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Middle Grades Science Textbooks: A Benchmarks-Based Evaluation

SciencePlus: Technology and Society. Holt, Rinehart & Winston, 1997
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)

Each unit in SciencePlus begins with a two-page photograph accompanied by text and questions. In grade eight, however, these components do not provide a purpose for Unit 2: Particles as a whole or for the four chapters within the unit. The photograph shows a DNA molecule as seen through a scanning tunneling microscope, and the text and questions focus on how the microscope works and why studying the structure of a DNA molecule is useful (Level Blue, pp. 76–77st). Nothing explains how the microscope or DNA molecule is relevant to the purpose of a unit about the particulate nature of matter.

Another standard component, called Unit Focus, is intended to provide “interactive suggestions for introducing students to the unit” (p. T27). However the Unit Focus for this particular unit (unit 2) suggests that teachers use a discussion of a classroom object such as a window to introduce the concept of particles to students:

Point to a window and ask: From what kind of matter is the window made? (The window is made from glass) From what is the glass made? (Silica) From what is silica made? (Sand that is weathered quartz, which is made of molecules of SiO2) Continue asking similar questions until students either identify particles, atoms, or molecules or can no longer respond. Point out that in this unit, students will examine evidence that matter is made of particles. [p. 76t]

As presented, this purpose is not likely to be comprehensible, interesting, or motivating to students who have not studied particles before and do not know what evidence is (see Endnotes, note 4). Also, this purpose is not entirely consistent with the unit’s chapters, which, in addition to providing evidence that matter is made of particles, address how temperature affects matter and the structure of the atom.

The first lesson in unit 2 (Chapter 4: More Than Observing, Lesson 1: A Search for Explanations) presents an additional purpose for the unit that follows. After students read about an imaginary trip from another galaxy to the Earth during which smaller and smaller objects are detected, the text states:

What is the limit for detecting smaller and smaller bits of matter? Is there no limit to the size of objects that can be detected? The answers to these questions are important steps in the search for explanations about why matter behaves the way it does. This unit will lead you on a search for these explanations. [p. 79s]

Although this purpose is more likely to be understandable and interesting to middle school students, they are not asked to think about the purpose, nor does the unit return to this stated purpose.

Chapter introductions are somewhat different. Chapters begin with a one-page collage of photographs, pictures, diagrams, and questions. No purpose is presented other than the implication that the chapters will help students to answer the questions.

Conveying lesson/activity purpose (Rating = Fair)

SciencePlus conveys to students (or asks teachers to convey) a purpose for most of its lessons, and the purpose is likely to be comprehensible to them (e.g., pp. 88s, 88t [Getting Started], 99t [Getting Started]). A purpose is given for some of the explorations (e.g., pp. 88s, [Exploration 1], 103s [Explorations 5 and 6]), but not for others (e.g., pp. 99s [Exploration 2], 100s [Exploration 3]). Where they are given, the purposes do not engage students consistently in thinking about the explorations (why they should do them, what they will learn from them, or how they are connected to the purpose of the unit) or in thinking about what they have learned so far and what they need to learn and do next.

Justifying lesson/activity sequence (Rating = Fair)

SciencePlus does not provide a clear rationale for a logical or strategic sequence of the eighth-grade readings and activities that are given in Unit 2: Particles. Unit Compression (Level Blue, p. 75D) attempts to outline such a rationale, but it is not clear whether, or how, the progression outlined corresponds to the unit’s chapters and lessons. One can infer readily a reasonable sequence only for the unit’s chapters 4 and 5. Chapter 4: More Than Observing introduces concepts such as observation, inference, and modeling. Chapter 5: A Case for Particles starts building a case for the existence of particles (using the concepts of observation, inference, and model introduced in chapter 4); explores the size of particles; and extends the particle model of matter to include the ideas that particles of matter are in constant motion and that heating causes particles in a substance to move faster and farther apart. Chapter 6: Testing the Particle Model explores further how temperature affects the movement of particles; describes changes of state (primarily at a macroscopic level); introduces the concepts of exothermic and endothermic change; and explains, using the particle model of matter, how different materials with the same volume may have a different mass. Chapter 6 focuses excessively on macroscopic renditions of heating, cooling, melting, and evaporating, with very limited discussion of these processes at the microscopic level. It is not made clear that “Testing the Particle Model” is the focus of the chapter, making the lessons in this chapter appear more like a collection, rather than a well-sequenced series, of activities. Finally, Chapter 7: The World of Atoms describes the structure of atoms. It appears as an add-on, rather than the culminating chapter of a unit whose purpose is to provide evidence that matter is made of particles.

