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Middle Grades Science Textbooks: A Benchmarks-Based Evaluation

Matter and Molecules (stand-alone unit). Michigan State University, 1988.
Earth Science Life Science Physical Science

About this Evaluation Report
Content Analysis
Instructional Analysis
I. [Explanation] This category consists of criteria for determining whether the curriculum material attempts to make its purposes explicit and meaningful to students, either in the student text itself or through suggestions to the teacher. The sequence of lessons or activities is also important in accomplishing the stated purpose, since ideas often build on each other.
II. [Explanation] Fostering understanding in students requires taking time to attend to the ideas they already have, both ideas that are incorrect and ideas that can serve as a foundation for subsequent learning. This category consists of criteria for determining whether the curriculum material contains specific suggestions for identifying and addressing students’ ideas.
III. [Explanation] Much of the point of science is to explain phenomena in terms of a small number of principles or ideas. For students to appreciate this explanatory power, they need to have a sense of the range of phenomena that science can explain. The criteria in this category examine whether the curriculum material relates important scientific ideas to a range of relevant phenomena and provides either firsthand experiences with the phenomena or a vicarious sense of phenomena that are not presented firsthand.
IV. [Explanation] Science literacy requires that students understand the link between scientific ideas and the phenomena that they can explain. Furthermore, students should see the ideas as useful and become skillful at applying them. This category consists of criteria for determining whether the curriculum material expresses and develops the key ideas in ways that are accessible and intelligible to students, and that demonstrate the usefulness of the key ideas and provide practice in varied contexts.
V. [Explanation] Engaging students in experiences with phenomena (category III) and presenting them with scientific ideas (category IV) will not lead to effective learning unless students are given time, opportunities, and guidance to make sense of the experiences and ideas. This category consists of criteria for determining whether the curriculum material provides students with opportunities to express, think about, and reshape their ideas, as well as guidance on developing an understanding of what they experience.
VI. [Explanation] This category consists of criteria for evaluating whether the curriculum material includes a variety of aligned assessments that apply the key ideas taught in the material.
VII. [Explanation] The criteria in this category provide analysts with the opportunity to comment on features that enhance the use and implementation of the curriculum material by all students.

I. Providing a Sense of Purpose

Conveying unit purpose (Rating = Poor)

In the Unit Introduction, Matter and Molecules describes briefly what students will learn:
For the next several weeks you will be studying matter and molecules. You will learn to explain what matter is made of and how it changes.... As you learn about the substances in the world around you, you will discover that this unit is different from most other Science Books. You will learn some new and interesting facts, but most importantly, you will use those facts to explain things in the world around you. This unit is designed to help you explain things, not just learn facts. (Science Book, p. 1s)

In describing what students will learn, Matter and Molecules uses abstractions that students are not familiar with (such as “molecules” and “substances”). In addition, the statement: “This unit is designed to help you explain things, not just learn facts” is not likely to make sense to students who have not studied units like this before that focused on developing explanations. Hence, it is not likely that this unit purpose will be comprehensible or motivating to students. Furthermore, the text merely tells students about the purpose; it does not engage them in thinking about it. The whole unit relates to the purpose identified, which is returned to at the end of the unit:

Your long study of molecules is over. We hope you have learned a lot about molecules and about how they can help you explain many different things. Can you think back to how molecules can explain the way things dissolve? What about thermal expansion? Compression of gases? Changes of state? (Science Book, p. 69s)

Conveying lesson/activity purpose (Rating = Very Good)

Matter and Molecules routinely conveys the purpose of each activity to teachers and students in a way that would be comprehensible to students and frequently provides questions to focus students' attention on activities and to help them think about their central question before they start the activities. For example, in lesson 1.1, students engage in an activity in which they seal an ice cube in a plastic bag and try to change it into liquid water (Activity Book, activity 1.1, p. 1s). The Teacher’s Guide states that the purpose of lesson 1.1 is “To help students describe ice and liquid water as two different states of the same substance” (Science Book, p. T-15). The text that students read before activity 1.1 states:

You certainly know about liquid water. That's what you drink and take showers in. But have you seen any solid water around recently? Of course you have, only you probably called it ice.

How do you know that ice is really solid water? Can you show it? You probably can, but there isn't much time, so you'll have to hurry! (Science Book, p. 2s)

The Teacher’s Guide recommends that “students read the first two paragraphs of the student text. Elicit as many responses as possible to the question ‘How do you know that ice is really solid water?’ Discuss the student responses until students understand the problem for the activity” (Science Book, p. T-15). The text that students read before activity 1.1 asks: “How do you know that ice is really solid water? Can you show it? You probably can, but there isn't much time, so you'll have to hurry!” (Science Book, p. 2s). In introducing the activity, students are told: “You will show that ice is really solid water by changing it into liquid water, as quickly as possible” (Activity Book, p. 1s). They are encouraged to reflect on their predictions in question 2: “How does this activity show that ice and water are really the same?” (p. 1s).

