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Middle Grades Science Textbooks: A Benchmarks-Based Evaluation

PRIME Science. Kendall/Hunt Publishing Company, 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. The beginning of Chapter 5: On the Rocks in level 1 states that “the surface of the Earth is constantly changing” (level 1, p. 110s). Likewise, in the Teacher’s Guide, a Key Point for the chapter states, “The surface of the Earth is changing, usually (but not always) at a very slow pace” (level 1, p. 327t). However, contrary to these initial statements, the continually changing nature of the Earth is not presented in this lesson (lesson 1, p. 327t). Although this lesson discusses repeating geologic events, specifically the eruptions of Mount Saint Helens and historic earthquakes (level 1, pp. 110–111s, 327–336t), it does not explain that the Earth’s surface is constantly changing. In the following lesson, the teacher is to begin a discussion of the rock cycle by asking if “the surface of the Earth is the same as it has always been…” (level 1, p. 338t). The Teacher’s Guide explains that students “will know from the previous lesson that it [the surface of the Earth] is not [the same].” Similarly, the Teacher’s Guide for Level B uses “Rocks and soil are constantly changing, but usually at a very slow rate” as a Key Point to be made in the chapter (p. 175t). In this lesson, however, the changing nature of rocks is not related to the idea that the surface of the Earth is also constantly changing.

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

There is a content match. Level 1 presents several ways in which the surface of the Earth changes, such as erosion, volcanism, how folded mountains form, gravel deposition, and plate tectonics. The photographs of the eruption of Mount Saint Helens attempt to show how the mountain looked before and after the eruption, thus showing the change to the surface of the Earth (level 1, p. 111s). However, the photograph after the eruption is too cloudy to see how the shape of the mountain changed as a result of the eruption. In another instance, a diagram shows that the town of Rye, England, which was once a seaport, is now 3 miles inland due to several centuries of gravel deposition. Unfortunately, none of the other examples show how the Earth changed as a result of a physiographic process.

In level B, students discuss a few ways in which rocks change, such as weathering, erosion, acid rain, and frost, but there is no generalization made regarding the idea that all of these processes contribute to the changing surface of the Earth. In fact, many of the processes in this chapter are studied by looking at buildings, gravestones, or other structures, without discussing how the processes affect land features on the surface of the Earth. One lesson in level B includes a student discussion of five photographs of landforms and asks, “[H]ow to you think each one was formed?” (level B, pp. 90–91s). And, the following activities focus on the water and rock cycle, not how these processes change the surface of the Earth.

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

There is a content match. This key idea is presented and explained in the Teacher’s Guide a few times, but it is seen only once in the student text, where it is not explained well. In level 1, this idea is addressed in an activity in lesson 2 called What Rocks Tell Us: Age, Past Climates, History (pp. 128–129s, 338–341t, 344–347t). In the Teacher’s Guide, the background information explains that “geologists believe the present is a ‘key’ to the past. What we see today gives us clues to what happened in the past” (level 1, p. 338t). The activity has students “use this idea together with their existing knowledge about the formation of rocks to solve a series of eight puzzles based on simple geological situations” (level 1, p. 338t). Students examine a collection of rocks and answer questions about the age of rocks, past climates, and history. However, nothing in this activity clarifies this key idea for the students. Later in the lesson, one of the Key Points in the Teacher’s Guide states that “geologists use theories of gradual change and similarity of processes over geological time to explain how rocks were formed and deformed” (level 1, p. 351t). This key idea is stated again in the Teacher’s Guide:
[U]niformitarianism, which is based on the idea that, ‘the present is the key to the past,’ was developed by Charles Lyell in the 1830’s. It assumes that laws of physics and chemistry that are in effect today also operated in the past. [level 1, p. 353t]

Unfortunately there is no instruction to the teacher to discuss this idea further with the students. This key idea is presented in the student text only once in a subtitle that simply states that "the present is the key to the past” (level 1, p. 117s). The only further explanation provide in the student text is that “we know that these ripples on the beach are caused by wave action” and “we assume that these ripples in sandstone rock were formed in a similar way” (level 1, p. 117s). In level B, a Key Point explains that “the processes that made land forms are still active today” (p. 199t). However, nothing in this lesson or chapter provides further explanation.