II. Taking Account of Student Ideas

Attending to prerequisite knowledge and skills (Rating = Poor)

SciencePlus addresses some prerequisites before the key ideas are introduced. For example, Chapter 11: Meet Matter addresses what is matter (although it does not discuss what is not matter) and mentions that air is matter; then the chapter’s lessons 1 (About Matter) and 2 (Matter’s Useful Properties) give students an opportunity to observe the characteristics of different states of matter and transitions between them. In grade eight (Level Blue), Unit 2: Particles enables students to have experiences with the concepts of observation, inference, and modeling before these concepts are used to build a case for the particle model of matter.

SciencePlus does not alert teachers to specific prerequisite ideas, nor does it point explicitly to the earlier chapters in which prerequisites are addressed. The material rarely makes specific connections between ideas and their prerequisites. For example, the discussion of what is matter is not an integral part of the presentation of the key idea that all matter is made of particles (Idea a); it precedes it, but it is not connected to it adequately. In addition, the discussion of changes of state at a microscopic level in grade eight’s Unit 2: Particles, is not connected to the earlier experiences with changes of state in grade six’s Chapter 11: Meet Matter.

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

Each chapter in SciencePlus begins with a section called Prior Knowledge and Misconceptions that encourages teachers to identify “the kind of information—and misinformation—[students] bring to this chapter” (e.g., Level Blue, p. 78t). However, it does not inform teachers about the extensive research that has been conducted regarding students’ understandings of topics like the structure of matter and the kinetic molecular theory. For example, research on student understanding of the structure of matter has revealed 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, Eichinger, Anderson, Berkheimer, & Blakeslee, 1993). Research also has revealed that students are often confused about the observable properties of substances versus the properties of molecules themselves. For example, students may think that molecules themselves become hot or cold, or that molecules themselves expand, causing substances to expand (Johnston & Driver, 1989; Lee et al., 1993). Teachers are not alerted to these commonly held student ideas. Only once does a suggested response to a ScienceLog question in the teacher’s notes mention that “[s]ome students may have the mistaken notion that there must be something in between the particles, probably more particles. Point out that this is incorrect” (Level Blue, p. 106t).

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

Several questions throughout the chapters may provide teachers with some help in identifying their students’ ideas. Such questions are found in components such as ScienceLog, and Prior Knowledge and Misconceptions, as well as questions interspersed in both the student and teacher editions. However, the sets of questions are insufficient to elicit the various student preconceptions that have been identified in research studies on the key ideas. There are enough questions that will help to elicit students’ ideas about the particulate nature of matter, but hardly any of the questions will help to bring out students’ problems with the intrinsic motion of particles or their tendency to attribute macroscopic properties to particles. ScienceLog questions sometimes express ideas in ways that are not likely to be meaningful to students who have not studied the topic and are not familiar with the scientific vocabulary. For example, at the beginning of a chapter that is meant to introduce the particle model of matter, the ScienceLog contains this question: “If you could see individual air particles, what might they look like?” (Level Blue, p. 78s). Despite these weaknesses, it should be noted that SciencePlus (unlike other middle grades textbooks) makes an explicit effort to help teachers identify their students’ ideas about the structure of matter.

Addressing commonly held ideas (Rating = Poor)

According to a suggested response to a ScienceLog question, “Some students may have the mistaken notion that there must be something in between the particles, probably more particles. Point out that this is incorrect” (Level Blue, p. 106t). This is the only instance in which a specific misconception is addressed directly in the materials, although merely telling students that their idea is incorrect is not likely to help most of them. None of the numerous, widely held ideas that relate to the kinetic molecular theory are addressed explicitly, nor are there any activities that would help students with their difficulties. Although teachers are given some help in identifying their own students’ ideas, they are not offered specific guidance on how to make use of the information.

