving throughout space in our orbit around the sun,
which is moving around our galaxy. Earth is rotating on its axis. There is not an absolute frame of
reference in describing motion. When objects move at or near light velocity, the frame of
reference becomes very important. The velocity of light must always be the same for any
observer in a moving system or to an observer in a stationary system.
Find the velocity of a car that has driving 134 km in about two hours. Find the velocity in Km per
hour and meter per second.
A distance graph indicates how far an object has moved with time:
-The steeper of the line, the faster of the motion
- A horizontal line means that the object is not changing its position, it is at rest.
- A downward line means that the object is returning to the original position
Find the velocity in 6 seconds and in 8 s
Motion / Acceleration
November 12, 2009
Any change in velocity is called acceleration. Acceleration is defined as the rate of change of
velocity. Falling objects accelerate as they fall towards the ground. This is expressed by the
Where a is acceleration, Δv change in velocity and Δt= change in time.
Acceleration can be positive and negative, positive if it is going faster and negative if it is slowing
-Find the acceleration of a moving comet from 242m/s to 365 m/s in about 5 s.
) Describe the motion.
b) What is the distance travelled during the motion?
c) What is the average speed for the motion?
November 13, 2009
Find the velocity of the object after 3 seconds of travelling
Find the acceleration from rest to 8 seconds.
What has happen to the object during the horizontal line?
Newton Forces of Motion
November 16, 2009
The study of motion and forces is called mechanics. Forces, meaning a push or a pull on an
object, nay cause motion or alter motion. Gravity for example is a force we deal with every day.
It is an attractive force or a pull that Earth and an object have for each other. The force of
gravity makes it difficult to make massive objects move.
1st Law of Motion
Isaac Newton described the basic assumptions of force and motion
Newton’s first law of motion states: An object at rest tends to remain at rest. This property is
called inertia. The more mass an object has, or the more that weighs, the more inertia it has.
Inertia is not just a resistance to motion; it also describes how objects resist to changes in
movement once put into motion. An object in motion tends to remain in motion; an object at
rest tends to remain at rest.
To make an object change its motion or travel in a circular path requires a force. An object orbit
around Earth is attracted toward Earth by Earth’s gravitational pull. If we could switch off
gravity, the orbiting object would move off in a straight line at a constant speed.
An object travelling in a straight line at a constant speed requires force acting on it to make it
change speed or direction. If the force is applied to the right then the object will move to the
right, following curved path. If the force is applied in the opposite direction, the object will veer
to the left. Force acting in the opposite direction of the motion will slow down the object. If the
force is in the same direction of the motion will increase the velocity of the object. An object
travelling in a straight line at a constant speed must have force acting on it to make it slow
down. Usually on Earth is friction
2nd Newton’s Law
Newton’s second law tells us the relationship among force, mass and the change in motion.
F= m·a F is the force, m is the mass and a is the rate of change in velocity or acceleration. The
force is directly proportional to its mass. The greater force produces greater acceleration.
Lighter masses accelerate more than heavy masses.
This relationship also provides some units that we can use for forces. Mass is measured in
kilograms, and acceleration is measured in m/s2, the derived unit of force is Newton or N. A
Newton is the force required to accelerate a 1 kilogram mass by 1 meter per second per second.
Force vs. Weight
November 17, 2009
There is a widespread misconception about Force and Weight. Both of them are forced and
Weight is proportional to the mass and gravity. W= m·g. g is the gravitational force which is
There is a difference between unbalanced and balanced forces. Unbalanced forces can produce
motion or changes in motion. Most often there is actually more than one force acting on
objects. These forces are in equilibrium with each other, that is, two equal but opposite forces
produce no motion or change in motion. They cancel each other out. For example, if an object is
sitting on a table, gravity is trying to pull it toward the ground. The table is exerting an upward
force on the object equal to the pull of gravity.
If student teams in a tug of war pull a rope in opposite direction, as long as their pulls
are equal, there is no net movement. Balanced forces produce no net change in motion. If one
team pulls harder than the other, then a net motion occurs along the rope. The forces are
Third Law of Motion
Newton’s third law states that for every action there is an equal and opposite reaction. The air
rushing out of deflating balloon propels the balloon in the opposite direction. This same
principle is used in all rocket motors to propel a spacecraft. The impulse Δp = FΔt, which is a
force applied for a very short period of time, acts on the balloon as it is deflating, and is equal to
and opposite the impulse from the exhaust.
To describe forces we often use scaled arrows called vectors. Vectors have both scale (size in
magnitude) and direction, Forces may act by touching the object, or they may act on an object
over a distance, as gravity does.
November 18, 2009
1. State Newton’s three laws of motion
2. Explain why an object with a larger mass is harder to move than one with smaller mass
3. You throw a ball across a field.
a. Describe its path and direction of movement.
b. Describe the effects of friction and gravity on the ball’s movement.
4. You throw a ball into the air
a. What force is acting on the bass as it moves upward?
b. What happens to the speed of the ball as it is moving upward? Why?
c. What happens to the speed of the ball as it is moving downward? Why?
5. What happens to the motion of an object if no forces are acting on it? Why?
Adding forces as vectors
November 19, 2009
The net force experienced by an object was determined by computing the vector sum of all the
individual forces acting upon that object. That is the net force was the result (or resultant) of
adding up all the force vectors. During that unit, the rules for summing vectors (such as force
vectors) were kept relatively simple. Observe the following summations of two force vectors:
The Pythagorean Theorem
The Pythagorean theorem is a useful method for determining the result of adding two (and only
two) vectors which makes a right angle to each other. The method is not applicable for adding
more than two vectors or for adding vectors which are not at 90-degrees to each other. The
Pythagorean theorem is a mathematical equation which relates the length of the sides of a right
triangle to the length of the hypotenuse of a right triangle.
To see how the method works, consider the following problem:
Eric leaves the base camp and hikes 11 km, north and then hikes 11 km east. Determine Eric's resulting
This problem asks to determine the result of adding two displacement vectors which are at right
angles to each other. The result (or resultant) of walking 11 km north and 11 km east is a vector
directed northeast as shown in the diagram to the right. Since the northward displacement and the
eastward displacement are at right angles to each other, the Pythagorean theorem can be used to
determine the resultant (i.e., the hypotenuse of the right triangle).
The result of adding 11 km, north plus 11 km, east is a vector with a magnitude of 15.6 km.
Lets test your understanding with the following two practice problems. In each case, use the
Pythagorean theorem to determine the magnitude of the vector sum. When finished, click the
button to view the answer.
Vectors and forces
November 20, 2009
1.A book exerts a 1.0 Newton force on a bookshelf. What is the force on the book exerted by the
2. If a moving object is accelerating at 10 m/sec2 due to a force of 10 N applied to it, what is its mass?
3. Add both vectors using the graphic resultant.
November 23, 2009
Friction is the force resisting the relative lateral (tangential) motion of solid surfaces, fluid
layers, or material elements in contact. It is usually subdivided into several varieties.
The frictional force is also presumed to be proportional to the coefficient of friction. However,
the amount of force required to move an object starting from rest is usually greater than the
force required to keep it moving at constant velocity once it is started. Therefore two
coefficients of friction are sometimes quoted for a given pair of surfaces - a coefficient of static
friction and a coefficient of kinetic friction.
Friction shows up in several different forms. The first is static friction. It is the difference in the
force required to start an object moving compared to the force required to keep it moving.
Sliding friction or kinetic friction is the force opposing the motion of sliding surfaces. Rolling
friction is produced when one object rolls over another. Fluid friction is produced when objects
move through the air or other fluids, for example water. It is also called drag.
Rougher surfaces experience more friction sounds safe enough - two pieces of coarse sandpaper
will obviously be harder to move relative to each other than two pieces of fine sandpaper. But if
two pieces of flat metal are made progressively smoother, you will reach a point where the
resistance to relative movement increases. If you make them very flat and smooth, and remove
all surface contaminants in a vacuum, the smooth flat surfaces will actually adhere to each
other, making what is called a "cold weld".
Different materials have different coefficient of frictions, more irregular surfaces have more
November 24, 2009
Many forces act over distances rather than by contact. The most common force is gravity.
Gravity is an attractive force between al objects in the universe. Although gravity is not a very
strong force, it can act over vast distances on all the objects around it. Newton and Kepler
realized that any object that has a mass had a gravitational pull. All the objects in the universe
have a pull for all the others. Newton summarized his Universal Law of Gravitation with the
Which states that the gravitational force between two objects, F, is equal to the universal
gravitational constant, G times the masses of the two objects, divided by the square of the
distance between them r. Larger masses have larger pulls while smaller masses have smaller
pulls. Doubling the amount of the mass of a body will double the attractive force. This inverse
square relationship or inverse square law.
As many other forces that act at a distance do, the gravitational force follows the inverse square
law, that is, if one doubled the distance between tow objects, the gravitational pull between
them would decrease by a fourth; tripling the distance between two objects would cut the
force to one ninth of the original . Gravitation acts only as an attractive force, a pull not a push
Gravitation is the force that causes the acceleration of the orbiting body toward the central
body. Oceanic tides are an observation of the gravitational pull between Earth and moon.
Artificial satellites also depend on the gravitational pull of Earth. Satellites need to reach orbital
velocity to attain Earth orbit. Satellites use several different types of orbit depending upon their
Geosynchronous satellites. - orbit around the Earth at the same speed that Earth rotates. These
satellites are positioned above equator at a distance of 35,850 km, and appear to be in the same
ground location as they orbit. They are also called geostationary satellite. Examples are:
communication and weather satellites.
Polar orbiting satellites pass over most of Earth’s surface during the day. These are Earth
resource satellite, spy satellites and navigation satellites. Low Earth satellites are also used as
spy satellites, taking high resolution pictures.
November 30, 2009
Electrostatic force also follows the inverse square law with respect to distance and, unlike
gravitation, can be attractive or repulsive. Unlike electrical charges attract each other and like
charges repel each other. The force exerted at any point in the field follows Coulombs law that
can be expressed as
F= k (q1q2)/d2
Where the force F is equal to K, the electrostatic constant, the charge q re in coulombs, and is
the distance between the charges. In other words, the larger the charges, the greater the force
and the force decrease rapidly as the charges move apart. Magnetic fields do not follow the
inverse square law. This is because magnetic lines of force do not spread out into a sphere but
instead are controlled by the shape of the magnet and can be concentrated into localized area.
Electrical, magnetic and gravitational fields are vector quantities which mean that they have
direction and strength or magnitude. Depending of the direction and strength, these vector
quantities reinforce or cancel each other.
Electrical force and magnetic force are both aspects of a single force. Electrical currents or
moving electrons, flow through a wire and create a magnetic field. The magnetic field wraps
around the concentric layers.
Magnets also have an effect on electrical currents. A conductor passing through a magnetic field
experiences a force when a current passes through it. Electrical currents also influence other
currents by the magnetic fields they produce. If two conductors have a current moving through
them in the same direction, they tend to attract each other. Conductors with currents moving
through them in opposite direction repel each other. Current in wires produce magnetic fields
evidence those electrical and magnetic phenomena are the result of the same basic principle.
Moving charges create forces that influence other moving charges.
December 1, 2009
State Newton’s gravitational force
How are pairs of charged particles affected by distance and magnitude?
Describe what an electrical current is
How do you predict whether two charges are likely to attract or repel each other?
Electrical forces are vectors. They have both magnitude and direction. If you have 3.0 x10-6
Coulombs of charge on one object and 1.0 x10-6 coulombs of charge on another, at a distance of
0.1 m apart, what is the electrical force between them?
Layering of Earth
December 2, 2009
Earth is made up of four major layers: the crust, the mantle, the core, and the inner core. The
crust is outermost and very thin. The continental crust is thicker and less dense due to its
composition of aluminum and silica, while the oceanic crust is thinner and denser because it is
composed of basalt. The mantle is separated from the crust above it by a boundary called the
Mohorovicic discontinuity. The Mohorovicic discontinuity was discovered by Andrija
Mohorovicic when he observed a change in the speed of earthquake energy waves as they
passed into the mantle.
The mantle’s uppermost parts are solid and its lower parts are liquid. The crust and upper
mantle make up the lithosphere. The lithosphere is the outer solid portion of Earth and is
subdivided into about 20 sections or plates. The lower portion of the mantle is called the
asthenosphere. It is partially molten and very plastic due to high heat and pressure. Its circular
motion moves the less dense lithosphere plates above it. The asthenosphere is also a source of
molten magma during volcanic activity. The core of Earth is subdivided into the outer core and
the inner core and is made of iron and nickel. The outer core is molten and extends from the
bottom of the mantle to the inner core.
Continental Drift and Pangaea
December 3, 2009
Until the twentieth century, scientists assumed that ocean basins and continents of Earth were
fixed in position relative to one another. In 1912, Alfred Wegener questioned all of this
suggesting the idea of continental drift. He used his hypothesis to explain the current positions
of the major continents and how they had moved from past locations to their present one.
Wegener suggested that rock strata, mountain ranges, and fossil evidence found on widely
separated continents indicated that they were at one time next to each other. Wegener
proposed that these major continents once formed a single supercontinent. Pangaea and those
200 million years ago, Pangaea split apart. The parts drifted to the positions we find them in
It was not until 1950’s that new evidence supported Wegenner’s hypothesis. Exploration of the
seafloor showed a banded pattern of magnetic reversals in the seafloor rocks. When molten
lava flows on the surface and cools, the iron crystals it align with the current magnetic field of
Earth. Once, solid, these crystals are locked into position recording magnetic field direction at
the time lava solidified.
Studies of lava on land also showed this phenomenon, what is called paleomagnetism.
Paleomagnetism indicated that the youngest ocean floor occurs along a structure called mid-
ocean ridge. As you move farther from the mid ocean ridge system, the age of the rock
increases. New ocean floor is made at the ridge center, and becomes progressively older moving
away from the ridge.
Evidence supports the Pangaea, as satellites and the contour maps at shorelines.
Explorations have confirmed that a new ocean floor forms as pillow lava squeezes out of the
riffs and fractures of the mid-ocean ridge. Because of these observations, a hypothesis called
seafloor spreading was suggested by Harry Hess in the late 1960’s.
The latest theory is Plate Tectonics that provide explanations for dynamic processes like
mountain building, vulcanism and earthquakes. It holds that the crust of Earth is divided up into
about 20 pieces or plates. These plates move about, sliding, colliding, converging and diverging
with respect to each other.
Lithosphere plate movement is caused by convection cells within the molten rock of the
asthenosphere. Heat convection creates these circular movements of magma and allows the
asthenosphere to move the plates.
December 4, 2009
Name the layers of the Earth and location
How is the last theory about seafloor spreading called?
What is Pangaea? How created this hypothesis? How was this theory corroborated?
