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AAAS  :: Project 2061  :: Textbook Evaluations

Middle Grades Science Textbooks: A Benchmarks-Based Evaluation

BSCS Middle School Science & Technology: Diversity and Limits, Level B. Kendall/Hunt Publishing Company, 1999
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 = Fair)

Units and chapters begin with a two-page picture, introductory text, and a list of chapter or section titles. The introductory text typically provides a clear and easily understandable purpose (see, for example, pp. 159s, 163s, 179s, 191s, 215s). However, the purposes are not presented in ways that make them interesting or motivating to students, nor are students asked regularly to think about them. Often, two purposes are presented, but only one is consistently addressed throughout the chapter or the sections within the chapter, which could be confusing. For example, two purposes are provided for Unit 2: Why Are Things Different?: (1) to learn how to make and test scientific explanations, and (2) to understand more about how things are different. Since lessons within chapters only occasionally focus on how things are different, the second purpose is met inconsistently. In other instances, the purpose provided does not accurately describe the following lessons. For example, the purpose provided in Chapter 10: Using Scientific Models to Answer Questions states that students will study "the characteristics of materials and why materials are different" (p. 191s). However, most of the lessons in this chapter focus on learning to develop, use, and modify a model. For the lessons that focus on the characteristics of materials, only two different materials are explored: water and air. Students find out that water can evaporate, that food coloring diffuses faster in hot water than cold water, that air in a balloon expands when heated, and they explain these behaviors with the particle model (pp. 201−207s). There is no explicit discussion about other materials behaving differently. Interestingly, even the last section in the unit (entitled Connections: Properties and Models in Review [p. 241s]) does not tie together the modeling process and why things are different. At best, it asks students to define what a property is and summarizes the chapter by saying that they used their knowledge of the particle model to create their own models for why things have certain properties (p. 241s). But there is no mention of the original question asking "how and why things are different."

Conveying lesson/activity purpose (Rating = Satisfactory)

The purpose of the investigations is conveyed consistently to students and should be comprehended easily. Without fail, the teacher's notes provide the purpose of readings to teachers, but only sometimes does the student text convey the purpose of the readings to students. Rarely are students asked to think explicitly about the purpose of investigations and readings. In addition, investigations and readings are not always connected clearly and well to the unit purpose or purposes. In the beginning or at the end of a section, the material frequently conveys to students what they have just learned and what they are about to do or learn next.

Justifying lesson/activity sequence (Rating = Satisfactory)

Both the unit overview and chapter overviews in Unit 2: Why Are Things Different? provide an outline for the unit and the chapters. The chapters are ordered in a clear and comprehensible way, as are the sections within them. However, there is no explicit or detailed rationale for why the chapters within the unit and the sections within the chapters are sequenced the way they are. Granted, the Program Overview and Goals section in the Teacher's Edition explains that all of the student activities in the program are sequenced according to an instructional model characterized by the so-called five E's (Engage, Explore, Explain, Elaborate, Evaluate [p. xvii]), and that all of the chapters in unit 2 include sections that correspond to the five E's (see endnote). However, the sequence of the sections (based on the chapter overviews and the outcomes and indicators of success for each section in the chapter) does not reflect the rationale of the five E's instructional model, which is to take one concept through the cycle of the five E's. Instead, different sections (i.e., different E's) focus on different concepts. For example, in chapter 10, students are to be "engaged in the idea that a person can never be certain about what is inside an object or material unless that person is able to see directly inside (p. 191a)," but are to "elaborate their understanding of the particle theory of matter and their understanding of scientific models by using the model to help explain certain phenomena (p. 191a)" (emphasis in original).