III. Engaging Students with Relevant Phenomena

Providing variety of phenomena (Rating = Satisfactory)

Several phenomena are provided for four key ideas (Ideas a, c, d, f). For example, the compressibility of gases (Level Blue, p. 103s) is used to support the idea that matter is made of particles (Idea a). Phenomena such as diffusion in liquids (for example, food coloring diffusing in water [Level Blue, p. 104s]) and in gases (for example, perfume diffusing in the air [Level Blue, p. 103s]), as well as Brownian motion (Level Blue, p. 124s), are connected to the idea that particles move (Idea c) (see Endnotes, note 5). Increased rates of diffusion with increased temperatures (for example, the diffusion of food coloring in hot water [Level Blue, p. 103s]) and the thermal expansion of liquids (for example, liquid in a thermometer [Level Blue, pp. 108–109s]) and gases (for example, air in a balloon stretched over the mouth of a bottle when the bottle is heated [Level Blue, p. 104s]) are explained in terms of the idea that increased temperature means increased movement of the particles (Idea d). And, for particulate explanations of changes of state (Idea f), phenomena such as evaporating alcohol when it is heated (Level Blue, p. 117s), and wax near the flame of a burning candle melting, then solidifying after the candle has been blown out (Level Blue, p. 104s), are provided. SciencePlus contains very few phenomena related to the different arrangement, motion, and interaction of particles in the three states of matter (Idea e), and hardly any phenomena that illustrate the small size of particles (Idea b).

Sometimes the links that are made between phenomena and key physical science ideas are not clear or even valid. For example, students dilute a solution of food coloring repeatedly until they see the color no longer. It is not clear why the fact that “the food coloring spreads throughout the water and can be divided into smaller and smaller quantities” (Level Blue, p. 89t) supports the particulate nature of matter, as the text claims. Phenomena in which the volume of the solution of water mixed with another substance (e.g., alcohol) is smaller than the separate volumes of water and the solute are used frequently to support the idea that matter is made up of particles. The material claims that the volume of the solution is smaller because particles of the solute fill the spaces between the water molecules. But water is a very small molecule and most solutes are substantially larger. In the liquid state, water molecules are not spaced out nearly enough for alcohol molecules, for example, to fit in between them.

Providing vivid experiences (Rating = Satisfactory)

Several of the phenomena that support the key physical science ideas are presented to students in hands-on activities (see, for example, the nine examples discussed in the previous criterion). However, there are no vicarious experiences for some of the phenomena that students do not experience firsthand. For example, a phenomenon related to Brownian motion in an assignment is described briefly: “If you could trap a little smoke inside a transparent box and put it under a microscope, you would see the particles of smoke moving in a haphazard pattern” (Level Blue, p. 124s). This description is too short to give middle grades students a vicarious sense of the phenomenon. In grade six, Unit 4: Investigating Matter, Chapter 13: More About Matter asks students to link general properties of solids, liquids, and gases (such as, “Liquids can flow, but solids are rigid,” or “Gases do not have an interface with air; solids and liquids do” [Level Green, p. 238s]) to the particle model of matter. Specific phenomena to illustrate generalizations about these properties (such as that solids are rigid) are not included, nor are there examples of solids, liquids, and gases in close proximity.

IV. Developing and Using Scientific Ideas

Introducing terms meaningfully (Rating = Satisfactory)

Typically, terms are presented in connection with a relevant experience (for example, see the introduction of the term “matter” in grade six [Level Green], pp. 200–204s). Frequently, but not always, the technical vocabulary is restricted to the terms needed to discuss the important ideas. For example, in describing the properties of matter and the kinetic molecular theory, terms such as “endothermic” and “exothermic” (Level Blue, p. 115s), and “interface,” “liquefaction,” “rigidity,” and “vaporization” (Level Green, pp. 230–233s), are introduced even though they are not necessary for understanding the key ideas. The term “particle” is used carelessly to refer to anything from sand grains and blood cells to molecules and atoms, from subatomic particles like electrons, protons, and quarks to a particle theory of light. The text gives no indication about the order of magnitude of the phenomena being discussed.

Representing ideas effectively (Rating = Poor)

Overall, the material includes only a small number of relevant representations. For example, the text contains very few drawings showing the arrangement and motion of molecules in gases, liquids, and solids (Idea e). Most of the representations are likely to be misleading or confusing to students. For example, an illustration shows molecules in a gas, liquid, and solid, but the graphic indicates the motion of the molecules only in the gas and liquid (Level Blue, p. 105s). This representation may reinforce the erroneous notion that the molecules in solids are still. The molecules in the three states appear in different colors, which may reinforce the erroneous idea that the molecules themselves are different, not their arrangement and motion.

Another illustration shows little creatures that represent particles of solids (the creatures sit at home), liquids (the creatures run and slide), and gases (the creatures run and some of them try to exit their space) (Level Blue, p. 106s). The creatures that represent the molecules in the three states are the same distance from one another and appear in different colors. This depiction may lead to the incorrect notion that differences between the solid, liquid, and gaseous states of a material are due to differences in the molecules themselves and not to the different arrangement and motion of the molecules, as well as the incorrect notion that the distances between the molecules in solids, liquids, and gases are similar. Finally, the text accompanying the illustration describes the particles in gases as “particles with claustrophobia.” This phrase may lead students concluding that particles in gases fill out the space available to them because they are “claustrophobic,” rather than because of their constant random motion.