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. Slow and quick changes to the surface of the Earth are mentioned, but time frames for these processes are not discussed. The chapter 5 introduction explains that, “when left to nature, the face of the Earth usually takes millions of years to change. Of course, there are exceptions, such as sudden and sometimes frightening volcanic eruptions and earthquakes” (level 1, p. 109s). A statement in the Teacher’s Guide also addresses this idea, which explains that “erosion and deposition can occur over a relatively short period of time if the rocks are soft, or it can take millions of years for new land forms to be created” (level 1, p. 353t). In other places, slow changes are mentioned:
  • Although the processes that shape the Earth’s surface are slow, they have produced spectacular results, including the great continental land masses and the vast oceans of the world. [level 1, p. 109s]
  • As geologists began to learn more about how rivers and glaciers carry debris, and about how slowly landforms change, catastrophic theories gave way to those of gradualism. These theories, which claim the Earth changes gradually, gained popularity when people began to realize that rock are very, very old. [level 1, p. 116s]
  • It is now generally accepted that changes in Earth’s crust are gradual, and that the span of geological time is vast. [level 1, p. 353t]

However, these examples are not further explained, and no questions, tasks, or activities focus on this key idea.

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 or gradual changes to the surface of the Earth are mentioned in the student text and Teacher’s Guide (see discussion of Idea d), these explanations do not discuss how small, seemingly unnoticeable changes on the surface of the Earth can accumulate over long periods of time.

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. Level 1 includes an activity in which students role-play a symposium on the movement of continents (identified as “continental drift”). Students study work sheets (copied from the Teacher’s Guide) that contain data from different research groups, and then they debate evidence for and against continental drift. Some of the groups present early research involving glacial, fossil, and rock evidence (level 1, pp. 362t, 363t, 364t, 365t). Some of the research groups present counterevidence such as:
If America was once joined to Europe, the fossils should be the same. But you find that only 5% of the fossils in Ireland match those found in Newfoundland. You are worried that too much importance has been made of the Continental Drift Theory. [level 1, p. 364t]

At the end of the role-playing activity, students read about the real symposium on continental drift held in New York in 1926. However, the summary of the real symposium does not explain why certain pieces of evidence are more convincing than other pieces of evidence. Later, students are to use this key idea to answer a question at the end of the chapter in which they are to write a story about Wegener’s theory of continental drift (level 1, p. 127s, item 6).

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. In level 1, a Key Point states that “scientists now believe that the rigid plates move over the Earth’s surface” (p. 352t). A similar statement in the student text explains that
scientists now believe that the Earth’s outer surface is cracked like a giant eggshell. It is fractured into many huge slabs which, because of their rigidity, are called plates…. [P]lates are not anchored to the core of the planet, but drift about. [level 1, p. 118s]

Text and diagrams explain that plates can collide and slide past one another, but the idea that plates can move away from each other is less clear. A diagram shows a midocean ridge that is also labeled as ocean floor spreading. The accompanying text explains that “the terrain around [ocean ridges] bears marks of having been stretched, not compressed” (level 1, p. 119s). This statement does not make explicit the idea that the Earth’s plates are pulling away from each other. Also a work sheet from the Teacher’s Guide (to be copied for the students) discusses the San Andreas Fault and how two plates are moving past each other and moving in different directions (level 1, p. 376t).