Convergent vs. Divergent Plate movement
December 7, 2009
Plates move away from each other and spread apart in divergent movements. This type of
movement forms new seafloor when magma within the asthenosphere wells up to fill the gap
created by the spreading plates. The upwelling magma also forms systems of continuous
underwater mountains called mid ocean ridges. The newly formed crust of the mid ocean ridge
rises higher than the older seafloor because it is hotter and less dense. Heat flow decreases with
increasing distance away from the spreading centers of the plates, and as the new crust moves
away from the ridge, it cools, contracts and sinks.
Slower seafloor spreading produces rift valleys. Rift valley is a central valley or gap between the
crustal plates of a mid ocean ridge. The Atlantic mid ocean ridge has a distinct rift valley with
steep sides. Faster spreading seafloor produces a broad, domelike ridge without a rift valley. The
Pacific Ocean has a broad, domelike rise without distinct rift valley.
Divergent Plates have formed the Atlantic mid-ocean ridge and the Atlantic Ocean seafloor
during the past 165 million years. The Atlantic mid ocean ridge is the longest and largest ridge. It
extends down the Atlantic Ocean from the Arctic to the tip of Africa. It has a distinct rift valley,
active volcanoes, and earthquakes at the spreading centers.
Transform faults cut across its ridges and are sources of earthquakes. Varying rates of plate
spreading from fracture zones are transform faults and their adjacent areas of seafloor are
offset with each other. Research shows that the Atlantic Ocean is widening due to the seafloor
spreading at the mid-ocean ridge. The Pacific Ocean is getting smaller with its outer edges
disappearing at subduction zones.
In covergent plate movement, plates move towards each other. Collision boundaries, plates of
continental crust push upward into a mountain range. Intense faulting, folding and uplifting of
crustal sediments and rocks have formed the Himalayas in Asia this way, the Urals in Russia and
Appalachian Mountains in the United States.
In the process of subduction, a heavier seafloor plate plunges downward under a lighter
continental plate and melts in the asthenosphere. The downward moving plate forms a
subduction zone, a deep sea trench, which is a deep sea trench. The Mariana trench is the
deepest trench in the Pacific Ocean. It was formed by subduction of the Pacific Plate under the
Philippine plate. In addition, when oceanic plates plunge under continental plates, volcanic
mountains are formed on the land above the subduction zone. The Andes Mountains in South
America are an example.
As two seafloor plates collide, one plate bends and descends under the other. New magma rises
and volcanic island arcs such as Japan can form.
The island arch is a chain of volcanoes on the landward side of the subduction zone. Island arcs
occur in the Atlantic and Indian oceans, but are more numerous in the Pacific Ocean where they
help form the Ring of Fire, a chain of active volcanoes along the edge of the Pacific Plate. The
Marianas Islands are a chain of volcanic islands and they form the leading edge of the Philippine
Plate. Other island arcs are Aleutian Islands, the Philippines, the East Indies and the Antilles.
December 8, 2009
Earth’s crust shakes as energy is released during an earthquake. Earthquakes are associated
with certain plate boundaries, such as the San Andrea fault system and mid-ocean ridges. They
have occurred in many different places and have produced perhaps the most notable
consequences in Japan, Alaska, and California.
Earthquakes create devastating damage in Japan, Alaska and California. Earthquakes create
devastating damage because they cause buildings to collapse, start explosions and fires, and
break sewage and power lines. Earthquakes may cause tsunamis (giant tidal waves), food
shortages, disease and personal tragedy.
Earthquakes are generated by forces inside the Earth. The elastic rebound theory says that
friction and plate distortion prevent rock on both sides of the fault from slipping. The resulting
stress causes the plates to snap and move once the frictional resistance is exceeded. This
sudden movement is an earthquake. Volcanic eruptions, meteors impacts, and landslides can
also cause earthquakes.
The focus of an earthquake is the point at which the first movement of the Earth begins. How
deep inside Earth the earthquake occurs depends on where the earthquake occurs, that is, the
Earthquake’s location. For example, spreading center and sliding boundaries produce
earthquakes less than 70 km deep, while at subduction boundaries deep focus earthquakes will
be 700 kilometers. The focus is also the source of energy released by an earthquake. It releases
energy that travels to the epicenter, the area of Earth directly above the focus. This energy then,
travels outwards from the epicenter as surface waves.
Earthquakes produce three types of waves:
P waves or primary waves. Created when rock material is alternating compressed and stretched
by back and forth motion on Earth’s crust. P waves cause particles to move in the same
direction than the wave. P waves can travel through anything, solid, liquid or air.
S waves or Secondary waves. Are produced with side to side movement on Earth’s crust
causing the particles to move in right angles to the direction of the travelling wave. S waves
travel through solids but not through liquids or air. S waves are slower than P waves. Both of
them are called body waves because they can through Earth’s body.
Surface or L waves. They travel on Earth’s surface and they are slower than P or S waves.
Seismographs are used to detect earth waves. They can determine how far away is the
epicenter of the earthquake is from the seismograph.
Seismograms record P, S and L waves as they arrive to the seismograph. Some seismographs do
not receive all of the three waves, those which do not receive P or S waves are said to be in the
shallow zone. Shadow zones are caused by Earth’s outer core, which causes P waves to bend
and avoid the broad belt around Earth. S waves do not pass through shadow zones because
they cannot penetrate outer core.
The magnitude or strength of an earthquake is measured in the Richter scale. It measures the
energy released by an earthquake. The scale ranges from 1 to 10, with each unit being 32 times
more than the magnitude of the number before.
December 9, 2009
Volcanoes allow molten rock or magma to travel to the surface of the crust. There, the magma
becomes lava, and when layers of lava and volcanic ash accumulate, a volcanic mountain is
Magma is extremely hot and under great pressure, is part of asthenosphere. Magma contains
dissolved gases. The bubbles of gas contribute to its explosive nature.
Volcanic gases are: water vapor, carbon dioxide and sulfur dioxide mostly.
The rate of the magma flow is determined by its mineral content. In all magma, silica is the
major component. Slower moving magma has more silica. Mafic magma flows easily than Fesic
Lava is either mafic or fesic. Mafic lava is more explosive because loss of fluidity.
Tephra are solid fragments of lava that have been produced by explosive volcanic eruptions.
They are classified according to type and size. The larger types are blocks and bombs, they are
determined by consistency at the time of ejection; blocks are solid at the time of eruption, and
bombs are ejected liquid. Tephra may combine with gases to form moving lethal clouds of
pyroclastic flow that moves at 100 km/h.
Massive volcanic explosions occur when the magma solidifies and blocks the surface opening of
volcano. The water inside the magma chamber may build pressure and produces steam. This
pressure can create a violent release.
A sudden escape of gas can also cause an explosion. One example is the explosion at Mount St.
Helen. After eruption, the top of volcano may collapse to form a depression called caldera. The
caldera may form a lake if filled with water, like Crater Lake Oregon.
Cooling of the magma while it is still underground may produce large masses of rock called
batholiths. Batholiths are usually made of granite. These rock masses form igneous intrusions
and form the bases of mountain ranges.
Igneous intrusions and batholiths may also be called plutons.
Laccoliths are igneous intrusions formed by the movement of slow magma in areas beneath
rock layers. Volcanic necks form when extinct volcanoes are eroded away to expose plugs of
magma hardened within vents.
Types of Volcanoes
December 10, 2009
Volcanoes occur at divergent, convergent plate boundaries and hot spots. At divergent plate
boundaries, they form mid ocean ridges. The occur along the mid Atlantic Ridge all the way from
Iceland, which sits on top of the mid Atlantic Ridge, to the Antarctic Plate. They also occur at the
east pacific rise.
Themid Atlantic Ridge and East Pacific have rift eruptions, which are long narrow crustal
fractures that oozone lava. Rift eruptions release slowly, and when underwater, the form large,
rounded masses of pillow lava. Rift eruptions can also occur in land.
Vents are the opening of volcanoes throughout magma flows out. When magma comes out of
vent is called lava.
Types of volcanoes
Have mild eruptions
Magma rich in iron and magnesium
Very fluid magma, flows great distances.
They have gentle sloping mountain.
Example: Hawaii volcanoes like Mauna Loa
Made of alternating layers of ash, cinder and lava.
Lava rich in silica
Very viscous magma, gases are trapped in magma, causing large eruptions.
Very high volcanoes
Very steep slope
Example; Japan, Mount Fuji
Smallest and more abundant
Large amounts of gas trapped in the magma, violent eruptions.
They are active only for short period of times.
Great quantities of ash and hot lava are thrown out throughout the vent, forming a cone.
When volcanoes form in water are called seamount.
Example: Paricutin in Mexico
December 11, 2009
Match the descriptions below with the appropriate term
________ Plate boundary found at mid ocean ridge a. convergent
________plate boundary forming a trench b. lateral
________island arcs form at this type of boundary c. divergent
________ Plate boundary formed by plates sliding d. transform fault
________feature running along the west coast of North America e. craton
________oldest continental rock
Identify the differences between seismic waves.
Which wave is more destructive? Explain why
State the different types of volcanoes and their characteristics.
What is lava? What is magma?
December 14, 2009
A continental margin is the outside edge of a continent. Continental margins can be active or
passive. Active continental margins occur along convergent plate boundaries. They have active
volcanoes, faults and frequent earthquakes. The west coast of South America is an active
continental margin due to the subduction of the Nazca Plate under South America Plate.
Passive continental margins occur away from plate boundaries. They have fewer earthquakes,
fewer volcanoes and faults. They are wide and contain coral reefs.
Continental margins are composed of a continental shelf, continental slope and continental rise.
The continental shelf is flat land that extends outward, underwater, to a depth of 200 meter.
Continental shelves are very valuable because they are sites of oil, natural gas and mineral
deposits. They have the greatest number of marine organisms. This productivity is due to a
stable environmental condition of salinity, light, temperature and pressure.
The continental slope is the wall of the ocean basin. It begins at shelf break, where the shelf
becomes the slope. The steepness of the slope varies from place to place. On active continental
margins, the slope ends in a trench; on passive and active coasts, the slope ends in continental
rise; and in some places is eroded by sediment, producing currents called turbidity currents that
form submarine canyons. Submarine canyons are V shaped cuts in continental shelves and
The continental rise forms at the base of the continental slope. It is formed from the
accumulation of a wide band of loose sediments of mud, silt and sand. The accumulation of
sediments may be due to subduction or the outward flow of sediments from passive continental
Abyssal Plains are flat, open areas of seafloor that extend beyond continental margins. The
abyssal plains are 4000-6000 meters in depth and may be covered with loose unconsolidated
sediments or oozes.
There are 4 classes of sediments:
Biogeneous- remains of plants
Lithogenous- continental crust
authigenic, - water
cosmogenic (derived from meteorites)
Other features of the seafloor are Abyssal hills. Only a few hundred meters high, and often
covered with sediments. They are about 1- 10 km wide.
Seamounts are found in the seafloor and they are inactive, isolated volcanoes that have a height
of 1,000 m or more. When their tops become eroded, they become guyots.
Atolls are circular or horse-shoed coral reefs that may grow in volcanic islands. AS the islands
sink, atolls continue to grow upward, creating a lagoon in their center.
December 15, 2009
There are four kinds of mountains: folded, upwarped, fault-block and volcanic.
Folded Mountains- They are formed during plate collisions, layers of Earth are pushed together.
The oldest mountains are the Appalachian Mountains and are about 300million years ago. They
are about 2000 m over the sea level. Valleys between folded mountains are created by the
weathering of rock in different areas at different rates.
Upwarped mountains (uplifted mountains) are created by upward movements of the rock
layers within the Earth. Peaks and ridges of these mountains are formed by the erosion of
sedimentary rock on the tops of the mountains. The Black Hills in South Dakota.
Fault-block mountains- form when entire blocks of crust fault and uplift at the same time. Fault
Block Mountains have sharp jagged peaks and their slopes vary in steepness on each side.
Example: Sierra Nevada in California
Volcanic Mountains- formed by upward surges of molten rock. Mount St. Helen in Washington.
Plains are large, flat areas of land at low elevations. These lowlands can be coastal or interior
Coastal plains occur near oceans and may flood with water to form grassy wetlands such
Interior plains occur farther away from coastal areas. They occupy a large part of the United
States. Interior plains, called prairies, are often farmlands.
Plateaus are flat areas of land at elevation higher than those of plains. Example: The Colorado
Minerals and Rocks
December 16, 2009
The lithosphere or crust is made of elements and compounds that interact and are organized in
different ways. The crust is made of eight elements: oxygen, silicon, aluminum, iron, calcium,
sodium, potassium, and magnesium.
The major group of minerals include: silicates, carbonates, oxides, sulfides, halides, hydroxides,
phosphates, and native elements like gold, silver, copper, sulfur and diamond.
Crustal elements form rocks and minerals.
Minerals are inorganic, and are not formed by processes involving organisms. Most minerals
are compounds. For example quartz is made of silicon and oxygen. Minerals have a crystalline
structure, that is, atoms have a repetitive pattern and their internal structures are distinct.
Minerals are geometric solids and may have smooth surfaces called crystal faces. There are
more than 2,000 known minerals. Most are silicates. Some are also gems. Diamonds are gems.
Characteristics of Minerals
Hardness; Minerals have their atoms or ions very close together. The strength of these forces
determines the hardness of mineral. The hardness of the material is determined how easily the
material can be scratched. The scale used to measure the hardness of a mineral is the Mohs
scale. The scale range from 1- 10, 10 being the hardest.
Luster: It is the property that indicates the way light is reflected by a mineral’s surface. Both
metallic and nonmetallic minerals have luster.
Non metallic minerals may be described as dull, pearly, silky or vitreous (dull).
3. Color: Color by itself is insufficient for mineral identification. For example, sulfur is
4. Streak: refers to the color of a mineral as it is broken up and powdered while being
moved across a streak plate, leaving a line. To leave a mark on the streak plate, the mineral
must be softer than the streak plate.
5. Cleavage. It is the way a mineral splits apart along flat surfaces. Cleavage is determined
by the arrangement of the atoms.
6. Density. Is the ration of mass to volume?
Some minerals, such as limestone, contain compounds that can be dissolved by acid. The
acid test uses hydrochloric acid.
Another way to identify minerals includes fluorescence and phosphorescence. Radioactivity
which is the emission of subatomic particles from atomic nuclei, light refraction (bending of
the light) and the shape may also be used to identify minerals.
Ores: are minerals from which a specific substance can processed and refined for
Types of Rocks
December 17, 2009
There are three categories of rocks: igneous, metamorphic, and sedimentary.
Igneous rocks are the most abundant type of rock on this planet. Hot magma cools and hardens
to form igneous rock. Igneous rocks formed below the surface of the Earth are intrusive or
plutonic. Intrusive rocks must be exposed at the surface in order to be visible and is
characterized by large mineral grains. Lava-formed rock is called volcanic or extrusive, its
texture consists in finer mineral grains, and its internal structure is less organized than intrusive
rocks. Examples of extrusive igneous rocks are: pumice, obsidian and scoria.
Rocks may also be classified by their magma composition and type:
Basaltic rocks: rich in iron and magnesium, dense and dark in color. Examples are: gabbro,
basalt, and scoria.