Demonstrating use of knowledge (Rating = Poor)

The material contains no demonstrations of using the key physical science ideas to explain phenomena or solve problems. Although the teacher’s notes frequently include explanations using the key ideas in response to questions posed in the student text, the responses are brief and are not likely to be helpful for modeling explanations for students. Moreover, these responses to questions are not labeled as an example of how the key ideas can be used to explain phenomena or to demonstrate the use of knowledge. Since they appear as answers in the teacher’s notes, teachers may use them only to correct student papers, so students may never hear or read the correct answers.

Providing practice (Rating = Satisfactory)

Overall, SciencePlus provides a satisfactory number and variety of questions and tasks (including novel questions and tasks) for students to practice using the key ideas. There are several questions for students to use to practice the idea that matter is made up of particles (Idea a) (for example, Level Blue, pp. 91t, 105s, 124s, 139s), and some questions for them to use to practice the different arrangement and motion of particles of solids, liquids, and gases (Idea e) (for example, Level Blue, pp. 105s, 106s, 138s), as well as particulate explanations of changes of state (Idea f) (for example, pp. 105s, 139s). Fewer questions are related to the small size of particles (Idea b) and their perpetual motion (Idea c). Opportunities for practice appear in several sections, such as Closure, Reteaching, Extension, and the Challenge Your Thinking questions that appear at the end of each chapter. Each unit concludes with an interesting set of questions and tasks that could provide additional opportunities for practice (namely, Unit Review—Making Connections), although the introductory teacher’s notes present these components primarily as an assessment tool (p. T24).

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

Encouraging students to explain their ideas (Rating = Satisfactory)

Students are asked to express their ideas routinely in grade six (Level Green), Unit 4: Investigating Matter (e.g., p. 237t [Guided Practice]; p. 238s [Pause for Thought]; p. 239t [Guided Practice]; p. 240t [Independent Practice]; p. 240t [Portfolio]; p. 241s [Be a Writer]), and frequently in grade eight (Level Blue), Unit 2: Particles (e.g., p. 83s [Using Models]; p. 85s [This Model Is All Wet]; p. 90s [Drawing Conclusions]). They are asked many times to represent their ideas (e.g., Level Green, p. 240t [Portfolio]; p. 241s [Be a Writer]) or to justify them (e.g., Level Blue, p. 83s [Using Models]; p. 85s [This Model Is All Wet]; p. 90s [Drawing Conclusions]), but rarely to clarify them. For the most part, they are asked to express their ideas in large group discussions, although opportunities are provided for journal writing and small group work, too, ensuring that all students have an opportunity to express their ideas. Teachers are not instructed explicitly to provide feedback to students, nor are suggestions made about how feedback could be given that helps students to develop their ideas further.

Guiding student interpretation and reasoning (Rating = Fair)

Most of the Exploration segments are followed by questions intended to help students think about the exploration. Such questions often ask students to relate their observations to the particle model of matter, but they rarely help students to make connections between their own ideas and what they observe. Most importantly, questions are rarely structured so that they lead students gradually from observations to inferences. Rather, students are asked to make huge leaps from observations to inferences (e.g., Level Blue, Exploration 1, pp. 88–89s; Explorations 2 and 3, pp. 99–100s; Exploration 5, p. 103s).

Teachers are not advised about what to do if students do not respond in the way that they are supposed to, nor are they urged to facilitate discussion among students about different interpretations of the same observation. In some cases, the teacher’s notes do not even provide the correct interpretation of the observation(s) made. For example, in grade eight, students are to observe that a syringe filled with air is easy to compress, whereas a syringe filled with water is hard to compress; then they are asked to imagine what would happen if they tried to compress a syringe filled with a solid (Level Blue, p. 103s). From this setup, students are asked to infer what differences there are between the particles of a solid and those of a liquid or a gas. The expected inference (based on the teacher’s notes) is that the particles of a solid are locked in place, whereas the particles of liquids and gases can move about (p. 103t). This is not a valid inference. The differences in compressibility between solids, liquids, and gases do not give credence to the idea that the particles of solids are locked in place, while the particles of liquids and gases can move about. A more reasonable inference from the difference in compressibility between a liquid and a gas (which students are asked to make next) would be the difference in distance between particles. Even then, the argument requires that students make too big a leap. In addition, it is unreasonable to expect them to infer the spacing of particles from the observation of a single instance of the macroscopic behavior of substances.