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. In level 1, a Key Point states that “earthquakes, volcanoes, and mountain ranges occur where plates meet” (p. 352t). The relationship between mountains, earthquake and volcano locations, and plate boundaries is also explained in the student text:
[T]he map above shows the distribution of mountain ranges, earthquakes, and volcanoes. Their locations usually correspond to the boundaries between major plates, regions where the Earth’s crust is most active…. At the center of each individual plate, the crusts are relatively stable. But where the neighboring plates meet, plates rub and crash against each other so that earthquakes, volcanoes, and mountain ranges occur. [level 1, p. 118s]

On the next page, the Andes and Himalayan Mountains as well as the San Andreas Fault are given as examples of land features that were created as the result of moving plates (level 1, p. 119s). An activity at the end of the chapter asks students to locate six well-known volcanoes (such as Mount Fuji and Mount Etna) on the map and decide which occur where plates are colliding (level 1, p. 126s). Lastly, a sample assessment question asks “[w]hat land form would be made as the plates [in the diagram] move closer and the continents collide?” (level 1, p. 385t).

Building a Case

PRIME Science does not attempt to build a case for any of the key Earth science ideas. Even though some of the early evidence for continental drift is presented in a class activity, students are not told that such evidence constituted the data that led scientists to conclude that the continents were once joined. In the activity, students are to debate some of the early evidence for and against continental drift. Unfortunately, they are not given any further guidance or explanation as to why some data are more convincing than other data. Furthermore, some of the evidence that students are to use in the debate is beyond the Earth science knowledge discussed in the chapter and most likely beyond the knowledge of the students, that is, students are not prepared to debate many of the technical geological points provided as evidence. Also, some of the work sheets provided for the debate include fairly technical geological diagrams, but do not include help with how to interpret them. At the end of the activity, students are given a summary of the actual 1926 symposium on continental drift, with a bulleted list of Wegener’s evidence, including the jigsaw fit of the continents, the matching mountain belts across the Atlantic Ocean, the Mesosaurus fossils found in America and Africa, the evidence of coal found in Antarctica, and ice at the equator. However, this evidence is not further discussed or related to Wegener’s conclusion.


Although most of the ideas are presented, they are usually presented as either a general statement with no supporting examples, or as a few instances with no general explanation. For example, for the idea that the surface of the Earth is continually changing (Idea a), the text provides a statement (level 1, p. 110s) but offers no supporting explanation or examples of continual change. For other ideas, such as that there are several processes that contribute to the changing surface of the Earth (Idea b), the text provides specific examples of the idea, but the idea itself is not stated in general or as a summary for the examples provided. In level B, for instance, Chapter 5: On the Rocks discusses some of the processes that change the surface of the Earth (for example, weathering and erosion [pp. 90–93s]). Later in level 1, the text presents more processes (for example, earthquakes, volcanoes, and other features created by colliding plates [pp. 110–111s, 114–119s]), but there is no mention that any of these processes change the surface of the Earth. These examples are isolated from one another rather than presented as multiple instances of Earth-changing processes. Also, important connections between these key ideas are not made. For example, the idea that the Earth’s surface is continually changing is not related to the idea that several processes contribute to the ever-changing surface of the Earth, and ideas about plate tectonics (Ideas f–h) are not discussed as ways in which the surface of the Earth can change (Idea b).

Occasionally, unrelated or only loosely related ideas interrupt the flow or sequence of the key Earth science ideas. For instance, in level B, as students are to learn about weathering, they also learn about acid rain in general, burning fossils fuels, tests of carbon dioxide and (optionally) measuring reaction rates. At times, the key Earth science ideas seem to be incidental to some of the activities and lessons, rather than the focus.

Beyond Literacy

PRIME Science does a nice job of restricting its treatment of this topic to key ideas and terms that are part of science literacy. However, for the student role-playing activity, some of the work sheets provided for the debate include fairly technical geologic diagrams but do not include help with how to interpret them (level 1, pp. 360–361t). Furthermore, another activity focuses on categorizing types of rocks and uses technical terms such as “quartzite,” “siltstone,” “silica,” “schist,” “mica,” “obsidian,” “breccia,” “slate,” and “hornfels” (level 1, pp. 112–113s, 128–129s, 338–341t, 344–347t). These terms are presented in a lesson that includes a key Earth science idea (Idea c), and hence, could distract students and teachers from focusing on the main idea.


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.