Andesitic rocks: are intermediate to granite and basal in chemical composition and density.
Examples: diorite and Andesite.
Granite: forms from felsic lava; it has a lower density than the other rock types. Granite rocks
such as pumice may be porous and spongy because they hardened while gases were still
bubbling within them. Granite rocks are lighter in color than basaltic rocks. They are rich in silica
and oxygen and released during violent volcanic eruptions. Examples are: granite, pumice, and
They are formed from igneous, sedimentary or other metamorphic rocks due to intense
temperature, pressure and changes in composition. (This process is called regional
metamorphism and occurs during the formation of mountains). Metamorphic rocks are
classified according to their texture; they may be foliated or nonfoliated.
Foliated rocks have parallel layers. They include slate, and gneiss.
Nonfoliated rocks do not have parallel layers or bands. They are produced by contact
metamorphism when rocks near hot magma are cooked by its intense heat and absorb its hot
liquids and gases. Examples are: quartzite and marble.
Although most rocks below the surface of Earth are igneous rocks, 75% of the rocks on Earth
surface are sedimentary rocks. Sedimentary rocks form when loose, unconsolidated sediments
precipitate our of a solution or are compacted together in layers. Sedimentary rocks originate
from preexisting rocks that have become weathered, eroded and stratified; they may also
contain remains of fossils.
There are three types of sedimentary rocks. Their classification depends on their composition
and the way they were formed.
Clastic sedimentary rocks form from rock fragments produced by weathering of preexisting
rocks. These fragments are cemented together by dissolved materials as silica, calcite and iron
oxide. Examples: shale, sandstone, and conglomerate. Clastic sedimentary rocks may also be
called detrital sedimentary rocks.
Chemical: sedimentary rocks form by precipitation or when minerals are left behind by
evaporation. Examples: limestone, gypsum and halite.
Organic sedimentary rocks form from remains of once-living things. Example: coquina, coal,
limestone and chalks.
The different rock processes are summarizing in a rock cycle graph:
Rocks leave a record. Earth has been around for a long time (4.6 billion years), and it is possible
to document the ages of Earth’s past events. There are two methods for doing this: relative
dating and absolute dating.
Relative dating. The ages of the rock can be determined by the location of those rocks within
Earth’s stratified layers. It is based on the premise that oldest rocks will lie on the bottom and
youngest rocks at the top. It does not give an exact date of when rocks are formed. This is called
the Principle of Superposition.
Absolute dating. It does provide a specific date for an event. It is used half life or radioactive
isotopes. The length of the half life determines where and how it is used in dating studies.
Both relative time and absolute time are used to describe geologic time.
December 18, 2009
1. Explain why populations of plankton are greater in waters over the continental shelf.
2. Explain why seashells can be found in top of mountains.
3. Why do scientists use different radioactive elements and their half lives to determine the ages
4. What is the principle of superposition?
5. How are igneous rocks formed? How many types of igneous rocks can be found?
Composition of atmosphere
January 5, 2010
Earth is a multilayered sphere. Its outermost layer is the atmosphere. The atmosphere is
divided into four layers: the troposphere, the stratosphere, the mesosphere, and the
1. The troposphere is the lowest and most dense layer of the atmosphere. It is where
weather occurs, and most dense layer of the atmosphere, and where we live in. It is where
weather occurs, and it is the atmospheric layer we live in. The troposphere and its mixture of
gases are important to life on Earth. It contains about 75 % of mass of Earth’s air. 95% of this air
consists of nitrogen, oxygen, argon, carbon dioxide and trace gases. In the troposphere system
of air currents and winds in the lower levels help create weather. Temperature decreases as the
altitude increases. This decrease of temperature ends at the top of the troposphere, which is
the tropopause. This temperature difference prevents the mixing of the troposphere with the
atmosphere layers above due to their differences in densities.
2. The stratosphere. The second layer of the stratosphere lies above the troposphere. It is
clear, dry and calm. Its temperature increases with altitude. The air of the stratosphere is thin
and the weather is constant. It has a high ozone content that forms the ozone layer. The ozone
layer filters about 99% of ultraviolet rays. The ozone layer protects the Earth from harmful U.V
light rays. The ozone layer is thinning due to the release of pollutants. Chlorofluorocarbons
(CFC’s) are an example of pollutants that destroy ozone. The CFCs are used in aerosol bottles
and refrigeration systems. They are now banned because they destroy the ozone molecules.
3. The mesosphere lies above the stratosphere. Temperatures decrease rapidly as the altitude
in the mesosphere increases. The uppermost boundary, which is called the mesopause,
atmospheric temperatures are at the lowest.
4. Thermosphere. It is the layer above the mesosphere. Temperatures in the thermosphere
increase because nitrogen and oxygen in this layer absorb solar energy. The mesosphere and
the thermosphere also contain the ionosphere.
The ionosphere is named for its large concentration of ions. Ion concentrations vary and may
affect the transmission of radio waves and satellite communications. Solar flares or charged
portions of the solar atmosphere blown to Earth, contribute ions to the ionosphere. Earth’s
magnetic fields deflect these ions to its polar regions to create auroras (such as the Northern
lights), which are energized air molecules that gives off light.
January 6, 2010
Atmosphere/ Heat Energy
It is the energy of the sun that drives many of the phenomena called weather.
Weather is the state of condition of the atmosphere at any given place or time. The amount of
energy supplied by the sun varies over the surface of the planet according to the latitude. At the
equator, more solar energy is absorbed by Earth, and it is reduced as one move away from the
equator and toward the poles. The incoming solar radiation striking Earth is called insolation.
Sunlight is more readily absorbed at the equator because the light rays are passing directly
down into the atmosphere. As you move toward the poles, light strikes the atmosphere at an
angle, and is reflected, that is, bounces off the atmosphere and clouds, so it is less absorbed.
Thermal energy can move in three major ways:
Radiation is the flow of electromagnetic energy or waves. This is the way that visible sunlight
enters our atmosphere after travelling throughout space from the sun. Some light does not
penetrate our atmosphere. For example, clouds reflect light back into space or it is absorbed.
Some light that reaches the Earth can come back to atmosphere too.
Earth’s heat budget is a temperature balance of the heat gained by absorption and the heat lost
by reflection and radiation. A phenomenon that influences the amount of radiation lost into
space is the greenhouse effect. Gases like carbon dioxide, water vapor and CFCs block the
radiation of heat energy, causing the atmosphere to heat up. Over time, this will cause the
planet to come warmer and warmer if more greenhouse gases are added.
When sunlight is absorbed, its energy can be moved by conduction, or molecular collision.
Conduction always moves energy from hot to cold. Heat is also moved in liquids and gases by
convection. When heated, these liquids and gases change density with respect to their
surroundings. Hot air rises, and cold water sinks, Convection is the most important of these
processes in the hydrosphere and atmosphere.
Heated air rises in convection currents, moving heat from the bottom of the atmosphere to the
top. It is convection currents, moving heat from the bottom of the atmosphere to the top. It is
this convection glow of the atmosphere along with the rotation of the Earth that creates the
major wind belts over the surface of the Earth. By moving ocean water from the equator toward
The atmospheric temperature varies according to differences in insolation, altitude and location.
Seasonal variation in atmospheric temperatures occurs because of the different angles that the
sun’s rays penetrate Earth’s atmosphere. Rays penetrating at 90 degrees are more effective
than those penetrating at a lesser angle, where sunlight has to pass through more atmospheres
and is spread out over a wider surface of insolation over the period of a year. In the northern
atmosphere, there is more insolation over the summer, while in the southern atmosphere;
there is more insolation in the winter.
The maximum and minimum temperature changes occurring over a year are the seasonal
temperature range. Daily or diurnal temperature variations also occur due to differences in
insolation from early morning to noon. The daily temperature difference between the
maximum and minimum temperatures is the daily temperature range.
The temperature on Earth cools down according to the altitude, the highest over the sea level,
the colder that it is. This cooling is about 1 C for every 160 m of altitude and it is called the
normal lapse rate.
Water is the only substance that heats and cools more slowly than land. This is because water
has a high specific heat.
Specific heat is amount of heat required to raise the temperature of 1 gram of a substance 1 C
degree. Because of the high specific heat of water is really high, water holds heat very well in
oceans and rivers. Water also reflects low angle insolation than land. Light penetrates only a
January 7, 2010
Pressure is defined as the force per unit of area. The weight of the atmosphere causes air
pressure. In every square inch, the air exerts 14.7 pounds of pressure. We measure pressure
using a barometer, which is a sealed glass tube with one end open placed below a bowl of
mercury. 1 atmosphere of pressure is equal to 760 mm of mercury (Hg), about 30 inches. As
pressure rises or fall, the mercury rises or falls too.
Another type of barometer is the aneroid barometer that measures pressure changes with an
expanding or contracting metal container. A barograph is an aneroid barometer with a chart
recorder. It is used for measuring pressure in planes. Air pressure can be expressed in millibars,
or inches of mercury.
The number of inches of mercury can be converted to millibars by multiplying each inch of
mercury by 34.0 millibars. Air pressure is shown in a weather map with lines called isobars.
Isobars join map points that have same air pressure at a given time. They are about 5 to 10
Daily weather maps show that air pressure is always changing. The changes are usually due to
variations in atmospheric pressure. Warmer air, lower pressure. Isobars enclose areas of higher
air pressure called h high pressure centers. High pressure areas occur in the center of air
masses and forms hills of airs. These hills or air have higher pressure than low pressure centers.
The air pressure flows from the high to the lowest pressure area. On the weather map, the
closer isobars are to each other, the greater of the pressure gradient. The farther apart the
isobars are, the weaker of the air flow due to the lower pressure gradient.
They are formed by the uneven heating of the Earth’s atmosphere. They are driven by solar
heating next to the equator. Air is heated at the equator and travels toward the poles. This
produces an isolating pattern called a convection cell. Earth rotates and makes wind patterns
more complicated. Because of Earth’s rotation, major winds are deflected to the sphere. This
deflection is called Coriolis effect. No Coriolis effect is produced at the equator, and hot air
moves straight up, forming pressure belt called the doldrums. The Coriolis Effect is affected by
wind speed. The faster of the wind, the greater effect. Slower winds less Coriolis Effect.
The deflections by the Coriolis Effect above and below the equator produce three global wind
belts, or circulation cells, in each hemisphere. The circulation cells are called Hadley cells.
The first Haley cell occurs between 0 and 30 degrees of latitude. Above the cell are two
additional circulation cells, one between 30 and 60 latitude. The third cell is driving by cold air
falling at the pole and occurs between 60 degrees and the poles.
Air in high pressure systems also moves in circular patterns. In the northern hemisphere, air in a
high pressure system flows downward and away from the center in a clockwise direction. Air
moving into a low pressure system rises and spirals in a counterclockwise direction.
Winds are named according to the direction from which they blow. Prevailing winds blow more
from one direction than any other. The wind belts occur within specific latitudes, and the wind
belts in the northern hemisphere are a mirror image than those in the southern hemispheres.
The wind belts also represent areas of low and high pressure. Polar Regions are high pressure
Wind speed and direction are important in the study of the weather called meteorology. Wind
direction is determined by using a wind vane.
An anemometer measures wind speed, which are related to their observed effects on land and
sea and listed in a special scale called the Beaufort scale.
Atmosphere and weather
January 8, 2010
Create a pie chart showing the concentration of gases in the air of the troposphere.
How do the layers of the Earth’s atmosphere differ from each other?
Contrast how radiation, conduction and convection differ from one another
Describe how greenhouse gases such as carbon dioxide influence atmospheric pressure
What is air pressure? Compare isobars and millibars.
January 18, 2010
Ocean currents and water cycle
Weather is defined earlier, is the state or condition of the atmosphere at any given place or
time. Precipitation, temperature, wind speed and direction, atmospheric pressure and humidity
are all parts of the description of weather.
Air masses are large bodies of air that have the same weather throughout. They occur in lower
atmosphere and have uniform temperature and humidity. Air masses form in parts of the world
where winds are light as, for example, in polar and subtropical high pressure belts. Because air
masses acquire the moisture and temperature of the area over which they lay, their
characteristics depend on where they form and how long remain there. Air masses are named
for their place of origin and are given two letter codes to specify their temperature and
Air masses bring weather changes and create weather conditions in air mass boundaries. The
changes air masses create can be minor or major, depending upon the kind of air mass. The
weather under an air mass depends upon the temperature of the surface- the air mass lies over.
For example, if the ground surface is cooler than the air mass, the bottom layer will be stable
with temperature inversions trapping smoke and pollution and causing poor visibility and smog.
If the ground is warmer, the bottom layer of air will be unstable with convection forming
cumulus clouds and air layers mixing. Condensation of water vapor may cause precipitation,
dew or fog.
Front-is the leading edge of an air mass and forms at the boundary of an air mass. Weather
fronts may be classified in four types:
Warm Front- Warm air pushing into and displacing cold air
Cold Front- Cold air pushing and displacing warmer air
Stationary- Neither air mass moves nor is displaced
Occluded- Cold front overtakes a warm front
A mid-latitude low is an area of low pressure formed by a cold front and warm front coming
together. This forms a frontal wave. A three way frontal boundary is then formed and includes
the cold, warm and occluded fronts. This begins a counterclockwise air circulation that is also an
area of low pressure. This counterclockwise air movement is also called a mid latitude cyclone.
These can become very destructive storms.
The Water Cycle
January 19, 2010
Water moves throughout the hydrosphere of Earth. The hydrosphere is the liquid part of the
Earth. It includes all of Earth’s lakes, streams, rivers, oceans, ice and water vapor in the
atmosphere. This water circulates among oceans, atmosphere, and land in a continuous
movement called the water cycle (hydrologic cycle). The water cycle allows Earth to recycle and
redistribute its limited supplied of water.
The water cycle is powered by sun and gravity. Water evaporates from oceans, lakes and
streams into the atmosphere. When water or other liquids evaporate, energy is required to
change the liquid to a gas or vapor. This process is called evaporation. Evaporation’s energy
comes from the sun and is absorbed from the surrounding environment. Because of this energy
loss evaporation is a cooling process, and the surrounding environment become cooler.
Transpiration is the release of water vapor from the leaves of a plant, it also a cooling process
and adds water vapor to the atmosphere.
Water vapor returns to Earth’s surface by condensation and precipitation.
Condensation- occurs when water vapor changes to liquid water. This process heats the
surrounding environment by releasing heat energy absorbed from evaporation.
The amount of water the air holds (specific humidity) depends on air temperature. Warm air
can hold more water vapor than cold air. The air is saturated when cannot hold more or absorb
more water vapor.
Relative Humidity also indicates how much water vapor is in the atmosphere. Expresses how
close the air is to its capacity. Capacity is the maximum amount of water vapor the air can hold.
Humidity is measured with a hygrometer. Relative humidity is measured with a type of
hygrometer called sling psychometer. A sling psycho meter has two thermometers, by
comparing the readings in both of them, the relative humidity is determined.