In addition, when the order of the activities is examined closer, several issues can be raised with regard to the sequence of particular sections or activities within sections. For example, Chapter 9: Scientific Explanations Are Ancient History focuses on ancient explanations related to the concept of "elements," but this topic seems extraneous because it is not continued in the rest of the unit. The next chapter, chapter 10, introduces  part of the particle model, specifically, just the idea that "matter is made up of particles" (Idea a). Then students are asked to explain a variety of phenomena that cannot be explained only with this idea. Other ideas such as that particles are in constant motion (Idea c) and that they move farther apart when heated (Idea d) are needed to make sense of why a balloon gets larger when heated and why food coloring spreads out in water (pp. 201-205s). In the next few pages, the particle model is revised, and the revised model is shown to explain these phenomena (pp. 206-207s). This sequence is likely to confuse students and is an inaccurate representation of the scientific process. A logical sequence should show that the model has success in explaining some phenomena before showing that it cannot explain other phenomena. Otherwise, models that do not explain phenomena are discarded rather than revised. This happens again when students are asked to explain some chemical reactions from an earlier chapter (p. 207s). They are to conclude that the model is incomplete before they develop confidence in their model by showing that it can explain further observations (such as the "Coin-Dancers" and the "Rainmakers") (pp. 208−212s).

With regard to this sequencing criterion, one review team gave the material a  "satisfactory" rating, but the other team gave it an "excellent" rating. Although the second team acknowledged weaknesses in unit 2's sequencing of activities, it felt that the material meets both indicators for this criterion (namely, that the material provides a rationale for a logical or strategic sequence of activities, and that the sequence of activities reflects the stated rationale) and hence, should receive an "excellent" rating. Given the weaknesses in the material's sequence of activities described above and also that the sequence of the sections does not reflect the rationale of the five E's instructional model, the Project 2061 staff recommends a satisfactory rating.

II. Taking Account of Student Ideas

Attending to prerequisite knowledge and skills (Rating = Poor)

Diversity and Limits does not alert teachers to important prerequisite ideas, nor does it address a number of prerequisites necessary to understanding the key physical science ideas. Although the first chapter in unit 2 (Chapter 8: Properties of the Material World) provides opportunities for students to experience the properties of materials and to begin to question how these properties can be explained by what is "inside" the materials, no other prerequisites are addressed. Missing prerequisites include knowledge of what matter is, whether air is matter, and that collections of pieces have properties that the individual pieces do not have.

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

Diversity and Limits mentions a few of the ideas commonly held by students. For example, in the investigation about air expansion in a balloon, the Teacher's Edition states that "you might discover they [students] hold the common misconception that the individual particles are getting larger as they get hotter" (p. 191bt). However, the statement does not emphasize these misconceptions, nor does it explain them in detail. In this instance, it fails to note that students generally attribute the observable properties of substances (such as hardness, hotness, coldness, and expansion) to particles (such as that particles of ice are cold) (Johnston & Driver, 1989; Lee, Eichinger, Anderson, Berkheimer, & Blakeslee, 1993, pp. 249-270). Moreover, the Teacher's Edition does not alert teachers to other well-documented and important difficulties that students have. For example, research on student understanding of the structure of matter reveals that many students think that particles (atoms or molecules) are in substances and/or that there is something (e.g., air) between the particles, rather than that substances consist of nothing except molecules with empty spaces between them (Brook, Briggs, & Driver, 1984; Nussbaum, 1985; Lee et al., 1993).

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

Although the material includes several questions or tasks that could provide an opportunity for the teacher to identify students' ideas, they are not indicated as such in the student text or in the instructions to teachers. Furthermore, there is no indication in the text that eliciting students' ideas can help teachers decide what ideas to build on and what changes to promote. Hence, even if teachers notice that students have alternative ideas as a result of using the relevant questions in the material, they may ignore them altogether.

Addressing commonly held ideas (Rating = Poor)

Students' misconceptions in two instances are addressed explicitly. In Patterns of Change (level A), the text states that "[p]eople often think that when water evaporates, it disappears, but, in fact, the small particles of water are now in the air" (p. 254s). Similarly, in Diversity and Limits (level B), the teacher's notes state that "you might want to explain to the students that according to the theory, all particles are in motion-even the particles that make up the solids.. Also be sure the students understand that the particles themselves are not hot or cold" (p. 207t). However, merely stating the correct response is not likely to help students progress from their initial ideas. Moreover, the material does not address several of the important areas of difficulty noted in research studies, such as that students often think that particles are in substances, rather than that substances are made of particles and that there is something (air, for example) between the particles (Brook, Briggs, & Driver, 1984; Nussbaum, 1985; Lee et al., 1993).