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

Each chapter in SciencePlus begins with a ScienceLog that invites students to express what they know already about some of the questions that will be addressed in the chapter. Revisiting the ScienceLog at the end of the chapter gives students opportunities to reconsider and possibly revise their initial answers. However, they are not asked specifically to think about how their ideas changed, and the questions in the ScienceLog address only a small part of the key ideas. Moreover, students are not given explicit opportunities to monitor their understanding as they progress through the chapter.

VI. Assessing Progress

Aligning assessment to goals (Rating = Very good)

For the end-of-instruction assessment, SciencePlus provides Chapter Assessment items, End-of-Unit Assessment items, and Activity Assessment items in a separate Test Generator: Test Item Listing booklet. In addition, the Challenge Your Thinking and Making Connections components in the student text are identified as end-of-chapter and end-of-unit assessment, respectively (Level Blue, pp. T24, T60). These components of Unit 2: Particles in grade eight (Level Blue) have been examined in terms of the first two assessment criteria. There is also an item bank that is not substantially different from the tests and, therefore, has not been examined.

SciencePlus includes many assessment tasks that align with the key physical science ideas. For the idea that all matter is made up of particles (Idea a), students are asked, “What evidence is there that matter is made up of particles?” (p. 138st, item 3), and they have to name three observations that support the particle model of matter (Unit 2, End-of-Unit Assessment, p. 68, item 7). Additional questions related to the particulate nature of matter require students to know other physical science ideas. For example, they are asked to explain why “many objects with the same volume have different masses” (p. 138st, question 9). Although they would need to understand the idea that all matter is made of particles to answer this question, they also would have to understand that “[e]qual volumes of different substances usually have different weights” (American Association for the Advancement of Science, 1993, p. 78). Similarly, students are asked to apply the particle model of matter to explain the following situation: “In five trials, 50 g of copper is allowed to react with oxygen to form copper oxide. Each time, the copper reacts with the same amount of oxygen” (Chapter 5 Assessment, p. 55, item 4). But this question involves the use of other ideas, such as the idea that “[s]ubstances react chemically in characteristic ways with other substances….” (National Research Council, 1996, p. 154).

Several items are provided to assess the idea that increased temperature means greater molecular motion (Idea d). Students are asked to explain “the effect of temperature changes on the particles making up matter” (p. 138st, question 7), hypothesize what might have been done to a balloon with an initial mass of 6.2 grams and volume of 2.3 liters to cause its volume to increase to 3.2 liters (p. 139st, item 3), describe the melting of stearic acid using the words “particles,” “change of state,” “temperature,” and “faster,” and explain why they “can smell apple pie just taken out of the oven but can’t smell apple pie just taken out of the refrigerator” (Chapter 6 Assessment, p. 58, items 1 and 3). They are told that “[a] microwave oven works by heating water molecules inside a substance” and then are required to explain why potatoes sometimes explode in the oven (Chapter 6 Assessment, p. 59, item 5). Lastly, students have to explain “why the mercury in a thermometer rises when the thermometer is placed in hot water” (Unit 2, End-of-Unit Assessment, p. 69, item 10).

The idea that there are differences in the arrangement and motion of particles in solids, liquids, and gases (Idea e) is assessed in five tasks: Students are required to design a model for water that represents what happens when liquid turns into ice and into steam (p. 85st), and to complete a table listing words that describe the motion of particles (such as wriggling and vibrating) by identifying the state of matter that corresponds to each word and by suggesting everyday events similar to the way in which particles move (for example, students wriggling in their seats) (p. 105st, question 1). They are shown an illustration of particles in a solid, liquid, and gas then and are asked to write a sentence to explain to a fifth-grader what is happening in each picture (p. 105st, question 2). They are shown another illustration representing particles in the three states and are asked to identify which particular characteristic of the particles is referred to in each illustration (p. 106st, question 3). Unfortunately, these last two questions include illustrations that can be severely misleading to students (for example, in the first illustration, the particles in a solid appear static). A better use of these illustrations would be to ask students to critique the illustrations based on what they know. At the end of the unit, students are asked to explain how the particle model explains the properties of solids, liquids, and gases (p. 138st, question 6) and also to explain observations based on an illustration of a boat in an environment of sea, sun, clouds, and icebergs using the particle model (Unit 2, End-of-Unit Assessment, p. 69, item 9).