When air cools, it may have to get rid of some of the water it is carrying as vapor. If the amount
of vapor exceeds the carrying capacity of the air, then the vapor will condense or change into a
liquid and form liquid droplets. Larger droplets form clouds or fog.
Condensation releases heat energy into the air. It slows the condensing process and the rate at
which the air cools after it reaches the dew point. The dew point is the temperature at which
condensation occurs. Continued cooling results in larger and larger droplets of water will form
As air cools, it radiates heat into the upper atmosphere. This also allows its water vapor to
condense. When most air mixes with colder air or expands as it rises, it will also cool and its
water vapor will condense to produce rain, clouds or snow.
Air may be cooled below its dew point without producing condensation. This is called
supersaturated air. Water also requires a surface on which to condense, a condensation
nucleus. Tiny particles of dust, salt, sulfates, nitrates, smoke and ice crystals are all good
The remainder of the water cycle includes precipitation and run off. Water condenses from
clouds and returns to Earth as rain, sleet or snow. This is precipitation. Some of this water
moves into the soil by infiltration and eventually percolates down through soil and porous rocks
and become groundwater. Ground water can move through the porous rock in aquifers. The
porous rock of an aquifer filters the water and improves its quality. This allows us to use
groundwater as drinking water. Water can also move over and below Earth’s surface as a
runoff. Surface and groundwater runoff return water to oceans, rivers and lakes, the cycle
Clouds and Precipitation
January 20, 2010
Clouds are condensed water vapor, a high fog, mist or haze. Clouds form when the air cools
below its dew point. These clouds are suspensions of water droplets as long as the air
temperature is above freezing. If the air temperature goes below freezing, the clouds exist as
ice crystals or supercooled water. If this super cooled water condenses on a solid surface, it will
form rain or snow. Many clouds occur as ice crystals due to the cold temperature of the
atmosphere. In the lower atmosphere, where temperatures are warmer, the clouds are masses
of water droplets.
Clouds types and shapes are determined by air temperature, altitude, relative humidity and air
movement. There are three basic cloud types: cirrus, stratus, and cumulus. Others are
combination of these three basic types.
Cumulus- is thick, piled, puffy clouds. They are formed by air moving vertically over a heated
surface. They may have flat bases and extend upward to very high altitudes. They form at the
bottom of the cloud base, which is where the water begins to condense. The altitude at which
this occurs is called the condensation level, and at that level, the temperature is the same as
that of the dew point.
Cirrus- is high, feathery, thin clouds. Because they occur at high altitudes, above 20,000 feet,
they re made of ice crystals.
Stratus- They are low sheets or layered clouds. They are associated with horizontal air
The prefix alto and the word nimbus are used in modifications of the three basic cloud names.
For example altostratus clouds are sheets or layers of clouds happening at higher levels, while
nimbostratus clouds are dark and gray layers of clouds at lower altitudes.
Cloud formation is affected by vertical movements of air currents, their rate of temperature
change (also called lapse rate), the altitude where water vapor condenses (condensation level)
and the release of heat that stimulates vertical air movement.
Precipitation is the downward movement of water to Earth’s surfaces. It may be rain, snow,
sleet or hail. Raindrops or water droplets form when smaller water droplets in a cloud collide
with each other and coalesce. As more collisions occur, the droplets get bigger and bigger until
upward currents cannot longer support them. For precipitation to occur, the water droplets
must be big or heavy enough to fall through the air. Water droplets can also form ice crystals.
As the ice crystals fall to lower altitudes and warmer air, they melt into water droplets. Rainfall
is measured using a gauge that indicates the amount of rain by the depth of water collected.
Types of precipitation.
Precipitation can take many forms. Small, slow falling raindrops are drizzle.
Clumps of six sided crystals form snow.
Sleet forms when partially frozen mixtures of rain and snow form ice pellets at temperatures
just above freezing.
Ice storms occur when super cooled rain instantly freezes on contact.
Hail is formed when ice is added layer by layer as it moves up and down within cumulonimbus
Hailstones are frozen raindrops.
Hurricanes are large, whirling or cyclonic windstorms. They form in low pressure areas over
warm tropical waters. In the northern hemisphere, they form during the months of June to
December, this is called hurricane season.
The warmth of the ocean water, which must be above 81 F, provides energy to strengthen the
hurricane. This energy is derived from the latent heat of evaporation and is released into the
atmosphere as the water condenses to form rain. As more and more energy is released, the air
expands and rises and hurricane gets stronger and stronger, with wind speeds sometimes
exceeding 250 km/h. Meteorologists rate hurricane intensity by the Saffir- Simpson scale.
Hurricanes rotate in a counterclockwise direction in the northern hemisphere. Most of them
form in the atmosphere of the intertropical convergence zone. The ITCZ is a pressure boundary
layer in the atmosphere between the doldrums and the tradewinds. A hurricane watch is issued
36 hours before land fall. A hurricane warning is issued 24 hours or less.
Acid Rain forms when particles of dry sulfur or nitrogen oxides serve as nuclei for raindrops.
Nitrogen oxides react with water to form nitric acid and nitrogen oxide. Then a succession of
reactions occurs until the last product sulfuric acid is formed. This produces acidic droplets of
rain that can cause acidic damage when they come in contact with surfaces of leaves, metals,
building materials and soil. Also acid rain damage is small bodies of water.
January 21, 2010
Climate is the annual average of weather conditions at a given place over a long period of time.
Factors that affect climate
Climate is affected by environmental conditions at a locality or region. These conditions or
factors include: latitude, mountains, and large bodies of water, wind belts and urbanization.
Latitude is the angular distance away from the equator. It is measured in degrees. How close a
place is to the equator or the poles affects its climate. This is because insolation is more direct
in the equator.
Mountains affect climate because their elevated tops acts as barrier to wind. As air rises, it
cools. This is called adiabiatic cooling, which is the compression or expansion of air due to
temperature change. Mountains also affect precipitation. How near a land area is to water also
affects climate. Land close to the ocean has slow changes of temperature because of water high
specific heat and large heat capacity. This means that temperature changes on land will be low.
Wind belts affect climate because they determine the direction of surface ocean currents.
These, in turn, influence the temperature and climate of nearby coastal areas. Cold winds
arriving from inland areas can cause cool weather. Regions affected by sinking moist air
currents have cloudiness and precipitation, while regions located along the equator and
midlatitudes have rising air currents with less precipitation.
Urbanization affects climate because it replaces vegetation by concrete and asphalt, which
affects the absorption of heat energy. Buildings, asphalt, automobiles and industry release heat
energy. This alters rainfall patterns and increases temperatures in the city.
Seasonal, climatic changes occur in temperature zones. Recent, recurrent climatic changes have
occurred every few years due to the phenomenon of EL Nino.El Niño is a change in wind,
weather and current patterns in the tropical Pacific Ocean. Warm equatorial currents are
diverted into colder waters by atmospheric pressure and wind pattern changes. El Niño affects
weather along the coasts of California and South America by changing precipitation and wind
patterns. It has caused drought and famine in Africa and has been linked to global warming.
Climate, Precipitation and water cycle
January 22, 2010
Describe the process in which a cloud becomes rain
What impact do humans have in the water cycle?
Explain how the presence of warm ocean water on both sides of the Florida peninsula affects its
Compare the climate of a coastal area to an inland climate
Explain why a desert occurs on the leeward side of a mountain.
January 25, 2010
Surface currents are large, horizontal movements of water driven by wind. Surface ocean
currents are important because they transport heat energy from the equator to the poles; they
also carry warm water to colder climates and warm them. Ocean currents also affect the
distribution of marine organisms by transporting them to new habitats. Surface ocean currents
travel in circular patterns called gyres, because they deflect from Coriolis forces when their east
west flow is obstructed by continental land masses.
Water density increases as temperature decreases and salinity increases. The cooling and
freezing of polar waters and evaporation of warmer waters increase water density and form
density currents. These slow movements are not affected by wind and move at deeper depths
independently of surface waters.
Ocean surface waves are produced by wind blowing on the water surface. When a deep water
wave goes by, it is the wave form and energy from the wind that is moving. This is because, as
the wave travels, the water moves in circular pattern, circling downward and then upward to
return to its original position. The diameter of these circles decrease with increasing depth until
at a depth equal to one-half the wavelength, there is not movement. When this part of the
wave comes into contact with the beach bottom, the wave becomes a shallow water wave.
The height of a wave is determined by the speed of the wind, how long it blows, and the size of
the area over which it is blowing (also called fetch). The time it takes a wave to pass a specific
point is called wave period. The speed of the wave is determined by dividing the wavelength by
the wave period.
Surface ocean waves are named according to the relation to where they are generated or
formed. Waves with sharp crests in the area of fetch travel in all directions and are called seas.
Swells are waves that have rounded crest and travel in sets. They have left the area of fetch.
When waves come on shore they are called surf or breakers.
Tsunamis-are often called seismic sea waves because they are usually caused by earthquakes.
These long period waves have huge wave heights when they enter the continental shelf and
cause great damage. Tsunamis are actually caused by vertical displacement of seawater, which
can be generated by movements of the seafloor.
January 26, 2010
Tides- they are the daily rhythmic rise and fall of the ocean. They occur along coastlines and are
caused primarily by the gravitational pull of the moon, and, to a lesser extent, the gravitational
pull of the sun. Both moon and sun cause a tidal bulge of water to form on the side of Earth
facing the moon. On the other side of the Earth, a second tidal bulge forms due to centrifugal
forces. The bulges represent high tides.
Tides are actually long period waves. A high tide is the crest of the wave, while low tide is the
trough. The vertical difference between high and low tide heights is called tidal range. Tidal
ranges vary throughout world’s coastlines, with the greatest tidal ranges occurring at the Bay of
Fundy in Eastern Canada.
The position of the sun and the moon with respect to each other determines the effect on tidal
range. When the sun and the moon are aligned in the same plane or opposite each other, they
reinforce each other’s gravitational pull and cause a spring tide.
Spring tides which occur at new and full moons, have a higher than normal high tide and a lower
than normal low tide. When the sun and the moon are at right angles to each other, they cancel
each other’s gravitational pull, and the high tides are lower than normal and the low tides are
higher than normal, this is called neap tides. Neap tides occur at quarter and three quarter
Tides are very important to the organisms that live between high and low tide marks. These
organisms need to adapt to alternating periods of wet and dry. Some organisms’ reproductive
cycles are synchronized with spring tides. For example, along the coast of California, a fish called
the grunion spawns only at spring tide.
Sun- Earth- Moon System
January 27, 2010
The sun is the center of the solar system, which consist of the sun and all the orbiting planets,
their moons, and all of the other orbiting materials including comets and asteroids. It formed
about 4.5-5.0 billion years ago as a small yellow star from one of the arms of the Milky Way
Galaxy. As the sun orbits around the center of the galaxy, which is a large disk of stars rotating
around a common center, its planets and their respective moons orbit around the sun.
Rotation is the spinning motion of a planet or moon around a planet. The revolution of Earth
around the sun, or a moon around the planet. The revolution of Earth around the sun in its
orbit, or path it follows around the sun, defines a year.
Other planets have different orbital periods, the time it takes to make one complete trip around
the sun, Mercury takes 88 days to orbit around the sun, the shortest time of all planets. Orbital
or revolutional periods take longer; the farther they are from the sun. Pluto takes 248 years.
As Earth rotates around the sun, it is rotating or spinning about its own axis. The spin axis or
rotational axis of Earth is tilted 23.45 degrees. It is this tilt that determines the amount of
daylight and darkness in a solar day.
The tilt of Earth’s rotational axis also produces the seasons. During the summer, the northern
hemisphere of Earth is tilted toward the sun. During the winter, the southern hemisphere is
tilted toward the sun, and our winter occurs when Earth is at perihelion, or in the part of its
orbit that it is closest to the sun.
Seasons in the Northern Hemisphere
Date Season Sun’s path across sky Length of day and
June 20, 21 First day of summer Sun follows highest Longest period of
path across sky daylight. Shortest
period of darkness
September 22, 23 First day of fall Sun follows path Daylight and darkness
midway between of equal length (12
summer and winter hours each)
December 21, 22 First day of winter Sun follows the Shortest period of
lowest path across light. Longest period
the sky of darkness.
March 20, 21 First day of spring Sun follows path Daylight and darkness
midway between equal length ( 12
summer and winter hours each)
Moon and Lunar Cycle
January 28, 2010
The revolution of the moon around Earth defines the lunar month. The length of time it takes
for the moon to orbit the Earth is called period.
Periods of the moon and planets may be measured using two different systems: sidereal and
The sidereal period is the time it takes for a body like the moon or Earth to complete a trip, or a
360 degrees rotation around another celestial sphere. The sidereal period of the moon is 27.3
days, that is, it takes that long for the moon to make a complete trip around the Earth.
The synodic period is the time it takes the moon to complete all the phases of its cycle. The
synodic period is 29.5 days.
The different stages or phases of the lunar cycle of the moon as it revolves around Earth are
produced by the sun-Earth-moon system. Phasing is the gradual change in the appearance of
the moon as viewed from Earth. These changes begin with the new moon. As the moon begins
to reflect sunlight toward Earth, it becomes a waxing crescent moon. (During waxing phases of
the moon, the lighted side of the moon becomes increasingly visible. Gibbous moons are lunar
phases between first quarter and full moon). The waxing crescent moon is followed by a first
quarter moon, a waxing gibbous moon, and a full moon. The lighted portion of the moon, as it
is seen from earth then decreases, going from full moon to third quarter moon, wanning
gibbous, wanning crescent, and returning to new moon.
At the new moon phase, the moon is located on the same side of the Earth as the sun, so that
no light is shining on the side of the moon facing the Earth. When the moon is in this position,
no sunlight is reflected toward the Earth, so all we see is darkness. As the cycle continues, the
first waxing crescent moon appears as more and more light is reflected toward Earth. The word
waxing means gradually adding light to an object, like adding wax to a candle.
At the first quarter moon half of the lunar surface is illuminated. AS the moon continues to
move in its orbit, the waxing gibbous moon is aligned so that three quarters of the lunar surface
reflects light toward Earth. At full moon, the moon is located on the side of the Earth opposite
to the sun. The waning gibbous moon shows only three quarters of its illuminated surface. The
third quarter moon occurs when the moon and the sun are at a 90 degrees angle with Earth, and
half of lunar disk appears illuminated. Near the end of the cycle, the moon appears as a waning
crescent moon and then returns to new moon.
During full and new moons, the sun and moon align so that from a standpoint on Earth, the
moon blocks light from the sun and produces a solar eclipse, that is, the shadow of the moon
passes across the surface of Earth.
A lunar eclipse occurs at full moon when Earth blocks the light from the sun from reaching the
moon, or the moon passes through the shadow of the Earth. An eclipse occurs only when the
moon’s orbital plane intersects the Earth sun plane.
