# EDUC Designing Learning with Technology by MikeJenny

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```									       CIPS Institute for Middle School
Science Teachers

Constructing Ideas in Physical Science

Joan Abdallah , AAAS
Darcy Hampton, DCPS
Davina Pruitt-Mentle, University of Maryland
Session 8 Debriefing

• What do you remember from yesterday‟s
session (no peeking at text or notes)
• What were the “essential questions” being
• What conclusions did “we” decide

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Deeper Questions

• What deeper questions could you
• What misconceptions or
misinterpretations can you foresee?
• How or what would you say?

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Deeper Questions or Possible
Misinterpretations

“What makes light”?
“What makes energy”?
“What makes different
colors”?

What would you say?

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Electromagnetic Spectrum

How Roy G. BV Lost a Vowel
This was originally "ROY G. BIV", because it used to be common to call the region between blue
and violet "indigo". In modern usage, indigo is not usually distinguished as a separate color in the
visible spectrum; thus Roy no longer has any vowels in his last name.
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See Handout:
Continuous and Line Spectra

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So….
 Things are made up of atoms
 Atoms
 Protons
 Electrons
 Electrons do a lot of spinning and hopping around
(that‟s what causes things to have certain shapes
and textures)
 When electrons get excited, they jump from lower
ground state to excited state and then back to rest
again
 This jumping back and forth = radiant energy

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How Do you Measure Radiant Energy?

• In order to understand behavior of e-, you need to know their:
– Velocity
– Location
• Werner Heisenberg (highs-en-berg), German, showed that it is
impossible to know both the exact position and the exact
momentum of an object (e-) at the same time (Heisenberg’s
Uncertainity Principle)
– Can not measure where the e- is since the “nature” of measuring is
to “move” something
– To know location you would have to “measure” it –but when you
measure it would effect (change) the velocity
– Smaller something is the more uncertain the position will be after
measuring it
– (Δx) (Δmv)  h/4                     Need more coffee?
• (Δx) = change in position
• (Δmv) = momentum = mass x velocity (related to KE)
– h/4 = some constant (Planck‟s constant/4)
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The de Broglie Hypothesis
• This enabled de
• 1923, de Broglie
(French)
Broglie to predict the
• Used Planck‟s/(and
wavelength of a
Einstein) idea…that                    particle when given
radiation is made up of                mass (m) and
packets of energy (this                velocity.
gave waves properties                • General Trend
of particles)
– as mass (e-)
• He wanted to prove that
increases,  decreases
particles could have
– e- mass ↑  ↓
properties like waves

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The de Broglie Hypothesis cont.

• Using E = mc2 (Einstein) and E = h  (Planck)
• Derived: mc2 = h 
• Substituted v (general velocity) for c
• Substituted v/  for , because the frequency of a
wave is equal to its velocity/by its wavelength
• mv2 = h/
• or  = h /mv2 = h/mv

See: http://cougar.slvhs.slv.k12.ca.us/~pboomer/chemtextbook/cch9.html

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The de Broglie Hypothesis cont.
• From this, shown that e- stream acts in the same way
as a ray of light

• Given credit for indicating how to predict the
wavelength of particular electrons

• Also showed that e- have properties of both waves
and particles = wave-particle duality of nature

• This is why you can not measure the velocity &
location of e- at the same time

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Two Formulas
•  (m) X  (s-1) = c (where c =speed of light or 3.00 x 108 m/s)

• Louis de Broglie suggested that the e- in its circular path about
the nucleus has associated with it particular wavelengths, and
also that the wavelength of the e- depends on its mass and
velocity

• He called this matter waves, and used it to describe the wave
characteristics of material particles

•  = h/mv
– mv also called momentum
– h= Planck‟s constant 6.63 x 10-34 J.s (1 J = 1 kg m2/s2)

Show Subscripts and Symbols                 See handout (5.2)
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Making the Connection

• De Broglie = e- act as
• The link between
waves (properties of 
these two concepts
and  )
= h = Planck‟s
• Schrodinger = e- act                    constant
as particles --
• Wave-particle
different  (energy
duality of nature
property) &  (mass)

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Wave-particle Duality of Nature

• Shows or proves that a
beam of e- will produce                          1s _
a diffraction pattern like                       2s_
light patterns                                 2p _ _ _
• Bohr and Schodinger                 •   1 & 2 = shells
called this : wave or               •   S,p,d,f = subshells
quantum mechanics                   •   _ = orbitals
• i.e., where are we more             •   Distance between the rings =
“nodes”, places where you
likely to “find” e- at a                will not find e-
given moment in time

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Summary
• Planck‟s hypothesis stated that energy
is given off on quanta (photon)
continuously
• Bohr showed that absorption of light at
set  correspond to definite changes in
energy of the e-
• Reasoned that orbits (rings) around
nucleus must have a definite diameter
and that e- could occupy only certain
orbits
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Summary cont.