The text summarizes what students have learned so far and what they need to learn or do next at appropriate points. At the beginning and the end of most lessons, there is a brief summary of what students did or learned in the previous lesson and what they will do or learn in the following lesson (e.g., see the Science Book, pp. 3–4s). In addition, at the beginning and the end of most lesson clusters, there is a brief summary of what students did or learned in the previous lesson cluster and what they will do or learn in the following lesson cluster (e.g., see the Science Book, pp. 13s, 20s).

Matter and Molecules rarely connects the purpose of individual lessons and activities to the unit purpose. An exception is the following statement at the beginning of Lesson Cluster 4:

In the lessons that you have already studied, you have been learning quite a bit about molecules; what they are, how small they are, how they move, how they are arranged, and so on. These lessons have been helping you explain things in terms of molecules, not just in terms of what you see, hear, or feel. (Science Book, p. 27s)

Justifying lesson/activity sequence (Rating = Satisfactory)

Although Matter and Molecules does not give explicitly a rationale for the sequence of its activities, they appear to be connected in a logical order. Students start with simple phenomena (e.g., the melting and solidifying of ice) and move to more complex phenomena (e.g., the water cycle). In Lesson Cluster 1, the student text explains states of water in terms of the arrangement and motion of the water molecules that compose them all; in Lesson Cluster 2, the text explains differences among various liquids and solids in terms of the arrangement and motion of the molecules that compose them all; and in Lesson Cluster 3, the text explains differences among various gases in terms of their different molecular compositions. In Lesson Clusters 4 and 5, students are asked to use the ideas presented in clusters 1 through 3 to explain different phenomena (such as compressing liquids and gases and dissolving) in terms of the motion and arrangement of molecules. In cluster 6, students are asked to use the ideas in clusters 1 through 3, together with the idea that heating or cooling makes molecules move faster or slower, to explain thermal expansion. In clusters 7 through 9, students are asked to take the ideas in clusters 1 through 3, in conjunction with the ideas that heating or cooling makes molecules move faster or slower and that molecules attract each other to explain more complex phenomena: the changes of state. Matter and Molecules points out some aspects of the sequence of activities in its notes to teachers:
In Lesson Clusters 1 and 2, students learned differences among solids, liquids, and gases of substances in terms of the arrangements and motions of their molecules. The contents in Lesson Clusters 7, 8, and 9 are about how or why a substance changes from one state to another. In Lesson Cluster 6, students have learned that heating or cooling makes molecules move faster or slower. Thus, the students need to integrate scientific ideas they have already learned in understanding and explaining various changes of state in these last three lesson clusters. The specific example used is water in its three states, and the same explanation applies to other substances. (Science Book, p. T-79)

II. Taking Account of Student Ideas

Attending to prerequisite knowledge and skills (Rating = Satisfactory)

Matter and Molecules explicitly alerts teachers to two prerequisite ideas: in order for students to describe air in terms of its molecular composition, they must be convinced first that air is a substance, and students need to understand and become familiar with non-molecular aspects of physical changes macroscopically before they can be expected to consider theories that explain them (Science Book, p. T-5). In addition to these prerequisites, Matter and Molecules addresses other prerequisites such as: “Materials can exist in different states—solid, liquid, and gas. Some common materials, such as water, can be changed from one state to another by heating and cooling” (pp. 2-4s), and “Air is a substance that surrounds us, takes up space, and whose motion we feel as wind” (p. 22s). For example, students experiment with air in a plastic bag and attempt to fill an inverted, air-filled cup with water to help them see that air takes up space and that it is matter (hence, it is made of moving molecules) (Activity Book, pp. 12–14s).

Matter and Molecules does not provide students with experiences that can help them see that collections of pieces have properties that the individual pieces do not have. Without this prerequisite knowledge, students may attribute macroscopic phenomena (such as expansion) to the properties of individual particles (the ability to expand). Students need help in moving to the scientific view that phenomena like expansion are due to changes in the arrangement and motion of a collection of particles. For example, students could observe and describe the behavior of powders, marbles, sugar cubes, or wooden blocks (which, for example, can be “poured” out of a container) and consider that the collections may have new properties that the individual pieces do not. This is not done in Matter and Molecules, nor are students asked to think about such experiences that they might have had in earlier grades.