The orbits of planets, moons, and comets have elliptical shape. The ellipse depends on the
eccentricity or elongation, most planets have orbits almost circular, but for example Pluto is very
elliptical. An elliptical orbit means that the planet isn’t always at the same distance from the
sun. When the planet is closest to the sun, it is to be in perihelion, which is when it travels
faster, when the planet starts going away from the sun, it starts to slow down, and when it is the
farthest, its velocity is at the minimum, and gets pull by the sun again. This constant speed
change and direction is called acceleration. When the planet is the farthest from the sun is
called aphelion. When the moon is closes to the sun is called perigee, and when the moon is at
a greater system is called apogee.
Ocean currents, moon-Earth system
January 29, 2010
1. Describe the difference between a density current and a surface current.
2. Why are the tides 50 minutes later each day?
3. What causes the seasons on Earth?
4. Analyze the factors that contributes to an hurricane
5. Compare a solar and a lunar eclipse
Origin of the Solar System
February 1, 2010
Our solar system consists of the sun and everything that revolves around it. This includes Earth,
eight planets as well as moons, stars, and other heavenly bodies. Most of the mass of the solar
system is contained within the sun. The Jovian planets named after Jupiter, which are Jupiter,
Saturn, Uranus and Neptune contains most of the remaining mass of the solar system.
Our solar system was formed by a solar nebula. A nebula is a large cloud of dust and gas in
space. Our solar system started forming when this nebula started to spin; this spinning dust and
gas began to collapse and formed a protostar. As the protostar continued to collapse, it also
began to spin faster and faster, and the solar nebula flattened into a disk shape and contracted
under its own gravitational pull. As the density of the nebula increased, the gravitational
contraction also heated the nebular material until protostar began to grow.
A planet formation involves three processes:
1. Gravitational Collapse- forms planet sized clumps of material by compressing matter to a
point that it continues to attract more and more matter.
2. Another process accretion occurs when small particles collide and stick to each other. These
in turn, stick to larger particles and eventually form planet-sized pieces.
3. Condensation starts at the atomic or molecular level and builds larger and larger particles.
When the protostar begins to clamp to form larger bodies, it forms planetesimals, which are a
few hundred kilometers in size. The planetesimals, in turn, collide and stick together to form
planet-sized masses or protoplanets. The protoplanets in our solar system continue to collide,
stick together and break apart forming larger and smaller bodies to accrete more material from
Angular momentum is the tendency of bodies to keep spinning.
Planets of the Solar System
February 2, 2010
The asteroid belt between Jupiter and Mars divides the planets of our solar system into two
groups: the inner planets and the outer planets.
The inner planets: Mercury, Venus, Earth and Mars. They are closer to the sun. They are also
called terrestrial planets because they have rocky crusts overlying denser layers of rock.
Distances in the Universe are measured by AU. 1 AU is 150 millions of Km.
- Mariner 10 investigated Mercury.
- Mercury looks like the moon, full of craters.
- Mercury has a small orbit around the sun, so it is never far from it. It is 0.4 AU from the sun.
- Mercury surface is very hot, 670K, but at night drops at 103 K.
- Mercury spins very slowly on its axis. One day on Mercury is 176 days on Earth
- Mercury has no atmosphere or water.
- It is 0.7 Au from the sun
- Visited by Mariner 10
- It has thick layers of clouds made of carbon dioxide, which makes Venus very reflective.
- Venus spins in the opposite direction of other planets and the sun.
- One day in Venus is 117 days on Earth.
- Venus does not provide an environment that can support life.
- Venus is hot and contains large amounts of sulfuric acid.
- The atmospheric pressure of Venus is 90 times more than pressure on Earth.
- Venus’s thick atmosphere prevents the release of energy by radiation, producing high
temperatures and the “greenhouse effect”.
- Earth is the third planet from the sun.
- We measure the other planets according how are positioned from Earth.
- It is 1 AU from the sun
- It revolves on its axis one time a day.
- It is the only planet that can sustain life.
- The only planet with large amount of water in three states: solid, liquid and gas.
- It has large amount of liquid water in the surface, when water freezes, ice floats, so it can
preserve life below the surface of ocean.
- All the water on Earth’s surface, solid and liquid, is called the hydrosphere.
- The atmosphere protects life from UV light, the ozone layer is the protection
- The atmosphere is composed of 78% N, 21% O and 1% carbon dioxide and other gases.
- Mars have been visited by probes Viking I, Viking 2, and Pathfinder with a rover Sojourner
which explore the surface.
- Mars has polar icecaps of carbon dioxide that contains small amount of frozen water
- Mars has a thin atmosphere formed by carbon dioxide.
- Mars is 1.5 AU from the sun
- It has two moons Phobos and Deimos
- It is 11% the mass of Earth.
- Its orbit is 1.9 years, and its day is 24.7 hours
- Mars is very cold, its surface temperature ranges from 144 K to 300 K
- Mars has the largest volcano in the solar system. Olympus Mons
- The surface is iron oxide that is the reason why it looks red.
- It has frequent gas storms.
The Outer Planets: Jupiter, Saturn, Uranus, Neptune and Pluto. The outer planets are larger
than the inner planets. . They have satellites, rings and thick-gaseous atmospheres. They are
called gas giants.
- The largest planet in the solar system
- 5AU from sun
- One day in Jupiter is ten hours in consideration with Earth
- Jupiter’s atmosphere has large swirling clouds of hydrogen, helium, methane and ammonia.
- It has huge storms, one of this storms is the Great Red Spot which is an hurricane bigger
than twice the Earth
- It has 61 satellites, four were name by Galileo: Io, Europa, Ganymede, Callisto.
- Io has active volcanoes and a thin atmosphere
- Europa has water below the icy surface.
- Has 31 satellites
- 95 times the mass of Earth
- Takes 29 years to orbit the sun
- A day in Saturn is 10.7 h
- It is made of gas, and rotates faster at the equator and slower in the poles.
- It has a spectacular system of rings, made of tiny particles of dust, rock and ice.
- It radiates 3 times the energy that receives from the sun.
- Helium in its outer layers is condensing and falling inward. The helium at the center is
- Smaller than Saturn and Jupiter
- The methane in the atmosphere gives the atmosphere a bluish color.
- 19 AU from Sun
- Takes 84 years to orbit around the sun
- It is like 14 Earth masses
- Uranus day is 17 h
- Extreme seasons because of its tilt of 98 degrees
- Few clouds, and wind
- About 58 degrees
- Similar to Uranus
- Bluish color because of methane in atmosphere
- 17 Earth masses
- 164 years in orbit sun
- A day is 16 h.
- Distance of 30 AU
- No sure if it is a planet.
- Moon Charon
- Very elliptical orbit, it was captured by gravity
- Sometimes is not the farthest planet from the sun
- Takes 248 years for orbit the sun
- 40 Au from sun
- 0.002 the mass of Earth
Moons, Planets, Stars
February 3, 2010
A moon is a celestial body that is in orbit around a planet. Our moon orbits the Earth and it is made of
same material than the Earth. Although there is only one natural moon, there are many artificial
satellites or artificial moons in Earth orbit.
Other planets have moons too. Galileo in 1632, using a telescope, discovered other moons around other
planets, among them, Jupiter’s largest moons.
Jupiter’s moons are Io, Europa and Ganymede, and they have icy surfaces, Europa is considered the
most likely to have water.
Major Planetary Moons
PLANET NUMBER OF MOONS
The planets closest to the sun have higher density and rocky composition. The inner planets: Mercury,
Mars, Earth and Venus are grouped together because they have similar composition.
The outer planets: gas giants or Jovian planets: Jupiter, Uranus, Saturn, and Neptune are less dense and
much larger in volume. Pluto is the only one in its own category due to its icy rock composition, it is
tilted, and highly elliptical orbit.
There are many objects in the solar system that are not planets or moons, those are asteroids.
Asteroids are large chunks of rocks. Most asteroids orbit the sun in the asteroid belt between Mars and
Jupiter. The asteroids vary in size and composition, and the majority is rocky or stony material as
The carbonaceous chondrite asteroids are very dark in color, and similar to oil shale here on Earth
Metallic asteroids are very rare. They have high concentration of metals, such as iron.
Asteroids are thought to be made of material left over from the formation of the solar system that
collected due to the strong gravitational pull of Jupiter. Asteroids are not fragments from a destroyed
planet, because there is too little material present. There are asteroids that orbit Jupiter and a few that
have elliptical orbits around the sun. Some of these asteroids are “earth crossing”, which means that
they intersect with Earth’s orbit. If an asteroid were to hit Earth, it would cause a great deal of damage.
Comets orbit the sun and have elliptical orbits. Comets are dirty snowballs. They are mostly water and
methane ice mixed with sand, rocks and gravel. They originate at about 150 AU (AU= 1.496x109 km)
Comets travel at high speeds towards the sun, turn around the sun and then head back to the outer part
of the solar system. When they orbit around the sun, they are influenced by Jupiter’s gravitational pull,
which alters their courses. Some comets turn around the sun too close and then, they are torn apart. As
they approach the sun, they begin to vaporize and produce a long tail composed of dust and gas. This
tail interacts with the solar magnetic field, which turn into a glowing ion tail. The passages of Haley’s
comet every 76 years past Earth has been observed for many centuries.
When Earth passes through the debris left along the path of a comet, we experience meteor showers.
Meteors occur as streaks of light when pieces of rocky material (meteoroids) enter the atmosphere and
het up due to air friction. When they strike Earth’s surface, they are called meteorites. Meteorites
debris has been found in Antarctic. Some meteorites thought to have originated on Mars.
To express distance in the Universe, we use AU or light years what is the distance light can travel in a
year, while Astronomical Unit (AU) is the average distance between the Earth and the sun is 150,000,000
Ground based telescopes are the ones that make more of the Universe observations. Telescopes can be
used to observe many different wavelengths or light, including visible, infrared, millimeter radio waves
Most telescopes are reflecting telescopes that use mirrors to reflect and focus light. These telescopes
are very large.
Radio telescopes use reflectors and receivers to scan the sky for radio waves. They are also large; these
telescopes have antennas on a Y shape set of rails to adjust the size of the telescope opening. Images
from ground telescopes have been improved using active optics, very long base interferometry connects
radio telescopes all over the world to act as a single telescope and there is image processing using
Some waves of light, for example, ultraviolet and X rays do not pass through the atmosphere and must
be observed with telescopes that are in space aboard rockets, satellites or space shuttle. Today, we also
have in orbit the Hubble Space Telescope that provides a view of the objects that pass through Earth’s
atmosphere. The Hubble studies the formation of galaxies.
Astrophysics use models in computers to study observations from space.
Astronomers use satellites and probes to study space, probes have gone to the moon, Venus and Mars.
February 4, 2010
Our sun is the closest star and it is only one of the billions of stars. Starts are very large balls of hot gases
that are in equilibrium with the force of the gravity trying to compress and contract them, while at the
same time, nuclear fusion reactions in their centers are trying to push outward and expand them.
During most of the star’s life, hydrogen is being fused into helium, releasing energy in form of heat and
electromagnetic waves. These waves include ultraviolet, visible and infrared light as well as X rays and
radio waves of varying length.
Stars have different colors: red, blue, yellow and orange. The color of the star is determined by different
factors. The first is the size of the star. Larger, fast burning stars appear blue color because of the hot
surface temperature. Small stars appear reddish, because they have lower temperatures in the surface.
If we look at the light coming from a star through a spectroscope, the light is separated and broken
down into its component colors. We see both brightly colored lines and black lines where there is no
color. These characteristic line emission spectra show the elemental composition of the star.
The luminosity of a star is plotted against its surface temperature in a graph called Hertzsprung-Russell
diagram; the highest temperatures are on the left of the graph and the lower temperatures on the right.
By plotting more and more stars on the diagram, a star pattern is shown. Most stars fall on a curved
diagonal line running downward. Stars on this line are called main sequence stars. They are in stable
equilibrium, fusing hydrogen into helium to perfectly balance the inward gravitational force trying to
compress and shrink them. This balance is created as hot fusion reactions in the cores of these stars
push outward, trying to expand the outer layers and the star itself.
Several other groups of stars also appear as grouping on the H-R diagram. In the upper right are the red
giants; at the left side at the top, the blue giants are grouped together. These are both very hot and
large stars. Below the main sequence and from the middle to the lower right are the white dwarf stars.
All of the stars not on the main sequence do not fuse hydrogen into helium; they use other elements to
provide fuel for the fusion of the reaction.
The Beginning of a Star
A star is born when a large, cold cloud of dust and gas condenses and collapses on itself. Once a core
material has formed, it continues to collect dust and gas into itself by gravitational contraction. Its
gravitational pull increases as the amount of mass increases. As this accretion continues, the central
material heats due to friction and compression. Material is added rapidly to overcome the growing
outward pressure from heating and compression. The inertial of the material falling into the protostar
helps to continue the condensation process. Initially, heat and light given off by a protostar are
produced as a result of gravitational contraction. Eventually, the core heats and compresses to the
temperature and pressure where nuclear fusion starts. As the star lights, it fuses hydrogen into helium,
using the proton-proton cycle and moves onto the main sequence of H-R diagram. The star expands and
sheds the outer material that will become its planetary system. The spin of the system will concentrate
the leftover materials into a disk where planets will form.
Another way of forming stars is through a supernova, which is the implosion of a star. When a
supernova explosion occurs, it creates shock waves in clouds of dust and gas. This forces the materials to
increase in density and begin gravitational contraction. The result is the formation of a protostar, which
is a star that produces light using gravitational attraction. All stars begin as protostars; their color
indicates size and temperature. The life span of a star is inversely proportional to its mass. The more
mass that a star has, sooner it will be consumed. Very luminous blue giants only have a life span of
20,000 years; a red small star has a life span of 20 billion years.
The ending of a Star
The end of the life of star depends on its mass. A star of about the same mass of the star will contract
and it will consume its hydrogen fuel. A layer of hydrogen near the core starts to fuse as an expanding
shell. When this happens, the star expands outward from the hot expanding gases in the burning shell.
The outer layers of the star will expand so that the planets of the solar system become part of the
interior of this red giant star.
The core the star continues to increase its temperature and pressure, compressing the matter inside it.
The matter in the core is compressed until degenerates. Degenerate matter forms when the ionized
atoms’ electrons and nuclei are packed together as tightly as possible, with the electrons all forced into
the lowest energy levels of the atoms. In normal matter, much of the volume of an atom is empty space.
In degenerate gases, there is no space between electrons and their nuclei.
The degenerate helium in the core of the red giant star will continue to heat until it begins to fuse into
carbon. The star pulses and sheds its outermost layers into space as a planetary nebula, an expanding
shell of hot glowing gas. This leaves behind a white dwarf star glowing white hot due to extreme
temperatures. The white star is still composed of degenerate matter with only the repulsion of its
electrons keeping the star from collapsing further. This also gives it the name of electron star. Without
insulation in the atmosphere, the white dwarf will cool into a black dwarf, while still maintaining its
Life of a Star
The life of a star three to five times the size of the sun differs in several ways.
