|Earth Science||Life Science||Physical Science|
1. About this Evaluation Report 2. Content Analysis 3. 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.|
There is a content match. Several statements in the student
text explain that the Earth or surface of the Earth is changing
continually. For example, one unit opener explains that
the forces that sculpt, or change, Earth’s rocky
surface never complete their work. Around the clock, rivers
pick up rocks, carry then along, change them, and put
them down somewhere else. Day and night, wind blows against
rock, grinds them down and carries them off. Inside Earth,
processes work unceasingly to create rocks or change them.
[Earth’s Solid Crust, p. 6s]
the forces that sculpt, or change, Earth’s rocky surface never complete their work. Around the clock, rivers pick up rocks, carry then along, change them, and put them down somewhere else. Day and night, wind blows against rock, grinds them down and carries them off. Inside Earth, processes work unceasingly to create rocks or change them. [Earth’s Solid Crust, p. 6s]
This idea is discussed in other contexts, such as mapmaking and land features in national parks (Unit 35: Earth’s Solid Crust, pp. 58–59s, 71s, 80s, 91s; Unit 40: Earth Changes Through Time, p. 108s).
b: Several processes contribute to changing the
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. The student text explains that scientists assume that the Earth-changing processes seen today are the same processes that have operated in the past. The text provides a simple example: “If gravity causes a rock to fall from your hand to the ground today, you can assume that if you had been around 20 million years ago, gravity would have caused a rock to fall to the ground then” (Earth's Changes Through Time, p. 17s). Then, an example of an Earth-shaping process is given. The text explains that, “If water flows downhill today, it is safe to assume that it has flowed downhill ever since water started flowing” and that, “If you found an ancient river, you could assume that its banks eroded in some places and sand was deposited in other places, too” (Earth's Changes Through Time, p. 17s).
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.
e: Slow but continuous processes can, over very
long times, cause significant changes on the
Earth’s surface. The landscape at Arches National Park is described as being
created over a long time period as well, but the slow process
of change is not explained explicitly: “Windblown
material, precipitation, and runoff subjected the sandstone
to weathering and erosion for millions of years. Gradually,
these agents of change carved holes in the sandstone”
(Earth's Solid Crust, p. 69s). Lastly, although
the slow rate of motion of the tectonic plates is not mentioned
in the text, a side feature called Math Link asks students
to calculate how long it will take Los Angeles to move to
San Francisco (Earth Changes Through Time, p. 96s).
Flash flooding, combined with the
effects of wind and other agents of erosion, cause the rim
of the canyon [Bryce Canyon] to erode at the rate of 30
centimeters (1 foot) every 50 years. Over millions of years,
water has eroded the limestone, sandstones and shales in
Bryce Canyon to form a fantastic collection of spires and
craggy columns. [Earth's Solid Crust, p. 59s]
The landscape at Arches National Park is described as being created over a long time period as well, but the slow process of change is not explained explicitly: “Windblown material, precipitation, and runoff subjected the sandstone to weathering and erosion for millions of years. Gradually, these agents of change carved holes in the sandstone” (Earth's Solid Crust, p. 69s). Lastly, although the slow rate of motion of the tectonic plates is not mentioned in the text, a side feature called Math Link asks students to calculate how long it will take Los Angeles to move to San Francisco (Earth Changes Through Time, p. 96s).
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.
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.
h: Landforms and major geologic events, such as
earthquakes, volcanic eruptions, and mountain
building, result from these plate motions.
Fossils provided further evidence. They showed that, long ago, the same plants and animals existed on different continents at the same time. This is quite unusual because, as you know, specific plants and animals are limited by their habitats and their environments. Finding the same animal or plant in both Africa and South America would imply that they had, at one time, closely similar environments. [Earth Changes Through Time, p. 48s]
Furthermore, the text explains that the seeds for the Glossopteris plant (fossils of which have been found in India and Australia) were too big for the wind to blow them across an ocean and that it is unlikely that the same plant would develop in exactly the same way on isolated, separate continents. Similarly, the evidence for matching rock layers is presented and explained:
First, the rock record on the boundaries of different continents was observed, analyzed, and interpreted. The beds of rock, you recall, allow us to interpret the history of Earth at that place. Dating of rocks can tell us about when they formed…. In many places, older rock layers along continental boundaries matched well. Recently formed layers showed differences. (In terms of Earth’s history, a 100-million year old rock is recent.) The differences could represent what happened after the continents split apart. [Earth Changes Through Time, p. 48s]
Lastly, the fossils of tropical organisms found in Antarctica, which now has a cold climate, are explained: “What did this evidence mean? At one time, this region must have been much warmer. At that time it was located near the equator, where such plants and animals live” (Earth Changes Through Time, p. 49s). Then, these lines of evidence are related to the conclusion: “The fit of the continents, the similarities of the rock record, fossils of similar plants and animals, and evidence of similar climates were the clues scientists had” (Earth Changes Through Time, p. 49s).
Furthermore, students are given a chance to think about some of the evidence. At the end of the continent-matching activity, students are asked several questions such as, “What does the evidence of fit for shapes and features tell you about the continents and their relative positions?” and, “If you lived 10 or 20 million years from now, how would you be able to figure out the relative positions of the continents of the 20th century?” (Earth Changes Through Time, p. 47s).
However, although many experiences and examples for each idea are provided and some links are made between ideas, there is almost no attempt to tie together all the individual experiences provided for the key ideas. For example, information about the many processes (streams, glaciers, wind, volcanoes, and earthquakes) that shape the Earth is presented, but there are no statements, questions, or activities that focus students on the fact that several of these processes often act at the same time on the same land feature—as, for example, when mountains are built up at the same time that erosional forces are at work tearing them down.
Other coherence problems stem from occasional inappropriate topic sequencing and unrelated topics added. For instance, the text presents how water, wind, ice, and gravity all change landforms on the surface of the Earth (Earth’s Solid Crust, pp. 50–71s) even though the more general topic of “What are Landforms?” is not introduced until the next chapter (Earth’s Solid Crust, p. 76s). In another instance, a feature called Science, Technology and Society focuses on shoreline erosion (Earth’s Solid Crust, p. 48s), even though the process of erosion is presented in the following chapter. Interesting sidebar notes and activities are usually separated from the text by a box. However, sometimes the text is interrupted with interesting and unrelated facts, such as careers or myths and legends, making it more difficult to focus on the important Earth science ideas (e.g., Earth’s Solid Crust, pp. 37s, 39s, and Earth Changes Through Time, p. 82s).
Other connections to relevant ideas in science are made. For example, some of the key Earth science ideas are well connected to the role of models in science. The theme of models is used throughout the Earth Changes Through Time unit as the theory of plate tectonics is presented. In the unit introduction, the teacher is alerted to the Theme Connection of models (p. 6t) and students read that, “In order to understand Earth’s processes, you can create a model by making observations of changes and patterns on Earth” (p. 7s). Throughout the unit, the text describes how scientists have changed their model of Earth processes as new evidence is discovered. For instance, lesson 5 begins by explaining that, “In this lesson you will find out how the pattern of earthquake and volcano distribution helped geologists modify their model of Earth processes” (p. 70s). Similarly, lesson 6 begins with, “In this lesson you will see how all of the bits and pieces of evidence you’ve seen so far and some new pieces add up to give us our current models of Earth processes” (p. 84s). Although models are a unifying theme for the unit, there is little attention given to the models that students make in the activities throughout the unit. Many activities have students make models of Earth processes (e.g., Earth Changes Through Time, pp. 18s. 19s, 20s), yet students are not asked about the usefulness or limitations of their models or how different models can be used to represent the same thing.
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.