Alerting teachers to commonly held student ideas (Rating = Excellent)

Matter and Molecules alerts the teacher to most of the relevant student difficulties and commonly held ideas that are documented in research studies and represents research findings in an accurate way. At the beginning of each lesson cluster, the Teacher’s Guide has a chart of Conceptual Contrasts that compares the scientific view with students' misconceptions of the key ideas (see the Science Book, pp. T-14, T-27, T-40, T-48, T-61, T-69, T-80, T-90, T-100), and describes common misconceptions related to the ideas to be developed in the cluster (see the Science Book, pp. T-13, T-38, T-49, T-60, T-67–69, T-79). The contrast between the students' ideas and the scientific ideas makes it likely that teachers will understand better where the problem lies in students' ideas. For example, in the Conceptual Contrasts chart for Lesson Cluster 1, the scientific idea that “All molecules are constantly moving” is contrasted with students' conceptions that “Molecules may sometimes be still, especially in solids” and “Molecules simply share in observable movements of substances (e.g., molecules do not move in ice because ice is frozen)” (Science Book, p. T-14). These student ideas are explained further on page T-13. The Teacher’s Guide also warns teachers about students' potential difficulties with the activities used to teach the key ideas. For example, when learning about liquid expansion, students put a thermometer into warm water and observe what happens to the column of colored liquid. Teachers are alerted that “Some students may think that the liquid goes up the thermometer tube when the bulb gets warmer because ‘heat rises” (Science Book, p. T-74).

Assisting teachers in identifying their students’ ideas (Rating = Satisfactory)

Matter and Molecules includes some specific questions and tasks for teachers to use to find out what their students think. In some lesson clusters, the Activity Book contains questions to elicit students' understanding of the key ideas before they are introduced. This is made clear in the Introduction to the Activity Book:
Some questions are intended primarily for the purpose of eliciting students' ideas about topics that they have not yet studied and may only partially understand. These questions should not be graded on a right-or-wrong basis; they should be used as a basis for discussion by small groups of students or by the whole class. (p. T-i)

For example, in Activity 6.1, students place hard candy into a cup of hot water and one of cold water. They are asked to predict how what happens in the two cups will be the same, how it will be different, and to explain their predictions. This is done before students encounter the idea that molecules of hot substances move faster than those of cold substances (Activity Book, p. 31s).

In addition, teachers are supplied with two-part transparencies to encourage them to find out what their students think about the key ideas. The Science Book states that:

Each of the transparencies has two layers. The bottom layer poses a question about a situation. You should encourage students to express their ideas about that situation and the answer to the question. After your students have tried to answer the question and you are aware of how they think, you can flip down the overlay to give them a scientific answer to the question. (p. T-8)

Matter and Molecules does not make it clear whether the transparencies are to be presented before or after the scientific ideas are introduced. Hence, it is not clear whether the transparencies should be used to identify students' ideas before instruction or as tools for embedded assessment. For example, in lesson 2.3, teachers are encouraged to use Transparency 4 on page T-35 to elicit students' ideas about how molecules are arranged and how they move in solid sugar, liquid alcohol, and oxygen gas (Science Book, p. T-34). It is not clear whether this transparency is to be used before or after students learn about the different arrangement and motion of molecules in solids, liquids, and gases.

The questions that are intended to help teachers find out what students think typically ask students to make predictions or to give descriptions or explanations of properties of substances or phenomena. They are posed in ways that are likely to be comprehensible to students who are not familiar with the scientific concepts and terms. However, the text does not explicitly encourage teachers to use probing questions to clarify what students mean or to get more information about what students are thinking.

Addressing commonly held ideas (Rating = Satisfactory)

Matter and Molecules addresses students' difficulty in appreciating the intrinsic motion of particles in solids, liquids, and gases in the Science Book (pp. T-21, T-34, T-35 [transparency]) and in the Activity Book (p. 5s, Question Set 1.3). Matter and Molecules addresses students' ideas that particles have macroscopic attributes, such as hardness, expansion, and physical state in the Science Book (pp. T-21–22, T-34–35, T-72, T-81–82) and in the Activity Book (Activity 6.2, pp. 33s, T-33; Activity 6.3, pp. 35s, T-35).

To address students' ideas, the material employs three strategies: (1) prompts students to react to commonly held misconceptions and contrast them with the scientifically correct idea (e.g., see the Activity Book, p. 33s, question 2); (2) elicits students' ideas and then juxtaposes them with the scientifically correct ideas (e.g., see the Science Book, p. T-72); or (3) suggests that teachers emphasize the correct response (e.g., see Science Book, p. T-21).