• The energy absorbed when the atom was excited =
the energy difference between orbits
• Because these orbits represent definite energy
levels, a definite amount of energy is radiated
• The size of the smallest orbit an e- can occupy (one
closest to nucleus), the ground state, can be
calculated
• Energy is determined by the movement of e- between
energy levels that are specific for each element
• The same set of energy levels will always produce
the same spectrum

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• CEA Light Tour
[Local]

See Handout

From:
http://cse.ssl.berkeley.edu/light/light_tour.html

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Other Resources
• Waves –Virtual Lab [Local]

• Exploring Earth [Local] Observe the change in a
star's spectrum as its motion changes

• Electromagnetic spectrum - Wikipedia

• Discovery-The Color Spectrum How does it work?
[Local]

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But I can not see e-, so how do we know?

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States of Matter

• Matter- has mass, occupies space
• Physical states of matter
– Solid
– Liquid
– Gas
– Plasma
One of the four states of matter. (The other three are solid, liquid and gas.) Consists of
a gas of positively charged and negatively charged particles with approximately equal
concentrations of both so that the total gas is approximately charge neutral. A plasma
can be produced from a gas if enough energy is added to cause the electrically neutral
atoms of the gas to split into positively and negatively charged atoms and electrons.
See also: The Plasma State of Matter.
www.spacescience.org/ExploringSpace/Glossary/1.html
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Kinetic Molecular Theory of Matter

Solid        Liquid                Gas
• States:                           Own definite       Indefinite            Indefinite
– All matter is in constant shape              shape                 shape
motion                    Own definite       Definite              Indefinite
– An increase in            volume             volume                volume
temperature increases Independent            Takes shape           Takes
motion and decreases of container            of container          shapes of
attraction forces holding shape              (until it fills it)   container
the matter together                                                and fills it
– SLGP

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Physical vs. Chemical Properties

Physical Properties                    Chemical Properties
• Can be observed without                     • Undergoes changes in
changing form                                 chemical composition
–     Color
– Flammability or not
–     Odor
flammable
–     Taste
–     Size                               – Reacts/failure to react
–     BPo                                  with another
–     MPo                                – Decomposes
–     Density                            – Rusting
–     Specific heat (Cp)
– Combustion
–     Hardness
–     Solubility
–     Mass
–     Temperature
–     Heat capacity
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Properties can also be classified as:

Intensive                             Extensive
• Values do not                       • Depend on sample
depend on size of                     size
portion                               – Mass
–    Temperature                – Volume
–    MPo                        – Length
–    BPo
–    FPo

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Properties
• Molecules vibrate faster when they are
stirred-therefore, this helps them dissolve
faster
• When heated dissolves faster
• At certain temperature (w/ a solid) when heat
added, the heat breaks the bonds. Solid
matter changes to liquid (Melting Point MPo)
• With a solid when freezes, attractive forces
cause molecules to lock together into solid
state (Freezing Point FPo)

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Liquid Changes

•     Change of liquid into vapor  evaporation
•     Change of vapor into a liquid  condensation
•     Opposite of condensation  evaporation
•     Opposite of evaporation  condensation

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Changes cont.
• As temperature falls, and the gaseous molecules slow down,
their weak attractive forces get an opportunity to bind the
molecules together and change the gas (vapor) into a liquid.
When water vapor touches cool dust particles in the air,
condensation takes place. The droplets of water, suspended in
the air, form clouds and rain
– Gas  Condensation  Liquid
• The changing of a solid into a gas without becoming liquid 
sublimation. A lot of heat is added to the solid. This added heat
causes the molecular vibrations to become so violent that the
molecules of the solid completely break away from each other
and enter into a gaseous state
– Solid  Sublimation  Gas
•       Ex. Mothballs, vaporization (nuclear fallout)

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Changes cont.
• We know that water vapor will condense on a cool
speck of dust. If the water vapor touches a very cold
speck of dust in the air, the gaseous water may
crystallize without condensing first. The ice crystals,
suspended in the air, form clouds. If conditions are
right, these crystals may fall to the ground as snow.
– The changing of a gas into a solid = sublimation
• By definition, sublimation can indicate going from gas
to solid or from solid to gas…although in “chemistry”
usually implies going from the solid state to a gas
state.