III. Engaging Students with Relevant Phenomena

Providing variety of phenomena (Rating = Poor)

Overall, the number and variety of phenomena included to support the key ideas are not adequate. There are several problems with the selection of phenomena, how they are explained, and the sequence in which they are introduced. For example, there are several phenomena that students are asked to explain using the idea that all matter is made of particles (Idea a). However, these phenomena (for example, a balloon increasing size as it is warmed, and food coloring spreading out in water [level B, pp. 201-205s]) cannot be explained by this key idea alone; other key ideas are needed. Since these other ideas are not provided until later in the chapter, students will likely be confused by their inability to explain these phenomena. Thus, no phenomena are provided to make this key idea plausible to students (see also the above criterion, or segment, entitled "Justifying activity/lesson sequence"). Furthermore, also lacking are phenomena, such as the compressibility of gases, that could make the existence of particles (Idea a) plausible to students who do not believe the idea already.

Some phenomena are provided that support the idea that increased temperature means greater particle motion (Idea d); however, phenomena are not provided that can be explained in terms of the expansion of solids or liquids. In addition, phenomena are presented for the idea that there are attractive forces among particles in liquids (part of Idea e2). However, there is little variety, and most phenomena focus on surface tension. Very few experiences are presented to support the idea that particles are perpetually in motion (Idea c) or to illustrate changes of state (Idea f). No phenomena are included on the arrangement and motion of particles in solids, liquids, and gases (Idea e).

The choice of phenomena is a general weakness in level B's Unit 2: Why Are Things Different? Most phenomena included are too complex for middle school students (for example, the chemical reactions presented in chapter 9, or the surface tension phenomena presented in chapter 11).

Providing vivid experiences (Rating = Satisfactory)

Most of the phenomena are presented to students in hands-on activities. Hence, although there is little variety in the phenomena, students are likely to form a mental picture of those that are included. One review team was concerned that the rather large amount of time involved in doing the activities is inefficient for the number of ideas addressed. Although important, this issue is hard to resolve: It is difficult to estimate the efficiency of the material, because it attempts to address both the particulate nature of matter and the use of scientific models to predict and explain phenomena.

IV. Developing and Using Scientific Ideas

Introducing terms meaningfully (Rating = Very Good)

The use of technical terms is limited, and almost all of the terms introduced are linked to relevant experiences. An exception is the introduction and use of the term "particle." When "particle" is used initially, it is not connected to any experiences, nor is it defined in any way. Furthermore, the word is used interchangeably to refer variously to  subatomic particles, atoms, and molecules, which might be both misleading and confusing to students (pp. 195-198s).

With regard to this introducing-terms criterion, one review team gave the material an "excellent" rating, but the other team gave it a "very good" rating. Given the weakness in the material's introduction and use of the term "particle," the Project 2061 staff recommends a "very good" rating.

Representing ideas effectively (Rating = Poor)

No drawings (or other representations) are used to help students understand the arrangement, motion, or interaction of particles in the phenomena they are studying. Only one representation of forces between particles in liquids is presented (pp. 207t-207at).

Demonstrating use of knowledge (Rating = Poor)

Although the material demonstrates how to use models to explain observations and points to what a good explanation/model is in general, it does not show students good examples of explanations using the key physical science ideas. Only two instances were identified in which explanations using the particle model are explicitly given to students. In the first instance, the teacher's notes provide a step-by-step explanation of diffusion of food coloring in water, and the instructions to the teacher suggest that this explanation will be conveyed to students (p. 207t, item 1). In the second instance, the text gives a step-by-step explanation about why many drops of water can fit on the surface of a penny (pp. 238-239s, part D). But overall, students are asked to explain various phenomena in terms of the particle model, but will not know how to do so; they are left with their own explanation. The learning approach in this material expects students to construct explanations without having models of good explanations to use as examples.