Strategy 2 may not be successful unless students are asked explicitly to contrast their ideas to the scientifically correct idea. Given the tenacity of students' misconceptions in the area of the kinetic molecular theory, it is not likely that strategy 3 (stressing the right response) will help many students to progress from their own ideas to the scientifically correct ones.

III. Engaging Students with Relevant Phenomena

Providing variety of phenomena (Rating = Satisfactory)

Overall, Matter and Molecules provides several opportunities for students to have experiences with everyday phenomena relevant to the key ideas. For example, with respect to key idea c (atoms and molecules are perpetually in motion), students observe and explain the dissolution of sugar in water; the fact that left overnight, sugar spreads evenly throughout the water (rather than rises to the top or settles at the bottom); the diffusion of gases (such as perfume, ammonia, and other smells); and the tendency of gases to occupy all of the space available to them (e.g., when the valve in a scuba tank is opened, the air rushes out and one can hear it making a rushing noise). However, the unit is uneven in the number and variety of experiences that it offers to support each key idea. It provides a large number and variety of experiences for the idea that molecules are perpetually in motion, the idea that increased temperature means increased molecular motion, and changes of state. However, it gives very few experiences for the different arrangement, motion, and interaction of molecules of solids, liquids, and gases. In Matter and Molecules, several phenomena are linked to the idea that matter is made of particles; however, these phenomena illustrate how perpetually moving particles can be used to explain a variety of phenomena. The material assumes that students have accepted the idea of particles, rather than trying to make the particulate nature of matter plausible. Although the material presents the compressibility of gases and links it to molecules, the focus of the presentation is on the idea that the spaces between molecules of gases are larger than the spaces between molecules of liquids, rather than on the existence of the spaces.

Providing vivid experiences (Rating = Excellent)

Matter and Molecules gives students an optimal number of firsthand experiences. For example, with regard to the idea that molecules are perpetually in motion, there are several hands-on experiences with phenomena that involve gases (such as the release of perfume and an inflated ball) and some additional experiences with phenomena that are not hands-on (such as the examples of ammonia and lemon smells that are conveyed in pictures and text) (see the analysis of Matter and Molecules for the previous criterion). The firsthand experiences are simple and of short duration (about 15 minutes), compared to the time that students spend describing their observations and explaining them in terms of molecules (30–40 minutes). The descriptions of experiences that are not firsthand are typically sufficient to help students form a mental picture of the experience. For example, after students had the experience with the diffusion of perfume, the text talks about the diffusion of ammonia and lemon smells. Although not particularly vicarious, students are likely to form a mental picture of the experience, because they have had the perfume experience very recently and have probably had several similar experiences with smells before.

IV. Developing and Using Scientific Ideas

Introducing terms meaningfully (Rating = Excellent)

Usually, Matter and Molecules presents terms in connection with a relevant experience. For example, the term “states” appears after students have had the opportunity to experience the change of state between solid and liquid water and to discuss the idea that ice and liquid water are the same substance (Science Book, p. 2s).

The technical vocabulary is restricted to the terms needed to discuss the important ideas. For example, in discussing the kinetic molecular theory, terms such as “amorphous,” “crystalline solid,” “cohesion,” “sublimation,” “viscosity,” and the names of gas laws are not introduced. These terms are found frequently in middle grades science textbooks, but they are not needed to discuss the key ideas.

Representing ideas effectively (Rating = Fair)

Matter and Molecules uses repeatedly the representation of molecules viewed through magic eyeglasses to give students a concrete picture of what the molecules might look like if they could see them. The use of magic eyeglasses may lead students to conclude that molecules are imaginary. Unfortunately, students are not asked to critique this representation or to compare it with the real thing. Drawings of molecules as seen through the magic eyeglasses represent the motion of molecules with arrows indicating the direction and motion of the molecules. Other drawings represent the different molecular arrangement and motion of molecules in the three states. Furthermore, an analogy compares the different molecular motion in the three states to students' motion in their seats, walking around the classroom, and free roaming after school (Science Book, p. T-34).

Most of the drawings—in particular, those of the arrangement and motion of molecules of solids and liquids—are not clear. This is due in part to the drawings themselves and in part to the poor printing (e.g., see Science Book, Transparency 2, p. T-30).

Generally, the representations are accurate. Unlike most other materials, Matter and Molecules typically represents the motion of molecules of solids and shows that substances are made of molecules (rather than displaying them floating in a colored background). However, some of the drawings that illustrate the relatively small size of molecules are likely to be misleading. For example, the drawing on page 7s of the Science Book shows a single cell floating in a drop of water with a border around the cell. The view through the magic eyeglasses does not make clear that the border is made of molecules.