First, it has a shorter main sequence life span. Once all of the hydrogen is converted into helium, the
helium in the core of a star this size does not degenerate. Hydrogen is used fast, with a fast rate, and
the star shrinks. New hydrogen falls into the core, Ignites, and forms a shell that burns outward and
expands the star into a red giant. The red giant eventually shrinks and expands into a red giant for a
Later events in the life of a star depend on its core mass. The star may shed the outer layers forming
stellar or super wind s its atmosphere boils into space. This forms a planetary nebula and a white dwarf
core. However, if the core is large enough (about 1.4 the mass of the sun) it will develop a degenerate
carbon core that fuses rapidly. This rapid carbon core fusion blows the star apart in a supernova
explosion. The initial implosion crushes the core. Electrons, protons and neutrons are crushed into each
other, leaving a core made of degenerate neutron gas. The star is now a neutron star or pulsar. The
neutron star has a radius of about 10 km with a mass of up to 3 solar masses. As the star remnant spins
faster and faster, it contracts into smaller and smaller sizes. The gravitational pull of this neutron star is
greater than that of the original star because of its concentrated mass. Escape velocity, or the speed
required to pull away from the gravitational pull of another object, is 80% of the speed of light.
A larger star of 6 times the mass of the sun burns its fuel very rapidly. It is also capable of generating
high temperature and pressures that expand the star more and more rapidly, fusing elements of higher
and higher atomic numbers. Less and less outer pressure is produced each atomic fusion reaction until
the outer parts rush inward. The star collapses into the core, crushing the degenerate mass together;
the neutrons are crushed together, overpowering the repulsive forces. The core of the star is crushed,
the volume becomes zero, and its mass and density become infinite. The star becomes a black hole. The
escape velocity is now much larger, so the light cannot escape.
Many of a star belongs to a binary system, the sun is an exception. In this binary system, two stars orbit
around each other. . Most often both stars are different from each in terms of age, size and masses.
When two stars rotate around each other, the center (barycenter) is the center of their masses. The
relative masses of each star determine the barycenter. Sometimes binary system stars interact with
each other and produce optical binary systems. Optical binary systems are aligned so that the light
coming from them varies according to alignment.
Constellations are the most known group of stars. They are the pattern of stars that we see from Earth.
As binary stars are grouped together, more stars can be grouped or clustered together like the
constellations. There are different types: Open or galactic clusters, like the Pleides that can have up to
10 stars per cubic light year. Globular clusters can have 100 stars per cubic light year. The average star
density in the galaxy depends on location. Stars near the center, are closer together, less than a light
year apart. Stars in the outer spiral arms have more distance among them. Stars in the galactic halo,
which is the cloud of hydrogen around the galaxy, has more distance among them. Our galaxy is 120,
000 years across and 12,000 light years thick. The nucleus, a bulge is 30,000 light years with a black hole
in the center.
Stars, galaxies, telescopes…
February 5, 2010
1. Classify the planets as inner or outer, and compare the composition of inner and outer planets.
2. Describe the change in brightness of a star as the distance from the observer increases.
3. What unit of measure is suited to measure the distances between galaxies? (hint: there are two
of them) Define them.
4. What advantages does the Hubble Space Telescope provide in the study of galaxies?
5. What happens to the mass of the star in a fusion reaction?
Chemicals of Life
February 8, 2010
Living things have and organize in cells, tissues, organs, and organisms. Living things are made of
compounds, which are used to produce energy, and that energy helps the organism to regulate
and maintain the balance of its internal environment (homeostasis).
Metabolic energy helps the organism to grow, respond to stimuli, and eventually reproduce. S
organisms grow and their numbers increase, the best adapted survive and their accumulated
adaptation results in evolution, or change through time and space.
There are six elements that make up 99% of the mass of living thing: Carbon, Hydrogen, Oxygen,
Nitrogen, Phosphorus and Sulfur.
Carbon ©- is an organic compound that makes up carbohydrates, lipids, proteins and nucleic
acids. Carbon- C- can form different types of bonds, and the molecules can have a variety of
shapes. Carbon has four electrons in the outer shell. This allows this element to form single,
double, and triple bonds. They can form straight chains, branched chains and rings too.
Organic compounds may be large macromolecules. Macromolecules are large polymers.
Polymers are large chains of similar repeating units. These subunits are called monomers. For
example, cellulose is made of repeating subunits of glucose.
Carbohydrates, proteins and nucleic acids are all polymers. The polymers are formed by a
chemical reaction called condensation. Condensation reactions bond smaller molecules
together by removing an H+ ion from one molecule and an OH- group from another. This bonds
the two molecules together and releases a molecule of water. This reaction is called
Polymers split apart by a reaction called hydrolysis. OH- and H+ join to form a molecule of
Carbohydrates include sugar and starches. Most of them consist of rings of carbon atoms.
Molecules that have same number of kind of atoms by different structure are called isomers.
For example the two glucose molecules at the beginning of lesson.
Monosaccharides are made of simple molecules. Example: fructose, glucose and ribose.
Disaccharides are made of bigger molecules; they are made of two monosaccharides joined
together by a condensation reaction. Example: maltose, sucrose, lactose
Polysaccharides are referred as complex carbohydrates because they are made of many
subunits of monosaccharides together: cellulose, starch and glycogen.
Carbohydrates are the main energy resources of our body. Although, monomers are a quick
source of energy. Starch, a polymer, provides a longer source of energy over a long period of
In plants, glucose is stored as starch; in animals glucose is mainly stored as glycogen. Glycogen is
stored in the liver and muscles, and it is converted back to glucose through respiration.
Cellulose is made of subunits of glucose, digested by cows and other ruminants and it is very
important in plant cell, because provides the structure of the cell wall in the plant.
Lipids, Proteins and Nucleic Acids
February 9, 2010
Fats, waxes, steroids and phospholipids are lipids. They are made of C, H and O. They are nonpolar and
non soluble in water.
Lipids consist in long chains of H and C. The energy in the C-H bonds allows them to store more energy
than proteins or carbohydrates. Lard and peanut oil are fats composed of large chains of C and H called
The physical properties of the fats are determined by the number of single and double bonds in the fatty
acid chains. Lard for example, is a saturated fat without double bonds. The absence of double bonds
allows them to be solid at room temperature. Unsaturated fats as olive oil has double bonds in their
structure, lipids with double bonds in their structure are liquids at room temperature. If an unsaturated
fat has many double bonds, it is polysaturated. Polyunsaturated fats are also healthier to eat because
the y does not contribute to heart and circulation disorders.
Lipids provide protective padding to organisms and thermal insulation. They help to regulate body
temperature in cold weather. Waxes form protective covering on fruits and leaves. Steroids, which are
different from other lipids because they are ring compounds, include steroids and sex hormones.
Phospholipids are major part of cell membrane. They are made of glycerol molecule bonded to two
nonpolar , fatty acids and a polar phosphate group.
They are large molecules composed of smaller subunits or building blocks called amino acids.
There are 20 different amino acids, but all of them have two things in common: an amino group (-NH2)
and a carboxyl group (-COOH).
Proteins are formed by the bonding of amino acids in condensation reactions. The function and
complexity of proteins are determined by the types and numbers of amino acids.
A protein’s function also depends of its shape. One important type of proteins is enzymes. Enzymes have
an active site and a substrate that fits like a lock and a key. If the enzyme’s shape is altered, its function
should be altered. This is why enzymes and other proteins may be permanently inhibited by
denaturalization or structural damage by heat or ph extreme.
Nucleic Acids, for example, RNA and DNA are polymers made of smaller subunits called nucleotides.
Each nucleotide is made of a sugar, phosphate group and one nitrogen base.
The sequence of DNA bases constitutes the genetic code. By the 1900’s it has been determined that the
DNA had genetic material. The structure of the molecule of DNA was discovered by James Watson and
Francis Crick. The triplet code, or the sequence of three base pairs on the DNA molecule, was found to
be the basis for inheritance and genetic code.
The Watson and Crick double helix DNA molecule is made of nucleotides. The sugars and the
phosphates are outside a spiraling later, where the nucleotides are inside and the pairing of adenine is
always with Thymine, and guanine is always with cytosine. Hydrogen bonds hold the bases and the
double helix structure together.
This complementary base pairing is the basis for DNA replication. If a single strand of DNA is cut,
CGGGTTAA, the other half will be GCCCAATT due to complementary base pairing. When the DNA
molecule untwists its double helix, exposing the bases, new nucleotides will pair and dehydration
synthesis will remove water molecules from between the nucleotides, bonding them together.
Differences between DNA and RNA
double helix simple helix
Nitrogen base Thymine Nitrogen base Uracil
Sugar- deoxyribose Sugar- Ribose
One type of DNA 3 types of RNA: messenger RNA, ribosomal RNA and
February 10, 2010
The first microscope was created by Anton van Leeuwenhoek in 1600’s. Then Robert Hooke, using
another crude light microscope was able to observe the spaces in a cork bark and called cells, because
remained him to the monk cells where they lived. Later in 1830’s the cell theory was proposed by
Theodor Schwann and Matthias Schleiden stated that all plants and animals were made of cells.
Today, the cell theory states that cells are the basic units of structure and function in all living things and
all cells come from preexisting cells.
Since the invention of the first light microscope, microscopes have done much improvement. Today,
scientists use electron microscopes, which magnify images by passing a beam of electrons through
Cells are classified as prokaryotic or eukaryotic.
Prokaryotic cells lack nuclei and their DNA is not separated from the rest of the cell by any membrane.
Bacteria and cynobacteria are prokaryotic, their structure is less complex than eukaryotic, and some
fossils called stromatolites indicate that blue green algae were among first organisms to inhabit the
Eukaryotic cells have their nuclei and other organelles bound by membranes. They are more complex
than prokaryotic cells. Protists, plants, animals and fungi are eukaryotic.
All cells are bounded by a membrane on the outside. The cell membrane is a bilayer of
phospholipids with proteins distributed inside. Other substances as cholesterol or
carbohydrates are present. Cholesterol stabilizes the membrane and carbohydrates help to
recognize other cells. The composition and arrangement of phospholipids and carbohydrates
make most cell membrane selectively permeable. That means that the membrane allows some
substances to pass to the cell and others not.
The nucleus contains the genetic material deoxyribonucleic acid (DNA). DNA is organized into genes,
which are the basic units of heredity. The genes and their DNA form long strands that during cell
division coil and shorten to become chromosomes. When the cell is not dividing, the chromosomes
appear to be ropy, stringy strands clumped together called chromatin.
Because the DNA of the nucleus determines the functions and behavior of the cell, the nucleus is called
the control center of the cell. The nucleolus lies inside the nucleus; it
makes ribosomes, which are the sites of protein synthesis.
The mitochondrion is a rod shaped structure surrounded by a double membrane that is
infolded and serves as the site of the energy reactions of the electron transport system. The
infolding of the double membrane allows for greater surface area on which chemical reactions
can occur. As electrons move through the double membrane, the electron transport system
produces adenosine triphosphate (ATP). The double membrane also accumulates protons from
cell respiration and uses the proton gradient to produce more ATP. ATP is the energy molecule
of the cell. The inner matrix of mitochondrion is the site of Krebs cycle reaction.
It is made of folded membranes.
Rough Endoplasmic Reticulum contains ribosomes, synthesizes, stores and transport proteins.
The ER is part of a larger membrane system that connects Golgi apparatus and nuclear and cell
membrane. This membrane system increases the cell’s surface area to volume ratio involving
the cell in a more efficient transport of oxygen, nutrients and waste material.
Cell Structure and Function
1. Nucleus- Control of cell activities
2. Mitochondrion- Energy production
3. Ribosome- Protein synthesis
4. Golgi Apparatus- Assembles, sorts and transports cell products
5. Rough Endoplasmic Reticulum- Produces, stores and transports proteins
6. Smooth Endoplasmic Reticulum- Produces and stores lipids
7. Lysosome- Digest old cells, microbes and food
8. Vacuole- Storage, plant cells, increase volume and size of cell
9. Cytoskeleton- Supporting framework of cell, locomotion
10. Cilia and Flagella- Locomotion, moving of materials
11. Chloroplast- Site of photosynthesis
12. Cell membrane- Protection of cell; regulates entry and exit of materials. Maintains integrity
13. Centriole- Animal cells, makes cell division.
14. Cell wall- Plant, bacterial and fungal cells; support
Differences between plant cell and animal cell
1. Cell wall: the plant has a cell wall to give support and protection to plant.
2. Plant cell has chloroplasts that form saclike structure called thylakoids, there are
important for light dependent reaction of photosynthesis.
3. The vacuole is very prominent in plant cells. Storage of water and other substances
allows the plant to give plant cell volume.
4. The plant cell lack centrioles, which assist in cell division.
February 11, 2010
Movement of Material across Membrane
Two types of movement across membrane
Passive Transport: it is driven by concentration gradient; it does not need energy,
always moves substances from higher to lower concentration.
1. Diffusion: Passive transport. Random movement of a substance from a
higher to a lower concentration. Example: smoke in air. When the particles
reach a point when there is not a difference in concentration, they reach
dynamic equilibrium. The difference between the high and the low
concentration is the concentration gradient. Gases, solids and liquids
undergo diffusion. Diffusion is also determined by the charges and sizes of
molecules. Smaller, uncharged molecules tend to diffuse across membrane
faster than charged and larger molecules.
2. Osmosis: It is a passive transport. It is the diffusion of water through the cell
membrane. The direction of its movement is determined by the
concentrations of materials (solutes) dissolved in water. Water tends to
move from areas of low solute concentration (hypotonic) to areas of high
solute concentration (hypertonic). When solutions are equal in concentration
(isotonic), there is not net gain of water molecules.
3. Facilitated diffusion: Requires a carrier molecule in the transport of
materials across membrane. It does not require energy, and moves materials
from high to low concentration. Movement of glucose across membrane is
an example of facilitated diffusion.
Active Transport: moves materials against concentration gradients that are from low to
high concentration. Sugars, amino acids, and ions move by active transport. The
sodium-potassium pump is an example of how ions are actively transported across
membrane. ATP is needed to transport K and Na ions.
Life molecules, cell, cell transport
February 12, 2010
1. Why is carbon a versatile element?
2. Compare the biological roles of proteins, carbohydrates and lipids
3. If there is a muscle cell, which organelle would you expect to see in large number?
4. Draw a plant cell and an animal cell. Describe the differences
5. What is the main difference between passive and active transport? Classify and
describe the different types of transport across a cell membrane
February 15, 2010
In all living things, energy is required to build tissues and carry out other life processes.
This energy comes from the breakdown of food in a process called respiration. All of the
chemical pathways and their chemical reactions are called metabolism.
Cell respiration is the breakdown of a glucose molecule. Chemical energy is stored in
the bonds of glucose molecules, and when the molecule is broken down; the energy is
released from its chemical bonds and is stored in the form of ATP. ATP stores and
releases energy for chemical reactions and most cells activities.