With regard to this criterion about demonstrating use of knowledge, one review team gave the material a "poor" rating, but the other team gave it an "excellent" rating. According to the second team, "The material does an outstanding job of demonstrating how to construct and critique a scientific explanation. This includes demonstrations of how to design an investigation, how to use ancient explanations to explain properties of materials, how to use observations as evidence in support of a model, how to revise a model on the basis of new information, how to make predictions on the basis of a model, how to construct if-then statements to express predictions made on the basis of a model, and how to critique a scientific explanation."

In response to this statement, the first team pointed out that students are asked to explain various phenomena in terms of the particle model, but they will not know how; rather, they are left to arrive at their own explanations. This evaluation focuses on whether Diversity and Limits provides instructional support for the idea that "all matter is made of particles" and not for students' ability to develop and use models. Consequently, to satisfy this criterion, the material needs to "demonstrate how to explain different phenomena using the particle model." Although Diversity and Limits attempts to demonstrate how to use models and points to what a good explanation or model is in general, it does not show students explicitly good examples of explanations using the particle model. Therefore, the Project 2061 staff recommends a "poor" rating for this criterion.

Providing practice (Rating = Poor)

Overall, there are a limited number and variety of opportunities for students to practice using the key ideas. The material encourages students repeatedly to construct explanations of observations based on the particle model. However,  based on the instructions in the teacher's notes, it is likely that (at least in some instances) students will be developing "alternative" explanations that will not be compared and contrasted with the scientifically correct explanations. For example, the teacher's notes state: "[W]hat the teams come up with is not nearly as important as the process they use. Did they base their predictions on their models? Did they appropriately revise their models to account for new observations?" (pp. 221-222t). Hence, it appears that the focus is on practicing the creation of models that fit the observations at hand (even if they are erroneous), rather than on practicing using the particle model in constructing scientifically correct explanations. Nevertheless, the material provides some opportunities for students to practice the ideas that all matter is made of particles (Idea a) (e.g., pp. 207s, 210s), and that increased temperature means increased particle motion (Idea d) (e.g., pp. 207s, 211s). There is one opportunity for students to explain a phenomenon that involves evaporation of water (part of Idea f) (p. 211s). Students are not asked to apply the ideas that particles are extremely small (Idea b) and in perpetual motion (Idea c), or the different arrangement and motion of particles of solids, liquids, and gases (Idea e).

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

Encouraging students to explain their ideas (Rating = Satisfactory)

There are numerous opportunities provided for students to express and share ideas in writing and in a group, as well as present to their ideas to the class (e.g., pp. 203-204s, 207s, 211s, 220s). Students are only sometimes asked to clarify, justify, or represent ideas with respect to the particle model (e.g., pp. 203-204t, p. 207s item 6). There are more opportunities to clarify ideas with respect to the use of models in general. Only occasionally are suggestions included in the teacher's notes about how to give feedback to students (e.g., p. 210t).

Guiding student interpretation and reasoning (Rating = Satisfactory)

The material consistently includes questions to help students think about the observations they make and the text they read. Questions typically ask students to explain the phenomena presented to them using the particle model. The material does not include carefully structured sequences of questions to scaffold students' drawing inferences from observations that often relate to quite complex phenomena (e.g., pp. 207s, 211s).

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

In several instances, students appear to be monitoring the usefulness of the model or models they are developing but not their understanding of the scientifically accepted particle model (e.g., p. 207s, item 7; p. 212s). Although students are sometimes asked to revise their ideas based on new observations (e.g., pp. 220-224s), they are not asked to evaluate their ideas against scientifically correct ideas. One review team was concerned that in chapter 10 the progression of the particle model that Diversity and Limits suggests is not necessarily the one that students would use, and that giving them the steps takes the self-monitoring out of their hands: "Students cannot say this is how my thinking changed. They were never allowed to have alternative views."