The variety of representations for both the constant molecular motion and the different molecular arrangement and motion in solids, liquids, and gases is insufficient. Although there are some representations of these ideas, no animation or computer simulations are suggested to illustrate the different motions of solid, liquid, and gas molecules. The failure to represent dynamic processes is a deficiency.

Demonstrating use of knowledge (Rating = Excellent)

An important goal of Matter and Molecules is “helping students use [emphasis added] scientific knowledge to develop their own personal descriptions and explanations of real-world phenomena, and thus to appreciate how interesting and useful scientific knowledge can be” (Science Book, p. T-4). Throughout clusters 4–9, the Science Book demonstrates how knowledge about the arrangement, motion, and interaction of molecules can be used to explain everyday phenomena (pp. 28s, 32s, 35s, 36s, 41s, 42s, 44s, 48s, 54s, 57s, 60s). Most explanations provided are step-by-step (e.g., pp. 48s, 54s, 60s), are identified as demonstrations (e.g., pp. 41s, 44s, 48s, 54s, 60s), and include running commentary about important aspects of the explanation (e.g., pp. 41s, 32s). This is in stark contrast to most middle school science textbooks which either never explicitly show students how to link ideas to real world phenomena or provide incomplete explanations. Both the Teacher’s Guide and student text point to criteria for judging explanations of macroscopic phenomena that can be explained in terms of molecular arrangement and motion (e.g., Science Book, p. 32s).

Providing practice (Rating = Very Good)

Matter and Molecules is based on the premise that an “important part of teaching science consists of giving students the chance to practice their own descriptions and explanations” of natural phenomena. Therefore, the material “includes an Activity Book containing many questions that require students to write out descriptions or explanations” (Science Book, p. T-7). As a result, throughout Matter and Molecules, students are given opportunities to practice using the key ideas to explain a variety of phenomena that one would encounter in everyday life: air pumped into a bicycle tire, the expansion of sidewalk joints, heating to loosen a jar lid, expansion of the liquid in a thermometer, etc. In addition, the Matter and Molecules Science Book recommends procedures that teachers can use to ensure that all of the students in the class get feedback. Although, overall, Matter and Molecules provides numerous tasks for students to practice their understanding of the key ideas, not enough tasks relate to the different arrangement and motion of molecules in the three states (solid, liquid, and gas). For example, only once are students asked to use the idea of the different molecular arrangement and motion in solids, liquids, and gases to explain the different properties of the three states.

V. Promoting Students' Thinking about Phenomena, Experiences, and Knowledge

Encouraging students to explain their ideas (Rating = Excellent)

The Activity Book includes in every lesson cluster at least one set of activity sheets containing questions that prompt students to express, and sometimes justify and represent, their ideas. For example, in Lesson Cluster 4, students are asked to express their ideas on whether it would be easier to push the molecules together in a gas or in a liquid, justify their responses, and represent their thoughts about how molecules of air would be arranged in a syringe when the plunger is all the way out (Activity Book, pp. 18–19s). In addition, every lesson cluster includes a set of overhead transparencies that are designed to help teachers develop class discussions about the key ideas in the unit (Science Book, pp. T-9, T-53). The material provides opportunities for each student to state his or her views by including activity sheets on which all students are asked to record their ideas about the questions posed. The importance of giving feedback to students is stressed in the Introduction to the Science Book (p. T-6), and several mechanisms for providing feedback to students are proposed. In addition, the student book includes text that can give students feedback on their ideas about the activities. After students describe and explain phenomena using their own ideas on the activity sheets, they are frequently asked to read the text that explains the phenomena they observed (Activity Book, pp. 25–26s; Science Book, pp. 34–35s, 43s). Moreover, in contrast to curricular materials that merely state that “student answers will vary” or “provide the correct answer,” the teacher notes in Matter and Molecules often include brief descriptions of likely erroneous answers, the misconceptions on which they are based, and how the teacher can respond to them.

Guiding student interpretation and reasoning (Rating = Excellent)

Matter and Molecules routinely provides question sequences to help students interpret their activities. The questions are structured carefully in order to lead students step-by-step from one insight to another (e.g., Activity Book, pp. 18–20s, 25–26s, 31–32s). Questions frame important issues, help students relate their experiences with phenomena to the scientific ideas presented, or prompt students to contrast common misconceptions with their scientific alternatives.