6CO2 + 6H2O + Light Energy = C6H12O6 + 6O2
In this reaction, glucose and oxygen are the reactants, and carbon dioxide, water and
energy are the products. The energy produced is in the form of ATP and heat.
Cell respiration has three stages: glycolysis, Krebs cycle, and electron transport chain.
Glycolysis occurs in the cytoplasm of the cell. It splits a molecule of glucose into two of
pyruvic acid. These reactions occur whether or not oxygen is present. Although this
process is not efficient, many cellular organisms use it to obtain energy.
If conditions are anaerobic (lack of oxygen), some organisms may convert pyruvic acid
into carbon dioxide and alcohol. This is called fermentation. Formation of yeast is an
example. Fungi, bacteria and human muscle cells produce lactic acid under this
conditions. Cheese and yoghourt are created by fermentation. In humans, lactic acid
buildup causes fatigue and cramps. When oxygen levels are restored, lactic acid breaks
down and the pain and fatigue go away.
The Krebs Cycle- is an enzyme-catalyze reaction. It is different from the glycolysis
pathway because it is cyclic, beginning and ending of same product. In nature, cyclic
processes are efficient and save energy. The krebs cycle occurs in mitochondrion of the
cell in the presence of oxygen.
The electron chain- is located within the mitochondrial membrane. This part of cell
respiration produces most ATP.
February 16, 2010
Plants take energy of the sun and store it in the food they make. This conversion of solar
energy into carbon compound is called photosynthesis. Organisms that make their own
food are also called autotrophs or primary producers. In the process of photosynthesis,
plants use solar energy to convert carbon dioxide and water into food and oxygen.
Most photosynthesis occurs in the leaves of the plants because it has the biggest
number of chloroplasts. The gases oxygen and carbon dioxide exit and enter through
openings on leaf called stomata. The reaction of photosynthesis is:
6CO2 + 6H2O + Energy C6H12O6 + 6O2
Carbon dioxide and water are reactants and glucose and oxygen are the products. These
reactions require the green pigment chlorophyll and occur in the part of the plant called
chloroplast. For the plant to make its own food, it has to trap the light energy in the
form of photon. To do this, the plant uses the pigment chlorophyll and a series of light
reactions called light dependent reactions. In these reactions, the photon of light
strikes a chlorophyll molecule and excites the electrons. The oxygen goes into the
atmosphere, and the protons and electrons remain in the system. The ATP is used to
run the next phase of photosynthesis the light independent reactions.
The light independent reactions use carbon dioxide to produce glucose. When the plant
produces more glucose than needs, the excess of glucose is converted into starch. The
rate of photosynthesis is affected by different factors. Chlorophylls only absorb blue and
red light wavelengths. Chlorophylls reflect green wavelengths that are why the plant
The photosynthesis is affected by:
1. Light intensity
2. Amount of carbon dioxide
3. Temperature- photosynthesis increase with temperature but over 95 degrees is too
high, and photosynthesis decrease.
4. Water- water is split during photosynthesis (photolysis) required in the light
February 17, 2010
The cell theory states that cells come from preexisting cells. Cells must divide when this
happens. Cell division is essential for growth, repair and reproduction and involves the
production of two identical daughter nuclei by the process of mitosis.
Mitosis is followed by cytokinesis, which is the division of the cell membrane and completes
the division of two new identical daughter cells.
Mitosis is part of the cell cycle, it is preceded by a preparatory phase where cell grows,
synthesize new organelles and DNA is replicated. After the cell has prepared for mitosis, it
begins to undergo distinct changes:
1. The nucleolus and nuclear membrane disappear
2. Chromosomes become distinct and shorten
3. The spindle apparatus, made of microtubules, begins to stretch across the cell.
4. The chromosomes are paired and called chromatids.
5. The chromosomes align themselves down the equator of the cell and split apart.
6. The spindle fibers pull them to opposite poles of the cell
7. Once the chromosomes reach opposite poles of the cells, the nuclear membrane
reappear and chromosomes uncoil.
8. Two identical cells are formed.
9. Cytokinesis follows mitosis, and in animal cells forms a shallow furrow that deepens
until the two cells are completely separated.
10. Cytokinesis is different in plants, a row of polysaccharides or cell plate forms down the
middle of the cell. New cell wall material is deposited along the cell plate. The two new
identical daughter cells are formed.
Mitosis is used as a mean of reproduction by single celled organisms. It is a form of asexual
reproduction that involves only one parent. Amoeba and bacteria use this type of
reproduction when they divide to form to daughter cells in binary fission. Asexual reproduction
is advantageous for these organisms because is fast and efficient. Because asexual
reproduction produces clones of original parents, it does not produce genetic variation.
Sexual reproduction involves the production of offspring by two parents. It requires the
fusion of nuclei from reproductive cells. When this occurs, the genetic material of one
parent fuses with the genetic material of the other parent. . All species of organisms
have their own characteristic number of chromosomes. For example the body has 46
chromosomes. So, in order for the chromosome number not to double with each
fertilization, the number of chromosomes in each sex cell must be halved. The process
for doing this reduction is called meiosis.
Meiosis is similar to mitosis. Preparation for meiosis begin with a doubling (replication)
of the cell’s DNA. The cell actually goes through two meiotic divisions, I and II with the
same events than mitosis. Unlike mitosis, however, an exchange of genetic material
occurs between pairs of homologous chromosomes. Homologous chromosomes are
matched pairs of chromosomes one from each parent containing the same information.
This genetic exchange produces variation in the daughter cell and in a new individual.
The increase in genetic variation increases the likelihood of survival of members of
February 18, 2010
The triplet code or the sequence of the bases along a DNA molecule determines the sequence of
amino acids in proteins. The TTT molecule translates the sequence of amino acids,
phenylalanine. There are more than 20 different codes for amino acids as well as codes for start
The nucleic acid RNA, or ribonucleic acid, is used in the process of moving DNA information to
the ribosomes of the cell to convert amino acids into proteins. RNA is different from DNA in
several ways: RNA has different sugar, ribose instead of deoxyribose. RNA is always single
stranded, and is shorter than DNA. The bases for RNA are different too; RNA has Uracil while
DNA has thymine. When writing RNA code one replaces the other.
Protein synthesis has two faces: transcription and translation.
Transcription: In the nucleus of a cell the DNA slightly unwraps, exposing the bases that will
code for a protein. Messenger RNA (mRNA) is constructed using the DNA as a template for
making the m-RNA codon. The mRNA codon moves from the nucleus of the cytoplasm of the cell
where the m-RNA attaches to a ribosome on the rough endoplasmic reticulum.
The next part of the process is the conversion of the m-RNA codon into a sequence of amino
acids. Another type of RNA, a small cloverleaf-shaped transfer RNA (t-RNA) contains the
anticodon or the reading section of three bases. On the other end of the t-RNA molecule there
are attached amino acids. This will be the amino acid bonded to a chain of other amino acids to
create protein. There are at least 20 kinds of t-RNA’s.
The m-RNA is held in place while the appropriate r-RNA anticodon aligns with its codon triplet.
Again it is complementary base pairing that reads the correct sequence e. The peptide bonds
are formed between the amino acids as the ribosomes move down the RNA complex releasing
the protein until the stop codon is encountered. Additional passes by more ribosomes make
more copies of the protein. These proteins may be used in the cell, or they may be transported
to other places to assume their active role as enzymes, structural proteins or antibodies.
It is the faithful replication of DNA code that is the most critical. Any mistake, error, or change
during this process leads to a mutation.
Any mistake or change in a chromosome will be copied and passed on a chromosomal mutation.
The cell has special enzymes that check and correct mistakes in DNA. If the mistakes or
mutations in the DNA are passed to genes, they may express themselves as inherited defects
like metabolic disorders or sickle cell anemia. Sickle cell anemia is due to just one amino acid
substitution in the hemoglobin molecule. The change in the protein chain of the hemoglobin
molecule. The change in the protein chain of the hemoglobin molecule affects the shape of
blood cells. We can recognize that many diseases like phenylketonuria (PKU) and sickle cell
anemia are due to one misshaped protein or enzyme.
Cell reproduction, protein synthesis, energy transfers, photosynthesis
February 19, 2010
1. Compare photosynthesis and cell respiration. Diagram and explain both processes in your
2. Diagram the movement of energy from sunlight to glucose in the process of photosynthesis
3. Describe how mitosis differs from meiosis
4. Sickle cell anemia is due to an abnormal form of hemoglobin. This abnormality is due to a
substitution of one amino acid in each of its protein chains. Explain how this substitution of
amino acid could have occurred.
5. Compare hypotonic, isotonic and hypertonic solutions.
February 22, 2010
Gregor Mendel discovered the key to understanding inheritance while growing pea plants in a
garden. He realized that certain characteristics or traits of organisms could be inherited. He also
concluded that the presence or absence of these characteristics depended on the action of a
pair of hereditary characters or genes. One member of each pair is determined by the father
and the other by the mother. Mendel also discovered that genes may have several forms or
In the pea plant, the height of the plants was short or tall. Mendel reasoned that there were
three ways the two factors could express themselves as pairs. TT, Tt and tt (letters were used to
TT- tall individuals
Tt- also grew tall
Genes with the short characteristic were recessive. They appeared in the short form when they
were not paired with T. Genes with the tall characteristic were dominant.
The two letters used to represent an offspring’ s genetic makeup is the genotype. The
phenotype is the appearance of the organism. For example, the height of Mendel’s pea plant
was part of the phenotype, produced by the genotype.
The trait that always shows itself is the dominant trait (T). When alleles of a pair are the same,
they are homozygous. TT and tt are homozygous. The alleles Tt are heterozygous. When a
dominant allele T is paired with a recessive allele t, the recessive trait gets hidden by the
dominant trait. The only time the recessive trait can show itself it is when it combines with
another like itself.
TT x Tt – all of them will be tall.
Crossing two pure breed individuals TT x tt, the results will be TT- 25%, Tt 50%, and tt- 25%. A
punnet square is shown all the possibilities of the cross involving only one trait.
T TT Tt
t Tt tt
Mendel also worked with more than one trait of pea plants.
RY Ry rY ry
RY RRYY RRYy RrYY RrYy
Ry RRYy RRyy RrYy Rryy
rY RrYY RrYy rrYY rrYy
ry RrYy Rryy rrYy rryy
R is round seeds – dominant Y is dominant color yellow
R is wrinkled seeds- recessive y is green color –recessive
Yellow round seeds 9/16
Yellow wrinkled seeds 3/16
Green round seeds 3/16
Green wrinkled seeds 1/16
February 23, 2010
1. There can be more than two alleles for a particular trait. This is called multiples alleles. Our
system of blood groups shows this type of inheritance. The three alleles are A, B, and O,
which in different combinations can produce the blood groups. The O group is recessive.
When group A joins group B, the produce the group AB because neither allele dominates
the others. They are co dominant
A AB AO
O BO OO
Another type of inheritance is incomplete dominance, where each allele has an equal effect on
the phenotype. When tall plants are joined to short plants, produce an intermediate tall plant.
Polygenic inheritance occurs when three or more pairs of genes act together to produce a single
characteristic. In humans skin color and height are polygenic. These do not produce the all or
non inheritance but a gradual blending.
Sex determination is due to the presence or absence of Y chromosome. When combined with X
it produces males. X and Y chromosomes are called sex chromosomes. There are 23 pairs of
chromosomes in humans, 1 is sex chromosome, and the other 22 chromosomes are called
autosomes. When genes or alleles occur on sex chromosomes are called sex linked. For
example red- green color blindness and hemophilia are sex linked.
The gene pool of a species id the key to its ability to adapt to changing environmental
conditions. New genes are produced by mutation and can be passed to next generation. AS
recessive genes, these are most often hidden by the normal member of the gene pair. If the
recessive gene proves to be an advantage either in the heterozygous or homozygous condition,
it will be pass to next generations. It is a disadvantage, it will disappear or it will be eliminated
by death or non reproduction. For example Down syndrome adults cannot reproduce.
Survival of the species depends on the diversity of the gene pool. The larger and more diverse
gene pool the better, since the odds improve that a species can adapt rapidly to a changing
environment. Genetic diversity also depends on a population having a wide geographic range
where immigration and emigration of individuals and their genes are possible. These new
combinations of genes help diversify the whole population.
It is also important that an ecosystem has a diverse group of species within in. It is the genetic
diversity of all organisms in the ecosystem that is of greatest value to us. The diversity of
species is an indicator of health in an ecosystem.
Ecosystems and Energy Flow
February 24, 2010
Biosphere is the living part of the environment, covers the surface and soil of Earth, all living
things underwater, and in the lower levels of the atmosphere. It can be subdivided into
ecosystems that represent the major habitats of our planet.
Ecosystems- communities of different species interacting with themselves and the abiotic (non
living) factors of a habitat.
Habitat- is the place where the populations making up the communities live. The amount of sun
light on the surface of the Earth varies from poles to equator. The maximum amount of energy
falls near the equator. Because the incoming angle, this light energy has the greatest chance of
being absorbed either as heat energy in the water or soil, or as light energy captured by the
pigment of photosynthesis. As you move away from equator, the light energy reaching the soil
declines. Some of it is reflected or refracted back into space. Because of tilt of Earth, there is a
A producer- The first stop for energy in an ecosystem. It is an organism that converts light
energy into chemical energy that will become food for another organism. Producers are
photosynthetic organisms ranging from single celled blue- green bacteria to giant red wood
Photosynthesis occurs in plants within chlorophyll and protists cells. The energy from this light
dependent reaction is used in the light independent reactions to produce raw materials for the
construction of new organic molecules.
In the light independent reactions, carbon dioxide is combined with energy, hydrogen ions and
Other compounds to produce phosphoglyceraldehyde or PGAL. PGAL is a three carbon molecule
that is central in the plant metabolism. Two PGAL can form one molecule of glucose, the fuel
molecule that stores energy. Each 3 PGAL can lose a carbon and create amino acids, and three
carbons can create fats .
The PGAL product of dark reactions allows the plants to synthesize important chemical
compounds that are needed for growth and respiration.
The energy in a ecosystem flows through a number of energy levels called trophic levels. The
trophic levels form a food chain, which is a series of organisms that eat each other and in turn
they are eaten by others. Each trophic level is basically a link in the food chain.
Food chains represent a flow of energy through feeding relationships within an ecosystem. They begin
with gross primary productivity, which is the rate at which a plant can use light energy to produce more
itself. Absorption of solar energy occurs at the first trophic level and it is accomplished by
photosynthetic organisms (producers). When the organisms in the second trophic level consume those
of the first level, this energy will then be transferred to them.
Biomass, the dry weight of all organic material contained in the organisms of a particular trophic level is
used as a way to measure primary productivity. Both biomass and energy are transferred from one level
to the next.
Not all the energy fixed and captured as ATP by the primary producers in photosynthesis is passed on
the next level of the energy pyramid. The producers and consumers carry out their own respiration and
other chemical activities, transforming the vast majority of the captured energy into unusable heat.
