|Earth Science||Life Science||Physical Science|
1. About this Evaluation Report 2. Content Analysis 3. Instructional Analysis
|[Explanation] This section examines whether the curriculum material's content aligns with the specific key ideas that have been selected for use in the analysis.|
|[Explanation] This section examines whether the curriculum material develops an evidence-based argument in support of the key ideas, including whether the case presented is valid, comprehensible, and convincing.|
|[Explanation] This section examines whether the curriculum material makes connections (1) among the key ideas, (2) between the key ideas and their prerequisites, and (3) between the key ideas and other, related ideas.|
|[Explanation] This section notes whether the curriculum material presents any information that is more advanced than the set of key ideas, looking particularly at whether the “beyond literacy” information interrupts the presentation of the grade-appropriate information.|
|[Explanation] This section notes whether the curriculum material presents any information that contains errors, misleading statements, or statements that may reinforce commonly held student misconceptions.|
Water particles can actually be divided into even smaller units. The pieces of matter that result from dividing a water particle are no longer water. They are examples of the most basic units of matter called atoms. Atoms can’t be broken down into smaller pieces by any common methods of separating matter. Atoms are the building blocks of the universe…. [p. 157s]
On the following page, the idea is stated as one of four concepts in Dalton’s theory: “All matter is composed of tiny, indivisible particles called atoms” (p. 158s). In chapter 9, before learning about heat energy and temperature at the molecular level, students are reminded that “all matter is made up of molecules that are in constant motion” (p. 209s).
In chapter 6 and at the beginning of chapter 7, the term “particles” is used to refer to a substance’s molecules. For example, the Student Edition states:
A glass of water, for example, has many water particles, each too small to see…. Water particles can actually be divided into even smaller units. The pieces of matter that result from dividing a water particle are no longer water. They are examples of the most basic units of matter called atoms. [p. 157s]
However, on the following page, the term “particles” is used to refer to atoms: “All matter is composed of tiny, indivisible particles called atoms” (p. 158s). After a molecule is defined as a single particle of a substance (such as water) made up of two or more atoms (chapter 7, p. 170s), the term “molecule” is used to describe ideas related to the kinetic molecular theory. In Science Insights: Exploring Matter and Energy, the atomic theory is not contrasted to naive theories (such as matter being continuous or just including particles), as the statement of the key idea does.
b: These particles are extremely small—far too small
to see directly through a microscope.
c: Atoms and molecules are perpetually in motion.
Recall that all matter is made up of molecules
that are in constant motion. The gas molecules that make
up air move freely all around you. Molecules of water move
about in a container. The molecules in your chair constantly
move back and forth, or vibrate. [p. 209s]
d: Increased temperature means greater molecular motion,
so most substances expand when heated. In chapter 9, “temperature” is defined as “[t]he
measurement of the average kinetic energy of the
molecules in a substance” (p. 209s). However, kinetic
energy is not related to thermal expansion. In the explanations
given of heat transfer, thermal expansion, and changes of
state, the simpler idea that increased temperature means
greater motion is used.
In chapter 9, “temperature” is defined as “[t]he measurement of the average kinetic energy of the molecules in a substance” (p. 209s). However, kinetic energy is not related to thermal expansion. In the explanations given of heat transfer, thermal expansion, and changes of state, the simpler idea that increased temperature means greater motion is used.
e: There are differences in the arrangement and motion
of atoms and molecules in solids, liquids, and gases.
In solids, particles (1) are packed closely, (2) are (often)
arranged regularly, (3) vibrate in all directions, (4)
attract and “stick to” one another. In liquids,
particles (1) are packed closely, (2) are not arranged
regularly, (3) can slide past one another, (4) attract
and are connected loosely to one another. In gases, particles
(1) are far apart, (2) are arranged randomly, (3) spread
evenly through the spaces they occupy, (4) move in all
directions, (5) are free of one another, except during
f: Changes of state—melting, freezing, evaporating,
condensing—can be explained in terms of changes in
the arrangement, interaction, and motion of atoms and molecules.
Like every chapter in Science Insights: Exploring Matter and Energy, the chapters that are related closely to the kinetic molecular theory include numerous features (e.g., Themes in Science, Integrating the Sciences, STS Connection) that are intended to integrate the sciences, connect science to other disciplines, and integrate science, technology, and society (p. T–35). However, the connections to be made do not contribute to students’ understanding of the key physical science ideas. For example, some features simply emphasize labeling various phenomena as physical changes (e.g., pp. 147t, 148t).
In other cases, the connection that the material tries to make is contrived and relates only tangentially to the content of the section. For example, in a section on the properties of gases and their explanation at the molecular level, the text states in Integrating the Sciences that during photosynthesis, plants release oxygen [a gas] into the air and suggests that students see bubbles of oxygen forming on plant leaves in an aquarium (p. 142s).
The evaluation teams’ collective findings, presented below, should be taken as having general applicability to all of the evaluated materials, not complete and specific applicability in toto to any one of them.
Identified errors occur most frequently in drawings and other diagrams. They take the form of representations that are likely to either give rise to or reinforce misconceptions commonly held by students. Following are physical science examples of the kinds of misleading illustrative materials of most concern to the evaluation teams:
- Diagrams and drawings that show atoms or molecules of solids, liquids, and gases in colored backgrounds (for example, water molecules inside blue drop shapes) and that thereby can initiate or reinforce the misconception that particles are contained in solids, liquids, and gases, in contrast to the correct idea that substances consist of particles (with empty space between particles). This misconception may be further reinforced by the wording of diagram labels, such as “solid particles in solid water and water particles in liquid water” (emphasis added). Similarly, statements such as “explanations for what is inside things” may imply that matter contains particles (as well as other things), rather than that matter is made of particles.
- Diagrams of solids (and occasionally liquids) that do not depict the motion of atoms or molecules can give rise to, or reinforce, the misconception that atoms or molecules of solids (or liquids) are still.
- Diagrams that show molecules of liquids much farther apart than the molecules of solids are misleading; in most liquids, molecules are only a little farther apart.
- Diagrams that show particles of a substance in the solid, liquid, and gaseous state in different colors can reinforce the erroneous idea that the particles themselves are different, not their arrangement and motion. Similarly, diagrams that show particles of a substance changing size as the substance changes state can give rise to the misconception that the molecules themselves change size, becoming larger when heated.
The use of imprecise of inaccurate language is problematic in text materials, not solely in illustrations. Specifically, language that does not maintain a clear distinction between substances and atoms or molecules can mislead students to attribute macroscopic properties or behavior (such as hardness, color or physical state) to individual atoms or molecules. For example, statements such as “the particles of perfume are moving farther apart as they change into a gas and diffuse throughout the air,” “write a story from the point of view of a particle in the solid phase as it melts and then evaporates,” and “draw what happens when the particles change state” (emphasis added) imply inaccurately that the particles themselves change state (melt, evaporate, etc.).