Students’ ability to explain changes of state at the molecular level (Idea f) is assessed by the following items. Students explain the melting of stearic acid and complete the statement, a “substance that melts at 10°C has greater force of attraction among its molecules than a substance that melts at ___” (Chapter 6 Assessment, p. 58, items 1 and 2b). They provide molecular explanations for the turning of butter to liquid when heated and the disappearance of a puddle during the day, and identify and explain observations based on an illustration of a boat in an environment of sea, sun, clouds, and icebergs (Unit 2, End-of-Unit Assessment, p. 66, items 1a and 1c; p. 69, item 9).

However, a few key ideas are not adequately assessed. For example, the idea of molecular motion (Idea c) is assessed in two tasks: Students are to explain how the fragrant part of air fresheners gradually disappears (p. 139st, item 4), and how “[m]othballs can be smelled across the room from the clothes closet in which they are located” (Unit 2, End-of-Unit Assessment, p. 66, item 1b). However, these tasks may not require that students realize that molecules are perpetually in motion.

No questions require the idea that molecules are extremely small (Idea b). While students might use this idea in responding to the question below, they could also respond without using the idea: They are to imagine that they have been “shrunk to the size of a water molecule” and write a story that describes an adventure they have while they are this size using one thing they have learned about the particulate nature of matter (Unit 2, End-of-Unit Assessment, p. 71, item 12).

Testing for understanding (Rating = Satisfactory)

In the introduction to SciencePlus, the Teacher’s Guide states that “[t]he authors strongly discourage reliance on recall-based assessment strategies” (p. T58). Indeed, compared to other materials, SciencePlus hardly includes any questions based on memorization. Most items described above require application of the key ideas. However, the number of relevant application items is not adequate for some ideas. For example, the ideas of perpetual motion in liquids (part of Idea c) and of the small size of molecules (Idea b) are not applied.

Using assessment to inform instruction (Rating = Poor)

SciencePlus emphasizes that “[a]ssessment should be ongoing” (p. T58) and claims that the Assessment component at the end of each lesson should be used “to evaluate whether students have grasped the main concepts. If you find that your students need additional help, a reteaching strategy is provided” (p. T28). However, the Reteaching components precede the Assessment components and often focus on different ideas and skills. In most cases, neither the Reteaching nor the Assessment is aimed at the key physical science ideas. In other instances, the key idea is addressed, but the suggestion is not likely to be helpful for students having difficulty. For example, after students are introduced to the idea that matter is made up of tiny particles (Idea a), the Assessment component has them construct models of molecules and hang them on mobiles (Level Blue, p. 98t) and the teacher is advised to have other students identify the substances represented by the molecules. Students having difficulty with this key idea can successfully construct the required molecular models while still believing that molecules are in materials, as opposed to believing that molecules constitute materials. Furthermore, while some relevant questions are included, SciencePlus does not include suggestions for teachers about how to probe beyond students’ initial responses to better understand where they are in their learning, nor does it include specific suggestions about how they can use students’ responses to make decisions about instruction.

VII. Enhancing the Science Learning Environment

Providing teacher content support (Minimal to 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 Annotated Teacher’s Edition briefly summarize the student text at the beginning of each unit (e.g., Level Green, p. 197A, Unit Overview; Level Blue, p. 75A, Unit Overview), provide a few additional related facts throughout the chapters (e.g., Level Green, p. 243t, Did You Know…; Level Blue, p. 105t, Did You Know…), and give some elaboration of special features at the end of each unit (e.g., Level Blue, p. 141t, Background; Level Red, p. 210t, Background). Overall, the teacher content support is brief and highly localized.

The material provides some sufficiently detailed answers to questions in the student text for teachers to understand and interpret various student responses. While the material usually provides correct, well-developed answers to questions, little additional information is provided for teachers on how to field potential student questions or difficulties (e.g., Level Green, p. 230t, Answer to Solid or Liquid?; Level Green, p. 236t, Answers to Fifteen Hypotheses). In addition, some answers are brief and require further explanation (for example, “Accept all reasonable responses” [Level Green, p. 237t, Teaching Strategies]).

The material provides minimal support in recommending resources for improving the teacher’s understanding of key ideas. While the material presents lists of references (including books, films, videotapes, software, and other media with addresses for ordering) that could help teachers improve their understanding of key ideas (e.g., “Stwertka, Albert. The World of Atoms and Quarks. New York City, NY: Twenty-First Century Books, 1995” [Level Blue, p. 75A]), the lists lack annotations about what kinds of information the references provide or how they may be helpful.