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Putting It All Together

GAS

SOLID           Melts                LIQUID
Freezes

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Property Changes
Physical Change                         Chemical Change
• No new substance is                   • Involves a change in
ever formed                             basic nature (chemical
composition)
– Tearing paper
• Change in at least one
– Sulfur & iron
new substance
– Sharpening
– Sulfur & iron heated
– Bite
– Burning paper
– Chew
– Digesting
– Breaking glass
– Sour milk
– Detonation

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Quiz
•     Rust                     •   C
•     Melts                    •   P
•     Sharpening               •   P
•     Digesting                •   C
•     Biting                   •   P
•     Burning                  •   C
•     Slicing                  •   P
•     Detonation               •   C
•     Souring                  •   C
•     Breaking                 •   P

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Break?

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CIPS

• Unit 4
– Cycle 1
– Activity 1,2 & 3

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Energy & Heat
• Physical and chemical                         Ex.
changes are always                               Object A = 25°C
accomplished by energy                           Object B = 20°C
transfer                                      What happens when they are
mixed?
• The most common form of
Energy will continue to transfer
energy transform or
until the temperature of the
change is heat                                  objects are equal.
– Heat is a form of energy that              The energy transfer as a result
flows between a system and                   of a temperature difference
its surroundings                             is called heat and is
– Heat flows from a warmer                     represented by the letter (q).
object to a cooler one

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Energy (continued)
• If energy is absorbed = endothermic reaction
• If energy is given off = exothermic reaction
– Match = exothermic
– Cold pack = endothermic
• Both forms require a certain amount of energy to get started – activation
energy
• Quantitative measurements of energy changes are expressed in joules
(J). This is a derived SI unit
–    Older unit = calorie
–    One calorie (c) = 4.184 J
–    (C) dietary unit  calorie (c)
–    The heat needed to raise 1 g of a substance by 1°C is called specific heat
(Cp) of the substance
Examples: Sand and water – different Cp values
Which gets hotter at the beach?
Which cools down faster?
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Dietary Calories
• The heat required to increase the temperature of 1g of water 1°C =
4.184J
• Dietary Calories (C) are 1000 times as large as a calorie (c)
• Caloric values are the amount of energy the human body can
obtain by chemically breaking down food
• The Law of Conservation of Energy shows that in an insulated
system, any heat loss by 1 quantity of matter must be gained by
another. The transfer of energy takes place between 2 quantities of
matter that are at different temperatures until they both reach an
equal temperature

Example: An average size backed potato (200g) has an energy value of 686,000 J. How many
calories is this?
4.184J = 1 c, 1000 c = 1 C
686000J/4.184 J = 164,000 c
164,000 c/ 1000 C=164C
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Energy Transfer

• The amount of heat energy transferred can be
calculated by:
– (heat gained) = (mass in grams)(change in T)(specific heat)
– q = (m)(T)(Cp)
– T = Tf - Ti

Example: How much heat is lost when a solid aluminum block with a mass
of 4100g cools from 660.0°C to 25°C? (Cp = 0.902 J/g°C)
q = (m)(T)(Cp)
T = 660.0°C - 25°C = 635°C

therefore: q = (4110g)(635°C)(0.902 J/g. °C) = 2,350,000 J

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Matter

Mixture                                Pure Substance
• Most Natural Samples                 • Few naturally pure gold
• Physical combination of                & diamond
2 or more substances                 • Only 1 substance
• Variable composition                 • Definite and constant
• Properties vary as                     composition
composition varies                   • Properties under a
• Can separate by                        given set of conditions
physical means

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Mixture
Heterogeneous                                Homogeneous
• Visible difference in                      • Only 1 visible phase
parts and phases                             – Homogenized milk
–    Oil and vinegar                  – Air (pure)
–    Cookie                           – Metal Alloy (14K
–    Pizza                              gold)
–    Dirt                             – Sugar and Water
–    Marble                           – Gasoline
–    Raw Milk

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Pure Substance
Compound
Element
aspirin, H2O, CO2
Au, Ag, Cu, H+
• Can be broken down into 2 or
• Pure and cannot be divided into
more simpler substances by
simpler substances by physical
chemical means
or chemical means
• Over six million known chemical
• 90 naturally occurring
combinations of 2 or more
elements                           • 22 synthetic
• 7000 more discovered per week
with chemical abstracts service
• Definite-constant element                           Element
composition            Simpler Compound
Compound
Element
Element
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Matter