The rating given above for this encouraging-students criterion is the average of the ratings of the two review teams (the individual team ratings were "poor" and "satisfactory"). The teams debated the question of what students are asked to monitor in Diversity and Limits: their understanding of the particle model ideas (key ideas) or the usefulness of their models. The first team pointed out that students do not evaluate their ideas against what is known, that the progression of the particle model that the material suggests is not necessarily the one that the students would use, and that giving them the steps takes the self-monitoring out of their hands. The second team objected that the clarification of the criterion that was available to reviewers does not say explicitly that students need to check their own progress against "what is known."

This evaluation focuses on whether Diversity and Limits provides instructional support for the idea that "all matter is made of particles" and not for students' ability to develop and use models. Therefore, to satisfy this criterion, the material needs to engage students in monitoring their progress in understanding the particle model. While it is true that the clarification document does not state explicitly that materials need to encourage students to check their progress against "what is known," students appear to monitor mostly whether their models fit the observations at hand, and hence, whether the process they used to build their models was adequate (rather than whether the actual models, and hence, their understanding of the particle model are adequate). Therefore, the Project 2061 staff recommends a "fair" rating for this criterion.

VI. Assessing Progress

Aligning assessment to goals (Rating = Poor)

Diversity and Limits lists a variety of assessment tools to be used at the end of instruction: performance assessment activities, evaluate activities, the level B test, cumulative portfolios, and projects (Teacher's Resource Book, level B, p. 33). There are no chapter or unit tests provided. Unfortunately, many of the items provided in these tools do not focus on the key physical science ideas. In fact, only two assessment items are somewhat related to the key physical science ideas. For the idea that all matter is made of particles (Idea a), students describe the evidence scientists have for the particle model (level B, p. 241s, item 2). For the idea that particles are in constant motion (Idea c), students are asked to explain what happen when colored water is added to salt and sugar solutions of increasing concentration, and to then decide whether the particle model was helpful in the explanation (Teacher's Resource Book, pp. 17a-17c). However, the particle-model question requires more sophisticated physical science ideas, such as knowledge about concentrations, so students might fail to respond successfully even though they understand the constant motion of particles.

None of the other key physical science ideas-such as the idea of different arrangement and motion of molecules in the solids, liquids, and gases (Idea e)-are assessed.

Testing for understanding (Rating = Poor)

Unfortunately, very few of the questions provided require students to apply the key physical science ideas. The questions provided do not ask students to explain phenomena, identify examples for the general principle, or make predictions. While the two tasks described under the previous criterion focus on understanding (as opposed to recall of text information), this is not sufficient for the entire set of key physical science ideas.

Using assessment to inform instruction (Rating = Poor)

Diversity and Limits lists several opportunities for formative assessment, including the Stop and Think questions in the text, the notebook entries, homework, portfolios, evaluate activities, and cooperative learning checklists (Teacher's Resource Book, level B, p. 33). However, very few of the questions and tasks in these components focus on the key physical science ideas.

A few tasks could be used to assess students' progress in understanding the particle nature of matter (Idea a). One question asks students to describe the evidence scientists have for the particle model (level B, p. 241s, item 2). Other questions ask students to use the particle model to explain phenomena such as a coin placed on the rim of a bottle that moves when the bottle is placed in hot water (but not when placed in cold water) (p. 210s, item 14) and what happens when a flask filled with cold colored water is placed in hot water (pp. 210-211s, item 8). For questions like these, found in the Evaluate sections, the introductory material encourages teachers to ask questions such as "Why do you think.? What evidence do you have? What do you know about x? How would you explain x?" (p. xviiit). Unfortunately, teachers are not reminded of these questions in the Evaluate sections throughout the chapters, so this advice may go unheeded. Occasionally, teachers are reminded to motivate the students to provide supporting statements for their answers (e.g., p. 210t). However, overall, the material does not include suggestions for teachers about how to interpret students' responses, nor does it include specific suggestions about how to use students' responses to make decisions about instruction.