Encouraging students to think about what they have learned (Rating = Poor)

Matter and Molecules does not include self-monitoring as a strategy. Despite the explicitness of the introductory notes to the teacher with respect to other strategies, self-monitoring is not mentioned. In a few instances, students are asked to revise their explanations of phenomena based on what they have learned (see the Activity Book, p. 23s, question 4; Activity Book, p. 29s, question 3). But overall, Matter and Molecules does not give students opportunities to monitor their own understanding.

VI. Assessing Progress

Aligning assessment to goals (Rating = Very Good)

Most of the questions in the Cumulative Tests focus on the key ideas that relate to the particulate nature of matter. Students are asked to describe, predict, and explain substances and phenomena in terms of the arrangement and motion of invisible molecules. For example, students (a) describe how ice, water, and water vapor are different when one looks at them through magic eyeglasses (Test 1, item 3), (b) predict and explain what happens to a chunk of steel left on the sidewalk on “a very hot and sunny day” (Test 2, item 3), (c) explain what happens to a glass of water left uncovered on a table for a week (Test 2, item 5), (d) describe and explain what happens when they smell ammonia, perfume, skunks, or anything that is smelly (Test 2, item 7), and (e) explain why they can’t see air (Test 1, item 2).

Successful responses to these questions (and to other questions in the Cumulative Tests) require the specific key ideas. For example, the following items require that students know the different arrangement and motion of molecules in solids, liquids, and gases:

Describe the ways in which ice, liquid water, and water vapor are different when you look at them through magic eyeglasses. Draw pictures if you want to, but also use words. (Test 1, item 3)
Draw pictures of what you might see if you looked with magic eyeglasses at ice and the puddle of water under the melting ice. (Test 2, item 4b)

A few of the key ideas are not adequately assessed in Matter and Molecules. For example, only two questions are relevant to the idea that “increased temperature means greater molecular motion” and only one of these questions probes further to get at the idea of thermal expansion. Students explain why a piece of candy dissolves faster in hot water than in cold water and are prompted to talk about substances and molecules (Test 2, item 6). They also predict and explain what will happen to a solid chunk of steel that sits outside on a very hot day (Test 2, item 3). In the latter question, students are not prompted to provide a molecular explanation and might legitimately state that substances expand when heated (even though a molecular explanation is desired according to the suggested response in the Teacher’s Guide pages).

Testing for understanding (Rating = Satisfactory)

Like the questions within the unit, the Cumulative Test questions emphasize application of the kinetic molecular theory to describe, predict, and explain everyday phenomena. All of the questions described under the previous criterion focus on application of the key ideas chosen for this study, as do other questions: students describe what molecules are (Test 1, item 4), explain why they can see trees but cannot see the molecules the trees are made up of (Test 1, item 5), explain why they can push air in a syringe (Test 1, item 6), and tell what the smell of soup cooking on the stove tells them about the molecules in the air (Test 1, item 7). These application questions contain both classroom contexts (e.g., describe the ways in which ice, liquid water, and water vapor are different when you look at them through magic eyeglasses) and everyday life contexts (e.g., explain why a cold soda can fogs up when it sits on the table).

The Cumulative Tests ask students to draw molecules and to describe and explain familiar phenomena. Most items that target the key ideas have been introduced earlier in the unit and are likely to be familiar to students. For example, the explanation of why a piece of candy dissolves faster in hot water than in cold water is introduced in Lesson Cluster 6 in the Science Book and the explanation of how it is that molecules of smelly substances can move through the air and get to students’ noses is discussed in the Activity Book.

To judge whether students are able to transfer what has been learned (and not only the comprehension of what was taught), the tests should include more novel tasks. (One might argue that students do not really apply the kinetic molecular theory to explain phenomena and can answer simply by memorizing the explanations in the Science Book.)

Using assessment to inform instruction (Rating = Satisfactory)

Matter and Molecules includes quality questions throughout the unit and provides sufficient information to help the teacher interpret students’ responses and diagnose remaining difficulties. However, specific suggestions about how to address these persistent difficulties are hardly provided in this material.

The Teacher’s Guide indicates that “the last question set in each lesson cluster contains questions reviewing the content of the entire lesson cluster. If you grade those question sets, which are packaged separately so that they can be taken up or used as tests, you should be able to do an adequate job of monitoring the progress of individual students” (Science Book, p. T-8). The questions provided are specific enough to monitor students’ understanding. For example, students are asked to draw water molecules and indicate with arrows how they are moving, and to explain why they agree or disagree with the claim that ice molecules stop moving in the freezer (Activity Book, p. 5, Question Set 1.3, items 3, 4, and 5). They are asked how ice, liquid water, and water vapor are different (Activity Book, p. 6, Question Set 1.4, item 2), and what happens when they smell (Activity Book, p. 16, Question Set 3.3, items 3 and 4). In Question Set 4.4, students are asked to explain why the plunger of the syringe moves back out after they let go of it (Activity Book, p.23, item 4), in Question Set 6.4 students are asked to explain what happens when substances are heated and cooled and why heating the metal ring (in the ball and ring experiment) would help to get the ball through it (Activity Book, p. 38, items 1 and 2).

