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Middle Grades Science Textbooks: A Benchmarks-Based Evaluation

Science Interactions. Glencoe/McGraw-Hill, 1998
Earth Science Life Science Physical Science

About this Evaluation Report
Content Analysis
Instructional Analysis

[Explanation] This section examines whether the curriculum material's content aligns with the specific key ideas that have been selected for use in the analysis.
[Explanation] This section examines whether the curriculum material develops an evidence-based argument in support of the key ideas, including whether the case presented is valid, comprehensible, and convincing.
[Explanation] This section examines whether the curriculum material makes connections (1) among the key ideas, (2) between the key ideas and their prerequisites, and (3) between the key ideas and other, related ideas.
[Explanation] This section notes whether the curriculum material presents any information that is more advanced than the set of key ideas, looking particularly at whether the “beyond literacy” information interrupts the presentation of the grade-appropriate information.
[Explanation] This section notes whether the curriculum material presents any information that contains errors, misleading statements, or statements that may reinforce commonly held student misconceptions.


Idea a: The surface of the Earth is changing continually.
There is a content match. General statements about this idea are found in all three course levels. For example, a summarizing paragraph at the end of chapter 15 explains that “wind, like gravity, running water and glaciers, shapes the land as it erodes. But the new landforms created by these agents of erosion are themselves being eroded. Erosion and deposition are part of a cycle of change that constantly shapes and reshapes the land around you” (course 1, p. 496s). Later in course 1, the introductory paragraph of Chapter 18: Earthquakes and Volcanoes states that “Change is always taking place on Earth” and briefly mentions that some changes are slow while others are sudden (course 1, p. 572s). In course 2, Chapter 12: The Ocean Floor and Shore Zones, the text states that “Shore Zones constantly change” (course 2, p. 362s). Lastly, a unit introduction in course 3 begins with a more general reference to change on the surface of the Earth by explaining that “our world—and the life on it—slowly it continues to do to this day” (course 3, p. 402s).

A few student questions address this key Earth science idea. Some only imply continual change to the surface of the Earth, such as, “Why are the Rocky Mountains in the west higher with sharper peaks than the more rounded Appalachian Mountains in the east?” (course 1, p. 28s), while others are more explicit, such as, “Why are dunes constantly changing?” (course 1, p. 496s). Very few student activities focus on the idea of continual change to the surface of the Earth. A teacher’s note (Extension) suggests that students draw maps to predict where landforms will occur in the future based on their knowledge of plate tectonics (course 3, p. 495t), while another asks students to predict the location of beach front property in 200 million years (course 3, p. 495t).

Idea b: Several processes contribute to changing the Earth’s surface.

There is a content match. Many Earth-shaping processes are presented and discussed throughout these three textbooks, but most of the content is found in course 1. The processes of erosion, such as gravity, running water, glaciers, wind, and volcanoes are presented in four chapters in course 1 (course 1, pp. 24–25s, 450–453s, 472–503s, 576–581s). Two chapters in course 2 focus on how volcanoes and shoreline erosion shape the Earth (course 2, pp. 52–81s, 362–365s) and one chapter in course 3 focuses on the changes associated with tectonic processes (course 3, pp. 468–501s).

In a few places, students are asked about several processes occurring at the same place, such as why both volcanoes and glaciers occur in Iceland (course 3, p. 494s). In another instance, two Earth-shaping processes are contrasted specifically, with the characteristics of valleys eroded by glaciers being compared to the characteristics of valleys eroded by streams (course 1, p. 492s). Unfortunately these nice qualities (i.e., having students compare different Earth changing processes and having students consider more than one process affecting an area at once) are not common characteristics of this textbook series.

Idea c: The processes that shape the Earth today are similar to the processes that shaped the Earth in the past.

There is not a content match.

Idea d: Some of the processes are abrupt, such as earthquakes and volcanic eruptions, while some are slow, such as the movement of continents and erosion.

There is a content match. In course 1, Chapter 15: Shaping the Land, has a text section that contrasts fast and slow types of erosion (course 1, p. 475s). In the same course, the introduction to chapter 18, explains that “some changes, such as the carving of a canyon by a river, take place so slowly that you may not notice the change in your lifetime. Other changes, however, are sudden and dramatic, catching everyone’s attention” (course 1, 572s). In course 2, faults are described as gradual or sudden movements of rocks (course 2, p. 52s). In the same course, chapter 12 discusses gradual versus rapid shoreline changes, such as how hurricanes leave obvious changes in shorelines that happen in a day (course 2, p. 384s). A reference to a rapid change on the surface of the Earth is found in course 3; diagrams of the eruption of Mount Saint Helen’s shows a fast change (course 3, pp. 496–497s).