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. Teacher Background Information notes provide sophisticated versions of ideas for selected student text and activity sections. The advanced explanations often do not explicitly alert teachers to how ideas have been simplified for students (e.g., p. 179at) or are incomplete (e.g., pp. 191a-191bt). Overall, the Teacher Background Information may be used by the teacher as a selective, but not a comprehensive, content resource.

The material generally provides sufficiently detailed answers to questions in the student text for teachers to understand and interpret various student responses (e.g., pp. 204-205t, Wrap Up, item 2). However, there are some limitations to the responses provided in the teacher's notes, which occasionally are incomplete (e.g., p. 207bt, Wrap Up, items 5, 7).

The material provides minimal support in recommending resources for improving the teacher's understanding of key ideas. The Teacher's Edition includes a list of "Websites of Interest" with brief, bulleted descriptions and recommendations at the beginning of each chapter (e.g., pp. 191c-191dt) and a list of "Educational Technology Resources" (software, CD-ROMs, videos, and laser discs) with recommendations but not descriptions at the beginning of each unit (e.g., pp. 161b-161dt). A reference list subdivided by unit without annotations is also provided at the end of the Teacher's Edition (pp. 417-418t). Limited descriptions of references in the Teacher's Edition identify topics addressed, but none of the references are explicitly linked to specific text sections or key ideas. In addition, the Teacher's Resource Book has a Background Resources section that includes commentary on science standards documents and general references on learning and assessment strategies.

Encouraging curiosity and questioning (Some support is provided.)

The material provides some suggestions for how to encourage students' questions and guide their search for answers. While the material emphasizes student questions, as in ending a reading with a discussion of students' ideas and questions (e.g., p. 180t, Strategies), it gives less attention to guiding students' search for answers. Often, no teacher's notes are provided for how to address the lists of questions generated by students. However, a few instances of guiding students' search for answers are to be found in the material, including directions for matching student questions with relevant technology references from the resource lists (p. 180t, Further Opportunities for Learning).

The material provides some suggestions for how to respect and value students' ideas. Teacher's notes often stress that multiple student answers should be acceptable for questions (e.g., p. 184t, Wrap Up). However, this may have implications for other criteria (see segment above entitled "Providing practice"). The skills identified as "Be open to others' ideas" (e.g., p. 192s, Working Cooperatively) and "Let others finish without interrupting" (e.g., p. 208s, Working Cooperatively) are stated in multiple places in the student text and teacher's notes as new cooperative group skills. However, other than stating the skills, the material does not usually provide students with any further support in how to enact the skills within their cooperative groups.

For the particle model of matter, the material provides many 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?" (e.g., p. 198s). However, the material does not routinely encourage students to pose such questions themselves.

The material provides some suggestions for how to avoid dogmatism. For example, the student text portrays the nature of science as a human enterprise in which students may participate (e.g., pp. 172-174s, Investigation: How Can I Learn More about That Property?). In addition, the material includes the work of particular, practicing scientists (e.g., pp. 185-188s, Reading: Elements of Explanations), and describes changes over time in scientific thinking about explanations of differing material characteristics (pp. 195-198s, Reading: Another Explanation).

The material provides a few examples of classroom interactions (e.g., dialogue boxes, vignettes, or video clips) that illustrate appropriate ways to respond to student questions or ideas, etc. Examples of desirable student-teacher dialogues are provided for discussions of the "bounceability" of balls (pp. 166-166at, Process and Procedure, part A) and the movement of food coloring in water (p. 203t, Process and Procedure, part A). Two sample student dialogues are provided for the development of scientific models of the particle model (pp. 232-233t, Students' Models). Some sense of other desirable student interactions may be gained from procedural directions and descriptions of student roles and social skills in cooperative group activities (e.g., pp. 192-194s, Investigation: Mystery Box).

Supporting all students (Some support is provided.)