Heterogeneous materials               Homogeneous materials

Solutions              Pure substances

Mixtures                Compounds              Elements
CIPS

Unit 5

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Subatomic Particles
Building Blocks of Atoms
• Proton: (+)                                                • Electron: (-)
– 1.673 x 10-28 g                                         – Outside „e‟ cloud
– Discovered by Goldstein                                 – 9.109 x 10-28 g (1/1839 of a
(1886)                                                    proton)
– Inside the nucleus                                      – Discovered by Joseph John
(credit given to Rutherford – beam of alpha particles             Thomson (1897)
on thin metal foil experiment. Explained nucleus
in core, made up of neutrons and protons)                       • It‟s charge to mass ration
(e/m) = 1.758819 x 108 c/g
• Neutron: (no charge)
– c = charge of electron in
– 1.675 x      g       10-24                                Coulombs
– Discovered by James                                     – Millikan determined mass
– Inside nucleus

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Atoms

•    Atom – smallest particle of an element that can exist and still hold properties
•    “Atomos” – Greek – uncut/indivisible. Democritus proposed that elements are
composed of tiny particles
•    John Dalton (1808) published The Atomic Theory of Matter
1.      All matter is made of atoms
2.      All atoms of a given type are similar to one another and different from all other types
3.      The relative number and arrangement of different types of atoms contained in a pure
substance determines its identity (Law of Multiple Proportions)
4.      Chemical change = a union, separation , or rearrangement of atoms to give a new
substance
5.      Only whole atoms can participate in or result from any chemical change, since atoms
are considered indestructible during such changes (Law of Conservation of Mass)
•    Antonine Lavoier demonstrated via careful measurements that when combustion
is carried out in a closed container – the mass of the products = the mass of the
reactants

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Formula Mass
H=1                            Billy = 150
O = 16                         Susie = 100
H 2O                           Billy4Susie = 800
2x1=2
1 x 16 = 16
Total = 18 

H2SO4                            2CaCl2
H = 2x1 = 2                      Ca = 2x40 = 80
S = 1 x 32 = 32                  S = 4 x 36 = 144
O = 4 x 16 = 64               Total 224
Total 98

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Abundance of Elements in
Matter
Universe                  Atmosphere     Earth’s Crust
• H 75-91%                • N2 78.3%     • O2 60%
• He 9%                   • O2 21%       • Si 20%
• Al 6%
Earth                     Human Body     • H2 3%
• O2 49.3%                • H2 63%       • Ca 2.5%
• Fe 16.5%                • O2 25.5%     • Mg 2.4%
• Si 14.5%                • C 9.5%       • Fe 2.2%
• Mg 14.2%                • N2 1.4%      • Na 2.1%

AAAS/DCPS CIPS Workshop         8/2-8/13                   45
Element Names – based on
• Geographical
Names                              • Gods
– Germanium                      – He (helios – sun‟s
(German)                         corona)
– Francium (France)          • Properties (color)
– Polonium (Poland)              – Chlorine - chloros –
• Planets                                  greenish/yellow
–    Mercury                     – Iridium –iris – various
colors
–    Uranium
–    Neptunium
–    Plutonium
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Chemical Symbols
• 1814 – Swedish – Jons Jakob Berzelius
– Symbols = shorthand for name
• N = nitrogen
• Ca = Calcium                     – Latin
Iron       Fe   Ferrum
– Latin or other name                        Gold       Au   Aurum
Antimony Sb     Stibium
Copper     Cu   Cuprum
Mercury    Hg
Hydrargyrum
– German
Potassium K     Kalium
Tungsten   W   Wolfram
Silver     Ag   Argentum
Sodium     Na   Natrium
Tin        Sn   Stannum
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Generic Nomenclature:
Provisional Names
• International Union of Pure and Applied Chemistry
(IUPAC)
• Latin – Greek Names
– 0 =nil, 1=un, 2=bi, 3=tri, 4=quad, 5=pent, 6=hex, 7=sept,
8=oct, 9=enn
– + ium
– i.e.
•   104 un nil quad ium   Unq
•   105 un nil pentium                Unp
•   106 un nil hex ium                Unh
•   110 un un nil ium                 Uun
– Most nave been given names anyway
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