Encouraging curiosity and questioning (Some support is provided.)

The material provides a few suggestions for how to encourage students’ questions but gives little support in guiding their search for answers. For example, a few tasks ask students to generate their own questions about the scientific ideas studied (e.g., Level Green, p. 316t, Prior Knowledge and Misconceptions).

The material provides many suggestions for how to respect and value students’ ideas. Introductory teacher’s notes about concept mapping respect and value students’ ideas by stating that “there is no single ‘correct’ concept map” (p. T39), but also give teachers some guidance about general characteristics of good maps. In addition, students and their ideas are highlighted throughout the text. For example, photographs and dialogue balloons present students discussing scientific ideas to be studied (e.g., Level Blue, p. 96s). Students are specifically referenced in some student tasks (e.g., Level Green, p. 231s, item 2). In addition, the material explicitly elicits and values students’ ideas in some text passages (e.g., Level Blue, p. 91s) and many tasks. For example, an introductory task for a chapter about particles asks students to speculate about the smallest particle that could be identified by breaking a rock into smaller and smaller pieces. Teacher’s notes respect and value students’ ideas by stating, “Assure students that there are no right or wrong answers to this exercise,” and suggesting that teachers use students’ work to identify their misconceptions and areas of interest in the topic (Level Blue, p. 87t, Prior Knowledge and Misconceptions).

The material provides a few 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 encourage students to pose such questions themselves. Specifically, the material includes a few tasks that ask students how they know something or to provide evidence in their responses (e.g., Level Green, p. 231st, At-Home Investigation, item 3; Level Blue, p. 90st, Drawing Conclusions).

The material provides many suggestions for how to avoid dogmatism. Introductory teacher’s notes provide suggestions for avoiding dogmatism through the use of guiding principles such as, “Anyone can learn science” and “Science is a natural endeavor” (p. T17). Introductory teacher’s notes also explain the STS (science, technology, and society) approach of the material that “teaches science from the context of the human experience and in so doing leads students to think of science as a social endeavor” and “emphasizes personal involvement in science” (p. T35). In accordance with the introductory guiding principles, the student text portrays the nature of science as a human activity in which students participate (e.g., Level Green, pp. 237–238s), and it describes changes over time in scientific thinking (e.g., Level Blue, pp. 127–135s). In addition, the material includes some text passages and special features illustrating the work of particular, practicing scientists (e.g., Level Blue, pp. 92–93s) and highlighting the contributions of specific cultural groups (e.g., Level Blue, p. 117t, Multicultural Extension).

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, some sense of desirable student interactions may be gained from student dialogues about the scientific ideas studied (e.g., Level Blue, p. 96s) and procedural directions and descriptions of student roles in cooperative group activities (e.g., Level Green, p. 234t, Cooperative Learning: Exploration 1; Level Blue, p. 97t, Cooperative Learning: Even More Models; pp. T41–T46, Cooperative Learning).

Supporting all students (Considerable support is provided.)

The material generally avoids stereotypes or language that might be offensive to a particular group. Introductory teacher’s notes state that the material actively attempts to refute stereotypes by portraying “science as a rewarding, quintessentially human undertaking” and by presenting scientists as “normal people, not aloof geniuses who talk in equations” (p. T17). For example, several photographs include a diverse cultural mix of students and adults (e.g., Level Green, pp. 234–235s; Level Red, pp. 164–165s; Level Blue, p. 88s). In addition, the material’s use of multiple writing genres, including traditional expository text and some narrative forms (e.g., Level Green, p. 241s), may support the language use of particular student groups.

The material provides some illustrations of the contributions of women and minorities to science and as role models. Most of the contributions of female and minority scientists, however, appear in a few special features at the end of each unit. For example, one Science in Action feature focuses on the work of Melissa Franklin, a female experimental physicist who studies some of the smallest particles of matter, quarks, and contributed to the discovery of the top quark using a large instrument called a particle accelerator (Level Green, p. 246st). In addition, Multicultural Extension teacher’s notes within chapters highlight specific cultural contributions related to chapter topics (e.g., Level Green, p. 243t). All of these sections highlighting cultural contributions are interesting and informative but may not be seen by students as central to the material because they are presented in sidebars and teacher notes.