Net Primary Productivity is the rate at which producers store chemical energy minus the rate at which
they use chemical energy for respiration. This is what actually is left for the next trophic level. As a
general rule only about 10 % of he captured energy makes it to the next trophic level.
Primary, Secondary and Tertiary Producers
February 25, 2010
Primary consumers or herbivores, plant eaters, eat the primary producers and convert the energy and
matter stored in the bodies of the primary producers for their own uses. Only about 10% of the energy
that passes from one level is transferred to the next.
Secondary consumer usually an omnivore can eat both producers and primary consumers. It has the
advantage of being able to use energy from the first or second trophic level. Carnivores, or meat eaters
are dependent on eating herbivores, t hey only get 10% of the energy from them.
Each step of the food chain shows that there is less and less energy available to support organisms. The
loss of energy provokes that the amount of biomass at each trophic level must be lower and lower. The
top carnivores in an ecosystem are limited to a few individuals.
Tertiary consumers- feed on secondary consumers, most food chains are limited to the number of levels
that they have. In Antarctic, only 3 levels are typical, in the equator, twice as many.
The number pyramid, represented by each level, shows that there must be a very large biomass of
producers organisms to support large number of primary consumers. Fewer consumers mean that
fewer consumers can be supported. Another important implication in today’s population explosion is
that where an organism feeds on the trophic pyramid can make the difference. .
The worms, insect larvae, fungi and bacteria that help decompose and decay dead organisms represent
the last step in the use of high energy materials. They use the energy for freeing and breaking down
more complex chemicals into smaller molecules. The products of the decomposer’s work are the
elements and compounds that are recycled into materials that will make up the bodies of the next
In nature, feeding relationships are not always simple and linear. Food chains become interconnected
when organisms of one trophic level feed on organisms in one or more trophic levels in other food
chains. The results is a complex network of interconnected food chains called a food web. The energy
flow through a food web is also one way, with the lowest trophic levels having the most energy, and the
highests levels having the least.
Major Ecosystems and Genetics
February 25, 2010
1.A red coated bull and a white cow mere mated. If hair color in cattle is inherited by incomplete
dominance, what would you expect the hair color of the calf to be?
2.Explain Mendel’s law of dominance
3.what is the danger in cutting wide areas of rain forest? What is the economic importance?
4.Compare the biomass and numbers of organisms at the top and bottom of the food chain. Explain
why they are different.
5.Describe what would happen if there is no decomposers in an ecosystem
March 1, 2010
Biomes are ecosystems with similar kinds of communities sharing the same physical environment.
There are aquatic and terrestrial biomes.
Aquatic Biomes means water biomes, and there are divided in two types: marine and freshwater
Marine Biomes- They are the largest, covering about 70% of planet. They are divided in vertical zones
that share similar physical conditions. The intertidal or littoral zone is the shallowest. Physical conditions
such as waves, current tides, and bottom substrate play important roles in determining types of
organisms that can live here. Light and oxygen are found in abundance and the water temperature may
Neritic Zone- covering the shallow continental shelf is the second major zone. Light can usually
penetrate to the bottom, and many of the conditions that influence the intertidal zone play a role in
here. The major producers are phytoplankton, also it could be algae attached to it.
Epipelagic Zone- or the open ocean surface layer, is subjected to winds, waves and strong currents. High
levels of light and oxygen make it the location of most of the productivity of the planet. This zone is
called photic zone. The mesopelagic zone of the ocean, or midocean or twilight zone, it is where light
levels drop to complete darkness. There is an abundant of consumer organisms in this and deeper
zones, but there are ecosystems without producers, there is no light to produce food.
The bathypelagic and abyssopelagic zones are the deepest of the ocean. These zones and the
mesopelagic zones are dependent on food falling from surface layers, only consumers and decomposers
In 1970’s a new ecosystem was found on the mid ocean ridges. It is called the deep sea thermal vent
community. The energy sources for this ecosystem are the chemicals coming out of the bottom.
Chemosynthetic bacteria, which use chemical energy instead of sunlight, are the producers for this food
Fresh water biomass- depend upon plants living around the edges as a source of food and shelter.
Phytoplankton, which are drifting, aquatic plants may also be important producers. Seasonal
differences produce layers in these habitats.
Terrestrial Biomes are land biomes. They are limited by the amount of sunlight and the amount of
rainfall available to them. These abiotic or nonlivign factors usually show distribution by latitude and
The tundra, northernmost biomes, surround the arctic circle. The short three month summer growing
season of the tundra is compressed into the long 18 to 24 hour days. During the winter there may be
little or no light. The soil is the permafrost, ground that it never thaws. Even there is water in the form
of ice, it is not directly available to plants. Organisms adapted to tundra have a very short growing
season, lack of water. They are cold and drought resistant and grow very slowly. A few small animals,
such as caribou, live in this biome, only dwarf trees grow in here.
Taiga- The main vegetation is coniferous forest. It stretches across northern Europe, Asia and Canada.
The main physical difference between taiga and tundra is that there is more water available in the taiga.
Although there may be permafrost in the most northern part, the soil in the taiga is sandy, nutrient
poor, acidic and covered with conifer leaf litter. The long cold winters, the milder summers and the
shelter the trees provide favor more and larger animals, such as caribou and raindeer.
Desert Biomes- are found where rainfall is very limited. Plants are adapted to find and store water.
Most desert animals are small and avoid the hottest part of the day or are nocturnal. Temperature
ranges are very extreme due to lack of water, cloud cover and foliage.
Grasslands- Rainfall is limited between 25 cm and 75 cm a year. The soil is rich in humus and well
drained. This makes it ideal for crops, in other parts of the world are called savannas , pampas , steppes
and prairies. There are large grazing animals as well as small animals, as rodents, that support the
Temperatures and Deciduous Forests- there are mixture of shrubs, broad leaves, hardwood trees and
softwood trees. These middle latitude forests, once covered most of America and Europe. Four distinct
seasons are characteristic of these areas. The rain fall is 75 to 150 cm a year, and trees lose their leaves
during winter. There are great diversity of animals, bears , wolves… and animals that migrate during
The tropical rainforest-receive between 200-600 cm of rain fall a year. They are located between the
tropic of cancer and capricorn. This biome has the greatest species diversity. There is a vertical zonation
or division of this biome according to height above ground. The highest layer, the top of the trees can
be 45 m high , the main canopy from 25 to 35 m. This biome has the greatest species diversity. The
understory is below the canopy and is made by small trees and immature trees that do not require
much light. The next layer is the shrub layer which is above 10 m above the ground. The ground is
covered with leaf litter and little live plant material. Animals that live here mostly eat fruits and seeds
This biome receives the greatest amount of energy from the sun. Plants do not lose leaves, and most
nutrients are found in living plants and animals. Light competition is normal among species.
The genetic diversity of the rain forest has been threatened by its exploitation. As the rain forest are
slashed and burned to create more farm land and lumber, many species are extinct. Many of this
species have the potential of cure illness like cancer or AIDS.
Often is hard to predict what ight happen in an ecosystem if humans interfere. Since matter and energy
flow in ecosystems are interconnected any change will affect a system. For example, killing a mosquite
may cause a plant not to reproduece because mosquito pollinate the plant.
Human population affects our environment, there are almost 6.4 billion people in our world, with some
many people, were are experimenting crisis, we are depleting our environment from natural resources
like drinking water.
Nonrenewable resources are irreplaceable. One they are gone, they are gone forever. As the human
population has grown, land has been exploited for homes, industries, highways…. Scientists are
concerned with exctinctions in our ecosystems.
March 2, 2010
Population are groups of same kind of organism living together in the same area competing for the
same resources. Populations, like the organisms that make them up, are constantly changing. These
changes are response to changes in the environment.
Population size-is the number of individuals living in the same area. The size of the population is directly
related to the diversity of its gen pool. Small populations can die out if they do not have enough pool.
Large populations with more diversity, and larger gene pool have major chances of survival.
Population density- is the number of individuals in a certain area at the same time. Plants may have
densities of thousands per acre or only 4 or 5 per acre. Density has advantages and disadvantages, for
example If a disease shows up in a population it will be easier spread, but it can be an advantage against
The age structure- is the proportion of individuals in each age group. It affects the reproduction of the
There are four factors that affect populations: birth rate, death rate, immigration and emigration.
To establish the population size, we can follow an equation:
Population change= (birth rate + immigration)- (death rate + emigration)
Theoretically, a population can grow at an exponential rate indefinitely. This means that the population
is unlimited under unlimited resources. Exponential growth produces the growth curve. Bacteria under
laboratory conditions approach this potential. In nature there are many limiting factors, both abiotic
and biotic, to prevent such high growth rates, and what we call environmental resistance.
Environmental resistance helps to determine the carrying capacity. The carrying capacity is the number
of individuals of a given species that can be sustain indefinitely in an area. Most populations start slowly
and then gradually slow until it reaches their limit. Population growth then gradually slows until it
reaches a final leveling off the population numbers. The organism’s population has reached its carrying
capacity and will remain constant until environmental resistance changes. The growth curve of these
organisms is referred to as an Shaped curve or logistic growth curve. Some organisms, when
reproducing, often overshoot the carrying capacity and then decline back to new capacity.
R strategists are organisms that after overshooting their capacity decline back to new capacity.
Bacteria, algae, rodents and other opportunistis are examples of r-trategists. R- strategists try to rapidly
exploit favorable conditions, then crash, when they run out of food, or the crush because water material
build up to toxic levels and then most population dies.
K- strategists are organisms that produce a few large offspring that have a long growth and
development period. Their population follow the S curve. They live in stable environment. Most
endagered species follow this strategy.
Many organisms fall somewhere between r-strategists and k-strategists. Populations size is determined
by biotic and abiotic factors. Some factors like food or age group structure favor population growth;
others like food competition or carrying capacity limits work to decrease population growth.
One of the strongest pressure for change in population is the pressure from environment. During the
1960”s fishing was a major industry in South Florida. By the end of the decade, many tropical species
started to show up, the only walking fish that could survive where the albinos which could camouflage in
the sand. Now they are in fish farms. .The removal of any dark colored individuals from the breeding
stock ensures that the offsprings are albinos. This selection is biotic.
Not all selections are biotic. Many abiotic factors play important roles in maintaining ecosystems. Many
grasslands need periodic burning to maintain their grasslands. The Florida Everglades is a grasslands, if
there not controlling grass burning, then the grassland may be destroy by lightning. Controlled burns
are fires that are set at the right time, at the right place, and over small areas. They are used to manage
grasslands without causing the negative effects of uncontrolled fires.
March 3, 2010
Earth reuses many elements and compounds over and over by recycling matter back and forth between
nonliving and living parts in biogeochemical cycles. This matter recycling ensures that these substances
will remain in supply for both present and future living things. It allows atoms that were once part of
animals in Earth’s prehistoric past to be present in animals living today.
The water cycle is the simplest of all biochemical cycles because water does not change its chemical
composition. Water is evaporated from oceans, lakes … due to warming from sunlight. As this water
evaporates it carries heat energy with it. Water evaporated from the leaves of plants, it is called
transpiration, cool the plants as it changes from liquid state to vapor. It is the physical change from ice
to liquid to gas which moves energy through the water cycle.
As the water vapor rises, expands and cools forming clouds, the heat from condensation (vapor
changing to liquid) of the water vapor is released, heating the atmosphere, the water droplets in clouds
are often moved by wind, or translocated to another area away from site of evaporation. Eventually the
water is returned to the ground, lake, river or sea in form of precipitation, usually as rain. Rainwater
may percolate through the soil and rock forming groundwater. In other cases, water may not soak to
the ground and reach streams or ponds. These are sources of water that benefit animals, when the
water evaporates or transpires, the cycle starts again.
The water cycle helps move heat energy toward the upper atmosphere where it will radiate into space.
As in other cycles, the energy passes through the system and is diluted or spread out and changed from
kinetic energy into lower radian energy. Matter is recycled.
Carbon is found in all living organisms. It forms all chemical frameworks or skeletons for carbohydrates,
proteins, fats, nucleic acid and other organic molecules.Autotrophic organisms produce their own food,
such as green plants through photosynthesis. Heterotrophic organisms will consume energy from other
sources, breaking down these energy compounds and forming carbon dioxide gas. When both types of
organisms die, bacteria act as a decomposer and release the carbon back into the soil.
Not all organisms decay, the remain as fossil fuels. The excessive amount of carbon dioxide released in
the atmosphere for the consume of these fossil fuels have produced an increase the carbon dioxide in
the atmosphere producing climatic changes in the northern hemisphere.
The carbon cycle is linked to the movement of the energy available to living organisms. Photosynthesis
stores biological energy in the form of high chemical energy bonds. When the food materials are eaten
and broken down into simpler molecules, the new molecules are combined with oxygen to release the
stored chemical energy.
Primary productivity is limited to abiotic factors such as limited carbon dioxide. When the food
materials are eaten and broken down into simpler molecules, the new molecules are combined with
oxygen (oxidized) to release stored chemical energy. The primary productivity is limited by abiotic
factors, such the amount of carbon dioxide, or sunlight available. The other half of the carbon cycle is
made by respiration. The carbon glucose molecule release chemical energy and it is transformed to
other types of energy. The carbon is returned to the cycle as carbon and the hydrogen ions from sugar
are combined to produce water. This regenerates the raw materials needed for photosynthesis,
completing the cycle for nitrogen, carbon, hydrogen and oxygen
Most of nitrogen on Earth is found in the atmosphere as gas. This nitrogen needs to be converted into
other forms before it can be use by plants. Lighting and burning fossil fuels and biofuels create many of
the nitrogen oxides that are used in plants.
Soil bacteria and legumes (beans) can fix atmospheric nitrogen into forms that can be taken by the soil.
This process is called nitrogen fixation. Another source of nitrogen is from synthetic fertilizer made
from natural gas and atmospheric nitrogen applied to the soil.
Plants absorb the soluble nitrogen in the form of nitrates and nitrites that are the sources of nitrogen
used by plants in the synthesis of amino acids. Amino acids form proteins, animals consume these
plants proteins and digest them back to the level of amino acids. The amino acids that were originally
made by the plants are incorporated into animal proteins. When animals and plants are not eaten, then
the bacteria digest their bodies back into the soil nutrients or the atmospheric elements from which
they came. This step completes the cycle by returning the nitrogen to original source. Nitrogen animal
wastes, such as urine, return urea to the soil where bacteria decompose and convert plant nutrients,
Oxygen is involved in the cycling of carbon and nitrogen through environment. In the nitrogen and
carbon cycle, the atmosphere is the storage site; producer organisms use the sunlight energy.
Phosphorus is another essential plant nutrient and material used in energy storage compounds. In land
ecosystems, phosphorus is rapidly recycled. Phosphorus is absorbed by plants, and these plants are
eaten by animals. When the plants and animals die, they are rapidly recycled into the soil.
Phosphorus can also be washed into the ocean and converted into insoluble forms like limestone rock,