The material generally avoids stereotypes or language that might be offensive to a particular group. For example, the text includes a diverse cultural mix of students and adults in photographs (e.g., pp. 28s, 82-83s, 183-184s) and illustrations of diverse cartoon animal characters that routinely share their thinking in figures throughout the material (e.g., pp. 170-171s, 182s, 222s). The cartoon characters are representative of the four different learning styles of students and particular scientists (Europeans only). In some ways, however, the text may contribute to stereotypes and language that might be offensive. Scientists are often shown in stark black and white drawings that students may find odd or unreal (e.g., p. 234s). The text gives some historical reviews of scientific thinking that represent primitive thinking of Asian groups and current, sophisticated thinking of European groups, with emphasis on male scientists (pp. 185-188s, Reading: Elements of Explanations; 195-196s, Reading: Another Explanation). Most cooperative group skills appear inoffensive, but one, "Look at the person speaking to you," is a cultural practice and therefore may be uncomfortable for some students (p. 219s, Working Cooperatively).

The material provides some illustrations of the contributions of women and minorities to science and as role models. The illustrations sometimes occur in the main text (e.g., pp. 168s, 186-187s). They are also presented in sidebars that are interesting and informative, but may not be seen by students as central to the material (e.g., p. 166s, Sidelight on Technology). Children doing science in the video materials as well as cartoon characters of European scientists in the text are intended as role models for students. It is unclear, however, if students will relate to the cartoon animal figures, and their dialogues may appear extraneous to the main content of the text (e.g., p. 212s).

The material suggests multiple formats for students to express their ideas during instruction, including individual investigations and notebook writing (e.g., pp. 201-205s, Investigation: How Well Does the Particle Model Work?), cooperative group activities and lab investigations (e.g., pp. 183-185s, Investigation: Strange Phenomena, Part B-Puddle Mystery), and whole class discussion and drawing (e.g., p. 207bt, item 6). Introductory teacher's notes suggest using a wide variety of classroom activities for assessment, including in-class discussion, notebook entries, portfolios, and evaluate activities (Teacher's Resource Book, p. 33). However, the material does not usually provide a variety of alternatives for the same task in either instruction or assessment.

The material does not routinely include specific suggestions about how teachers can modify activities for students with special needs. However, the Teacher's Edition and Teacher's Resource Book provide some additional activities and resources for students. Within each chapter, the Teacher's Edition provides Further Opportunities for Learning, in which students may further study a related interest (e.g., p. 210t), sometimes using chapter and unit resources including websites (e.g., p. 179bt) and educational technology resources (software, CD-ROMs, videos, and laser discs [e.g., pp. 161b-161dt]). The Teacher's Resource Book includes a few extension activities similar in complexity to those in the student text (e.g., pp. 183-184).

The material provides a few strategies to validate students' relevant personal and social experiences with scientific ideas. A few text sections include a brief reference to a specific, personal experience students may have had that relates to the presented scientific concepts (e.g., p. 164s, Investigation: Bounce That Ball). In addition, a few tasks ask students about particular personal experiences they may have had or suggest specific experiences they could have. For example, after reading about the properties of translucence and hardness, students are asked to identify products in their homes with those properties (pp. 170-171s, Stop & Think, items 6, 9). However, the material rarely encourages students to contribute relevant experiences of their own choice to the science classroom, and sometimes it does not adequately link the specified personal experiences to the scientific ideas being studied (e.g., p. 171s, Stop & Think, items 11-12). Overall, support is brief and localized.


Diversity and Limits describes its use of the five E's instructional model as follows: "Each chapter goes through a cycle of activities, and each activity exemplifies one of the "E" words. First the students are engaged by an event or question related to the concept that the teacher plans to introduce. Then the students participate in one or more activities to explore the concept. This exploration provides students with a common set of experiences from which they can initiate the development of their understanding of the concept. In the explain phase, the teacher clarifies the concept and defines relevant vocabulary terms. Next, the students elaborate and build on their understanding of the concept by applying it to new situations. Finally, the students complete an activity that will help them and the teacher evaluate their understanding of the concept" (level B, p. xvii).