The material suggests multiple formats for students to express their ideas during instruction, including individual ScienceLog writing (e.g., Level Blue, p. 87s, ScienceLog), cooperative group activities (e.g., Level Blue, p. 97st, Even More Models), laboratory investigations (e.g., Level Blue, pp. 88–90st, Exploration 1), whole class discussions (e.g., Level Green, p. 237t, Getting Started), essay questions (e.g., Level Green, p. 231st, item 3), concept mapping (e.g., Level Blue, p. 96s, item 1), creative writing (e.g., Level Green, p. 236t, Closure), role-playing (e.g., Level Green, p. 229t, Teaching Strategies), visual projects (e.g., Level Green, p. 236t, Extension), and oral presentations (Level Green, p. 241t, Extension). In addition, multiple formats are suggested for assessment, including individual ScienceLog revising (e.g., Level Green, p. 243st, ScienceLog), oral discussion (e.g., Level Green, p. 241t, Assessment), essay (e.g., Level Blue, p. 124st, item 1), performance (e.g., Level Blue, p. 102t, Assessment), portfolio (e.g., Level Blue, p. 91t, Portfolio), and visual projects (e.g., Level Blue, p. 98t, Assessment). In a few instances, the material also provides a variety of alternative formats for the same task (e.g., Level Blue, p. 91t, Assessment).

The material does not routinely include specific suggestions about how teachers can modify activities for students with special needs. However, the Annotated Teacher’s Edition and supplemental resources (including review, reinforcement, and enrichment work sheets and activities with transparencies) provide additional activities and resources for students and sometimes specify ability levels. The Annotated Teacher’s Edition includes a Meeting Individual Needs feature that provides activities for students related to chapter topics and specifically designated for gifted learners, second-language learners, and learners having difficulties (e.g., Level Green, p. 230t; Level Blue, p. 94t). For Spanish speakers, there are English/Spanish audiocassettes, which preview each unit in both languages. Also, in the Teacher’s Resource Binder and Teaching Resources there are Spanish unit summaries, work sheets, glossaries, and English and Spanish Home Connection letters, which introduce parents to each unit and provide related home activities for students to do with parents. However, the placement of supplemental resources in individual booklets separate from the main text may discourage their use, and the special needs codes within chapters may discourage teachers from using those activities with all students when appropriate.

The material provides many strategies to validate students’ relevant personal and social experiences with scientific ideas. Some text sections relate specific, personal experiences students may have had to the presented scientific concepts (e.g., Level Blue, p. 116s). In addition, some tasks ask students about particular, personal experiences they may have had or suggest specific experiences they could have. For example, following a classroom activity where students observe changes of state, a question asks them to identify three places in their own homes where condensation occurs. The task then asks students to “explain why the condensation occurred” (Level Green, p. 235s, Think About It, item 3). For a few tasks, however, the material does not adequately link the specified personal experiences to the scientific ideas being studied (e.g., Level Blue, p. 87t, Homework).



According to the teacher’s notes, “Students may infer that the particles of salt have filled in the spaces between water particles” (p. 238t) but do not point out that this statement is incorrect. In fact, the sodium and chlorine ions do not merely fit in between the water molecules. Rather, the ions disrupt the lattice of water molecules, causing the lattice to collapse. However, this explanation requires an understanding of the lattice structure of water, which goes beyond the level of sophistication recommended for eighth-grade students in Benchmarks for Science Literacy (American Association for the Advancement of Science, 1993) and National Science Education Standards (National Research Council, 1996).

2. The suggested response in the teacher’s notes—“Because the dissolved sugar particles occupy spaces between the water molecules, the volume of the solution will be less than that of the unmixed sugar and water” (Level Red, p. 155t)—is incorrect, as pointed out above in note 1. Water is a very small molecule and most solutes are substantially larger. In the liquid state, water molecules are not spaced out nearly enough for the sugar molecules to fit in between them.

3. Before students are asked to add a statement to the particle model of matter, they are asked to conclude what differences there are between the particles of a solid and those of a liquid or a gas. The suggested response in the teacher notes—“The particles of a gas can be compressed. The particles that make up a liquid cannot be noticeably compressed. A piece of chalk could not be compressed in the syringe. The particles of a solid are locked in place, while the particles of liquids and gases can move about” (p. 103t)—is not a valid inference from these observations.

4. The Unit Focus is accomplanied by a scanning tunneling microscope image that has a rather confusing caption about how the image was formed and its particulate interpretation. This is also unlikely to attract the interest of students because it is far removed from their experiential world (Level Blue, pp. 76-77s).

5. Diffusion is slow. Observations about food coloring mixing in water and mixing faster in warmer water, and about perfume diffusing, are primarily to convection.