Many of these questions are designed to probe whether students still hold particular misconceptions. For example, the question “My friend says that when water freezes the molecules get cold and turn hard. Do you agree? Explain your answer” (Activity Book, p. 6, Question Set 1.4, item 3) anticipates students’ naive attribution of observable properties to the invisible molecules. In the same way, the following question gets at students’ naive ideas that heat is matter (and hence made up of molecules) and that when a substance expands, the molecules themselves get bigger:

Three of my friends were arguing about why heating the metal ball made it bigger. This is what they said:
Barry: The ball gets bigger because the heat makes the metal molecules expand.
Mary: The ball gets bigger because you are adding heat molecules to the ball.
Terry: The metal molecules are still the same size but they move farther apart.
Who was right? Why do you think so? [Activity Book, p. 33, Question Set 6.2, item 2]

The Teacher’s Guide includes information that can help teachers to diagnose their students’ difficulties. For example, after students perform the ball and ring experiment, they are asked to summarize the main points of the lesson by writing a sentence about heating solids and a sentence about cooling solids. They are prompted to mention changes in both substances and molecules (Activity Book, p. 33, Question Set 6.2, item 1). In addition to the correct/desired answers, the Teacher’s Guide states:

Some students say that molecules become hot when solids are heated, which is not true—only the substance becomes hot. Students may also say that molecules expand, but molecules only move farther apart—the substance expands. This naive conception is held by “Barry” in question #2 on this page. [emphasis in the original] [Activity Book, p. T-33, item 1]

Unfortunately, while teachers are encouraged to “review or reteach ideas that your students are having trouble understanding, as revealed by their performance on the review question sets or the tests” (Science Book, p. T-8), the material rarely provides specific suggestions about how to address persistent difficulties students have. In one case, a Teaching Suggestion specifies: “After the students have completed this question set, you might want to use the transparency “How are molecules arranged and how do they move?” or the poster to discuss the students’ answers” (Activity Book, p. T-10).

In another case, students are asked to list the most important things they learned from the lesson cluster (Activity Book, Question Set 5.3, item 4), and teachers are advised to write all students’ responses (correct and incorrect) on the board and have students discuss those they feel are incorrect (p. T-30, item 4). Occasionally, teachers are told that an idea will be dealt with later in the unit. For example, in Question Set 1.3, students are asked whether they agree that ice molecules are perfectly still. Teachers are told that “[s]tudents sometimes think that molecules of ice are not moving because ice is so hard… .This is a difficult idea to grasp, but it will come up again in Lesson Cluster 7 on melting and solidifying” (Activity Book, p. T-5, item 5).

VII. Enhancing the Science Learning Environment

Providing teacher content support (Some support is provided.)

The material provides minimal support in alerting teachers to how ideas have been simplified for students to comprehend and what the more sophisticated versions are. Content background notes in the Teacher’s Guide often provide detailed explanations of key ideas and student thinking about those ideas, especially in areas where students may have difficulty (e.g., Science Book, pp. T-3–6, T-12–14, T-26–27). In addition, content background notes often highlight main ideas for lessons (e.g., Science Book, pp. T-24 and T-31) and occasionally relate key points of a lesson cluster to previous lesson clusters (e.g., pp. T-48 and T-79). While content background notes sometimes provide sophisticated versions of ideas (e.g., Science Book, pp. T-18 and T-89), the advanced explanations rarely alert teachers to how ideas have been simplified for students (e.g., Science Book, p. T-70). Overall, the teacher content support provides a comprehensive content resource at the sophistication level of students.

The material generally provides sufficiently detailed answers to questions in the student book for teachers to understand and interpret various student responses. Most answers include expected scientific responses, potential student naive ideas, and ways these ideas may be addressed (e.g., Activity Book, pp. T-1, item 4 and T-22, item 1). In addition, the material provides “Key Elements of a Good Description” at the beginning of each lesson cluster (e.g., Science Book, pp. T-11 and T-26). In a few instances, however, answers are brief and require further explanation (e.g., Activity Book, pp. T-10, item 1a and T-49, item 1).