Idea e: Slow but continuous processes can, over very long times, cause significant changes on the Earth’s surface.

There is not a content match. Although slow rates of change are mentioned a few times in the student text, there is no explanation that slow or small changes can over long time frames lead to significant changes on the surface of the Earth. For instance, in course 1, the text mentions that older mountains have eroded longer then younger mountains and are thus lower and more rounded (course 1, p. 24–25s). The accompanying photographs show the different appearances of mountains of different ages. Yet there is no discussion of how the older mountains have eroded slowly over a long period of time. Furthermore, the text does not explain the terms “older” and “younger” as ages of mountains. In course 3, diagrams show the locations of continents over millions of years, but do not mention how slowly the continents are moving over that period (course 3, p. 474s). Two activities ask students to calculate the rate of motion of plates, continents, or rocks as a result of plate tectonics (course 3, pp. 482–483s, 485t). However, there is no clear explanation that small rates of change can result in major changes to the land features of the Earth.

Idea f: Matching coastlines and similarities in rocks and fossils suggest that today’s continents are separated parts of what was a single vast continent long ago.

There is a content match. In course 3, Chapter 15: Moving Continents explains that “Wegener thought that the fit of the continents wasn’t a coincidence. He hypothesized that all the continents were once joined as one large supercontinent called Pangaea....” (course 3, p. 470s). The text briefly presents the fossil and glacial evidence for Pangaea as well as clues gathered from rock layers (course 3, pp. 470–475s). There are several questions that focus on this idea (see pp. 471t, 473s, 475s) and an activity in which students reconstruct Pangaea from the location of mountains, past glaciers, and fossils (course 3, pp. 472–473s).

Idea g: The solid crust of the Earth consists of separate plates that move very slowly, pressing against and sliding past one another in some places, pulling apart in other places.

There is a content match. This idea is mainly addressed in course 3. Specifically, the text explains that “The theory of plate tectonics suggests that the Earth’s crust and upper mantle are broken into sections called plates that move” (course 3, p. 484s). The three types of plate boundaries, namely, divergent, convergent, and transform boundaries, are discussed and illustrated (course 3, pp. 485–487s). Also several questions focus on this idea, such as “compare and contrast the types of movement that occur at divergent, convergent, and transform boundaries” (course 3, p. 490s).

This idea is also mentioned in course 2. In chapter 2, a sidebar feature in the student text briefly explains how earthquakes, volcanoes, and plate boundaries are related (course 2, pp. 68–69s). Plates are also mentioned in a diagram of ocean floor features (course 2, pp. 378–379s). Unfortunately this discussion of plate tectonics is not likely to be understandable to students. In course 2, the idea of plate tectonics is used as an explanation for other geologic events (such as earthquakes and volcanoes) and features (such as rift zones and ocean trenches), but students are not introduced to the subject of plate tectonics until they get to course 3 of this series.

Idea h: Landforms and major geologic events, such as earthquakes, volcanic eruptions, and mountain building, result from these plate motions.

There is a content match. Mostly, this idea is presented in course 3 of this series. This idea is addressed in text, representations (diagrams, etc.), and student questions. For example, diagrams show how the landforms (such as mid-ocean ridges, mountains, and rift valleys) are related to plate boundaries (course 3, pp. 478s, 485s, 486–487s, 489s). Questions such as, “Both Japan and California are prone to earthquakes. Explain this fact using plate tectonics” (course 3, p. 495s), focus on this idea.

Building a Case

Science Interactions asserts most of these key Earth science ideas in text, and provides students with activities to verify or exemplify them. However, an evidence-based case is presented for the idea that matching coastlines and similarities in rocks and fossils suggest that today’s continents are separated parts of what was a single vast continent long ago (Idea f). Students read about the evidence for this idea and how Wegener used it as a basis for proposing his hypothesis for continental drift. First, the text explains that two types of fossils were found on now far-spread continents and asks, “What could explain how these organisms got from one continent to another? And, how could Glossopteris live in climates as different as tropical Africa and polar Antarctica?” (course 3, p. 471s). Then glacial evidence (p. 471s) and matching rock layers (p. 475s) are presented. However, students may have difficulty appreciating these pieces of evidence. The formation of rock layers and fossils are presented in course 2 (chapter 11, pp. 343–349s, pp. 350–351s) and how glaciers carve distinct features are presented in course 1 (chapter 15, pp. 488–492s), but these earlier discussions are not mentioned. More importantly the text fails to point out that it is very unlikely for organisms to develop in exactly the same way in separate environments. Without this argument, the fossil evidence may not be convincing.

