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Big Idea - Juneau School Distric

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					                                                                          Big Idea – All matter is made up of atoms and molecules of a finite
7thGrade Physical Science                                                 number of elements, arranged in ways that determine its possibilities.
   Structure of Matter
                                                                          Essential Question
                                                                               How does the structure of matter affect its properties and
                                                                              interactions?
Teacher Background Information
Science Matters, Chapters 4 and 6
Science for All Americans, Chapter 4, p 46-49                              AAAS Benchmarks/National and Science Education
Benchmarks for Science Literacy, Pages 75-90                              Standards
National Science Education Standards, Page 149, 154                   Structure of Matter: Atoms and Molecules
We need current internet sources listed here                            Over 100 different elements have been identified, out of which everything is
                                                                      made. 4D/M5
                                                                        All matter is made up of atoms, which are far too small to see directly
                                                                      through a microscope. 4D/M1a
                                                                        There are groups of elements that have similar properties, including highly
                                                                      reactive metals, less-reactive metals, highly reactive nonmetals and some
Instructional Implications                                            almost completely nonreactive gases 4D/M6a
In grades 5–8, the focus shifts from properties of objects and          The atoms of any element are like other atoms of the same element, but are
materials to the characteristic properties of the substances from     different from the atoms of other elements. 4D/M1b
which the materials are made. Students observe and measure              Atoms may link together in well-defined molecules, or may be packed
                                                                      together in crystal patterns. Different arrangements of atoms into groups
characteristic properties, such as boiling points, melting points,    compose all substances and determine the characteristic properties of
solubility, and simple chemical changes of pure substances and        substances. 4D/M1cd
use those properties to distinguish and separate one substance         Chemical elements do not break down during normal laboratory reactions
from another. (NSES)                                                  involving such treatments as heating, exposure to electric current, or reaction
    Elements and compounds can be defined operationally from          with acids. (NSES)
their chemical characteristics. Most important, students should       Structure of Matter: Conservation of Matter
see a great many examples of reactions between substances that           Equal volumes of different materials usually have different masses. 4D/M2
produce new substances very different from the reactants. Then          No matter how substances within a closed system interact with one
they can be helped to see that the value of the notion of atoms       another, or how they combine or break apart, the total mass of the system
                                                                      remains the            same. 4D/M7a
lies in the explanations it provides for a wide variety of behavior     The idea of atoms explains the conservation of matter: If the number of
of matter.                                                            atoms stays the same no matter how the same atoms are rearranged, then
    Going into details of the structure of the atom is unnecessary    their total mass stays the same. 4D/M7b
at this level. By the end of the 8th grade, students should have      Structure of Matter: States of Matter
sufficient grasp of the general idea that a wide variety of              Most substances can exist as a solid, liquid, or gas, depending on
phenomena can be explained by alternative arrangements of             temperature.
vast numbers of invisibly tiny, moving parts. Possible                  Energy appears in different forms. Heat energy is in the disorderly motion
differences in atoms of the same element should be avoided at         of          molecules;. 4E/M4*
this stage.                                                             Atoms and molecules are perpetually in motion. Increased temperature
                                                                      means greater average energy of motion, so most substances expand when
   Students should become familiar with characteristics of            heated.* 4D/M3
different states of matter and transitions between them. The
                                                                        In solids, the atoms are closely locked in position and can only vibrate. In
behavior of gases—such as their compressibility and their             liquids, the atoms or molecules have higher energy, are more loosely
expansion with temperature—may be investigated for                    connected, and can slide past one another; some molecules may get enough
qualitative explanation.                                              energy to escape into a gas. In gases, the atoms or molecules have still more
   When students first begin to understand atoms, they cannot         energy and are free of one another except during occasional collisions.
confidently make the distinction between atoms and molecules          4D/M3
or make distinctions that depend upon it—among elements,              Structure of Matter: Chemical Reactions
mixtures, and compounds, or between "chemical" and "physical"          A substance has characteristic properties, such as density, a boiling point,
changes. An understanding of how things happen on the atomic          and solubility, all of which are independent of the amount of the sample. A
level—making and breaking bonds—is more important than                mixture of substances often can be separated into the original substances
                                                                      using one or more of the characteristic properties. (NSES)
memorizing the official definitions.                                   When substances interact to form new substances, the elements composing
                                                                      them combine in new ways. In such recombinations, the properties of the
                                                                      new combinations may be very different from those of the old. (SFAA page. 4)
                                                                       The temperature and acidity of a solution influence reaction rates. Many
                                                                      substances dissolve in water, which may greatly facilitate reactions between
                                                                      them. 4D/M4
Student Difficulties and Misconceptions                                Energy appears in different forms. Chemical energy is in the arrangement of
 Students usually bring some vocabulary and primitive                 atoms; 4E/M4
notions of atomicity to the science class but often lack              Energy Transformation
understanding of the evidence and the logical arguments that           Energy appears in different forms and can be transformed within a system.
support the particulate model of matter. Their early ideas are        Chemical energy is associated with the composition of a substance. 4E/M4
that the particles have the same properties as the parent
material; that is, they are a tiny piece of the substance.
 Students are often confused by the difference between heat
and temperature.
                                               Alaska GLE’s
Local Connections
                                               The student demonstrates understanding of the structure
States of matter: snow, ice, glacier,          and properties of matter by
                                               [6] SB1.1 using models to represent matter as it changes from
  streamflow studies                           one state to another
                                               [7] SB1.1 using physical properties (i.e., density, boiling point,
Sewage treatment?                              freezing point, conductivity) to differentiate among and/or
Brewery                                        separate materials (i.e., elements, compounds, and mixtures)
                                               [8] SB1.1 using physical and chemical properties (i.e., density,
                                               boiling point, freezing point, conductivity, flammability) to
                                               differentiate among materials (i.e., elements, compounds, and
                                               mixtures)
                                               The student demonstrates an understanding of the
                                               interactions between matter and energy and the effects of
                                               these interactions on systems by
                                               [6] SB3.1 recognizing that most substances can exit as a solid,
Materials/Resources                            liquid, or gas depending on temperature
                                               [7] SB3.1 recognizing that most substances can exist as a solid,
                                               liquid, or gas depending on the motion of their particles
Physical properties of matter STC Kit          [8] SB3.1 exploring changes of state with increase or decrease
                                               of particles speed associated with heat transfer (L)
                                               [8] SB3.2 exploring through a variety of models (e.g.,
                                               gumdrops and toothpicks) how atoms may bond together
                                               into well defined molecules or bond together in large
                                               arrays (L)




Assessments
Science Probes Volume 1:
Science Probe #5 - Ice Cubes in a Bag          Grade Level Scientists
Science Probe #6 - Lemonade
Science Probe #7 - Cookie Crumbles
                                                 Antoine Lavoisier
Science Probe #8 - Seedlings in a Jar
Science Probe #9 - Is it Melting
Science Probe #10 - Is it Matter?
Science Probe #11 - Is it Made of Molecules?
Science Probe #12 - The Rusty Nails
Science Probe #18- Is it made of Cells?        Connections to Other Topics:
Science Probe #21 - Wet Jeans
                                               Gas laws to weather
Science Notebooks                              States of matter to water cycle
                                               Elements to rock cycle
                                               Acid/base distinctions to ecology
                                               Reactions to cells in human body

				
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