The material does not provide support in recommending resources for improving the teacher’s understanding of key ideas.

Encouraging curiosity and questioning (Some support is provided.)

The material provides general suggestions for how to encourage students’ questions but gives little support in guiding their search for answers. Introductory teacher notes suggest that students generate questions to help increase their comprehension of text passages (Science Book, pp. T-6–7).

The material provides many suggestions for how to respect and value students’ ideas. Introductory notes in the Teacher’s Guide (Science Book, pp. T-8–9) and student text (Science Book, p. 1s) generally address the importance of eliciting and valuing students’ ideas. Within specific lesson clusters, teacher notes often take into account and explicate student naive ideas (e.g., Science Book, p. T-37; Activity Book, pp. T-26, items c–e). At times, teacher notes state that multiple student answers should be acceptable for selected questions (e.g., Activity Book, pp. T-10, items 1a–b and T-46, items 1, 2, and 4), and the material often asks students to record their own ideas in tasks (e.g., Activity Book, pp. 1s, items 1, 3, and 4 and 31s, item 1).

The material provides some suggestions for how to raise questions such as, “How do we know? What is the evidence?” and “Are there alternative explanations or other ways of solving the problem that could be better?” However, it does not explicitly encourage students to pose such questions themselves. Specifically, the material includes some tasks that ask students to provide evidence or reasons in their responses (e.g., Activity Book, pp. 13s, item 6 and 27s, item 3).

The material provides some suggestions for how to avoid dogmatism. The student text generally portrays the nature of science as a human enterprise in which students may participate (e.g., Activity Book, pp. 4s, items 4–5 and 29s, items 1–3). In addition, the student text explains how students and scientists may think about certain ideas (Science Book, pp. 5s and 8s). However, the material contributes to dogmatism by providing little attention to the work of particular, practicing scientists and changes over time in scientific thinking. Also, the number of drawings that include people throughout the material are few (e.g., Science Book, pp. 29s, 56s).

The material does not provide examples of classroom interactions (e.g., dialogue boxes, vignettes, or video clips) that illustrate appropriate ways to respond to student questions or ideas. However, a limited sense of desirable student-student interactions may be gained from procedural directions for laboratories and cooperative group activities (e.g., Science Book, pp. T-7–9; Activity Book, pp. T-1 and T-27, Teaching Suggestions).

Supporting all students (Some support is provided.)

The material generally avoids stereotypes or language that might be offensive to a particular group. In addition, the material’s use of multiple writing genres, including traditional expository text and some narrative forms (e.g., Science Book, pp. 50–52s and 68–69s; Activity Book, p. 33s, item 2), may support the language use of particular student groups.

The material does not provide illustrations of the contributions of women and minorities to science and as role models. However, cultural references are included in a few text passages (e.g., Science Book, pp. 29s and 50s).

The material suggests multiple formats for students to express their ideas during instruction, including cooperative group activities (e.g., Science Book, pp. T-7–9), laboratory investigations (e.g., Activity Book, pp. 25–26s), whole class discussions (e.g., Science Book, p. T-15, Teaching Suggestions), essay questions (e.g., Activity Book, p. 50s, item 4), creative writing (e.g., Science Book, p. T-109, Teaching Suggestions), and drawing (e.g., Activity Book, p. 7s, item 2). In addition, a few formats are suggested for assessment, including essay (e.g., Activity Book, p. 59s, item 6) and drawing (e.g., Activity Book, Cumulative Test 1, p. 3s, item 9c). However, the material does not usually provide a variety of alternatives for the same task.

The material does not routinely include specific suggestions about how teachers can modify activities for students with special needs. However, the Teacher’s Guide provides a few additional extension activities (e.g., Science Book, pp. T-35 and T-86) similar in complexity to those in the student text.

The material provides many strategies to validate students’ relevant personal and social experiences with scientific ideas. Introductory teacher notes state one goal of the material as helping “students use scientific knowledge to develop their own personal descriptions and explanations of real-world phenomena, and thus to appreciate how interesting and useful scientific knowledge can be” (Science Book, p. T-6). Throughout the material, examples from students’ everyday lives are used, and their importance is often emphasized (e.g., Science Book, p. T-94, Teaching Suggestions). Many text sections relate specific, personal experiences students may have had to the presented scientific concepts (e.g., Science Book, p. 53s). In addition, many tasks ask students about particular, personal experiences they may have had or suggest specific experiences they could have. For example, after a student text reading about complex solutions, teacher notes suggest asking students to collect labels from complex solutions at home. The class then discusses why the home items are considered complex solutions (Science Book, p. T-65, Teaching Suggestions).