Furthermore, students are not involved in considering this evidence. One activity has students make cutouts of the continents and arrange them in as many ways as they can. Then students add symbols to the cutouts representing different pieces of evidence (mountain ranges, glacier features and fossils) and try to arrange them again (course 3, pp. 472–473s). Mountain ranges as evidence for Pangaea are not discussed in the text and might be confusing to students. Follow-up questions for this activity focus on how many ways the landmasses fit together, not the evidence itself.


Science Interactions distributes these key Earth science topics over seven chapters throughout its three-course series. Unfortunately, neither the logic for the sequence nor the distribution of these experiences is conveyed to students or teachers. For instance, the discussion of processes that shape the land (course 1, chapter 15) does not mention the types of landforms discussed earlier (course 1, chapter 1). In another instance, the theory of plate tectonics is developed in course 3, yet courses 1 and 2 mention it in reference to volcano and earthquake locations (course 1, p. 579t; course 2, pp. 68–69s). Using a technical term such as plate tectonics before it has been introduced and defined is likely to be confusing for students. Furthermore, each of the three courses includes sections on earthquakes and volcanoes, none of which are linked to each other.

Some activities (that appear in features such as Theme Connections, Across the Curriculum, Life Science Connection, Technology Connection, and Science and Society) are not well integrated into the chapter and break the flow of ideas. For instance, students are to report on giant tubeworms that live by deep undersea vents in the mid-ocean ridges (course 3, p. 478s); research myths, legends, and folktales about earthquakes (course 2, p. 55t); discuss the cave paintings in Altimira, Spain and Lascaux, France (course 1, p. 491t); and research the ruins of Pompeii (course, 1, p. 586t). These connections are not well linked to the specific key Earth science ideas.

Beyond Literacy

Science Interactions includes only a few topics that are beyond science literacy, such as types of magmas (course 2, p. 69s), the layers of the Earth (course 3, p. 476s), and the magnetic data used as evidence for seafloor spreading (course 3, pp. 479–483s). However, many of the chapters analyzed are cluttered with needless detail that may obscure the key Earth science ideas. For instance, some activities and readings focus on peripheral topics such as making a seismograph (course 1, pp. 590–591s), earthquake-resistant buildings (course 1, p. 593s), locating the epicenter of an earthquake (course 2, p. 65s), none of which focus on how earthquakes change the surface of the Earth. In another example, although the student text discusses how glaciers can change the surface of the Earth, the teaching transparencies focus on labeling the many depositional and erosional features of glaciers, such as eskers and moraines (course 1, p. 472c).


The evaluation teams developed a summary assessment of the most common kinds of errors found in each of the three subject areas—physical science, Earth science, and life science. In this context, “errors” is taken to mean not only outright inaccuracies, but also those instances in which the material is very likely to lead to or support student misconceptions. Overall, inducement to misconstrue is the most serious problem of accuracy in the evaluated materials.

The evaluation teams’ collective findings, presented below, should be taken as having general applicability to all of the evaluated materials, not complete and specific applicability in toto to any one of them.

Identified errors occur most frequently in drawings and other diagrams. They take the form of representations that are likely to either give rise to or reinforce misconceptions commonly held by students. Following are Earth science examples of the kinds of misleading illustrative materials of most concern to the evaluation teams:

  • Maps that do not show the accurate locations of earthquakes and volcanoes will prevent students from understanding the relationship between these events and plate boundaries. Likewise, diagrams and maps that do not include legends, and photographs that do not explain the size and scale of the object seen, are difficult for students to understand.

  • Diagrams that (a) depict plates moving away from one another, thus exposing the mantle, (b) show the mantle very close to the surface of the Earth, or (c) show plates as being a layer under the crust inaccurately represent the structure of the Earth and the motion of plates.

  • Diagrams that show the melting of subducted plates are incorrect. Subducting plates are known to cause melting in the mantle, and thus nearby volcanic activity, but the plates do not melt.