| 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. |
There is not a content match. Although the student text discusses Earth-changing processes, the emphasis is on recurring processes rather than on a continually changing surface of the Earth:
[T]he processes that formed the earth are still taking place today. Volcanoes are still erupting, and they have erupted many times before. They are an example of molten rock breaking through the surface. This molten rock has cooled and has formed the hard surface of the earth. This process is still going on. [p. 180s]
The introduction to Unit 2: Explanation for the Patterns of Change on Earth and Beyond briefly mentions that patterns in the layers of the Earth explain how the Earth has changed over time (p. 137s), but the unit's chapters provide no evidence of a changing Earth's surface. Overall, the explanations, diagrams, and questions provided do not focus on how these processes continually change the surface of the Earth (e.g., pp. 187-191, 214-218s). More importantly, no part of the student text or Teacher's Edition provides a contrast to the commonly held student idea that the surface of the Earth is static and unchanging.
The Teacher's Edition shows the changes in the locations of the continents over time (pp. 220-221t) but does not explain that the surface of the Earth is continually changed by the motion of continents. In another instance, it mentions that earthquakes have occurred throughout human history (157a-157ct), but does not mention how earthquakes have changed the Earth's surface.
Idea
b: Several processes contribute to changing the
Earth’s surface. Although the student text presents a few
geological events (e.g., faults [p. 215s] and volcanoes [pp. 216-217s]), it
does not focus on the changes made to the surface of the Earth.
There is a content match. The text describes processes of mountain
formation, including folding and faulting (pp. 214-215s), and a question asks,
"[H]ow does the landscape change after a severe earthquake?" (p. 213s). Unfortunately, other Earth-shaping
processes such as weathering, erosion, and deposition, are not mentioned.
The Teacher's Edition provides information
about how volcanoes can lead to mountain formation-information that is to
be presented in a class discussion or assigned as an additional reading:
Mauna
Loa is the world's largest volcano and the largest single
mountain in terms of volume. It rises nearly 4200 meters above
sea level and fully 9000 meters above the seafloor. It is
approximately 100 kilometers in diameter, with a circumference
approaching 320 kilometers. All this immense bulk has been
built up by intermittent lava flows over many thousands of
years. [p. 157ct]
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 idea is stated once in the Teacher's
Edition (p. 163t) and once in the student text (p. 180s). In the student
play, the character James Hutton says, "[T]he processes that formed the earth
are still taking place today" and gives the example of volcanoes (p. 180s).
But this idea is not further developed, nor is it linked to other geological
events. Furthermore, the play also contains several antiquated ideas about
the causes of earthquakes and volcanoes (e.g., pp. 164s, 167-168s, 169s),
but does not help the students distinguish which ideas are scientifically
sound and which are not. Students might not be able to discern that Hutton's
idea is still accepted today while Strabo's idea (that wind pushes ash and
rocks into the air as volcanoes erupt) is not.
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. The Teacher's Edition also provides information about abrupt
and slow processes that could be used in class discussions or as supplemental
readings. The chapter 9 Background Information feature explains that earthquakes
occur without warning, that the building of a volcano in Mexico occurred over
months, and that the islands of Hawaii have been built over many thousands
of years (pp. 157a-157ct).
There is a content match. The introduction to Chapter 9: Volcanoes,
Earthquakes, and Explanations asks students to think about the fact that earthquakes
and volcanoes can be sudden events (p. 157s). Although the student text mentions
briefly that some processes can be sudden, these two sudden events are not
contrasted with slower or more subtle geological events. Later, students read
that North and South America are moving away from Africa at a very slow rate,
(p. 198s), and diagrams of the Earth show the past locations of continents
(pp. 220-221s). However, none of these sightings mentions how the rate of
the event is related to the change on the surface of the Earth.
Idea
e: Slow but continuous processes can, over very
long times, cause significant changes on the
Earth’s surface. (Unfortunately the preceding passage is marred
by obvious arithmetic errors.) Later, the student text shows the positions
of continents at various points on a geologic timeline
(pp. 220-221s). However, the accompanying text does not explain how the slow
change over long times can cause a significant change to the surface of the
Earth. This idea is not mentioned in any other context, such as the
wearing down of mountains or building up of sediment.
There is a content match. The Teacher's Edition suggests that teachers present
and illustrate this key idea when introducing an activity on moving continents:
Introduce
Part A of the investigation as follows. Point out that the
procedure tells them that North America and South America
are moving away from Africa and Europe at a rate of about
2.5 centimeters per year. Point out this distance on a metric
ruler. Help them grasp the implications of this. It might
not seem like much in the short term-this is about half as
fast as a fingernail grows. In the last 10 years these continents
have moved apart by 25 centimeters. Although this is not very
far, it translates into large distances over long periods
of time; 250 centimeters (8 feet) in 100 years, 24 meters
(80 feet) in 1,000 years, about 1 kilometer (0.6 miles) in
10,000 years, 10 kilometers (6.2 miles) in 1 million years,
and about 2,000 kilometers (3226 miles-more than a third of
the distance across the United States) in 200 million years,
if we assume a constant rate of movement. [p. 198t]
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. Diagrams of Pangaea and the fossil evidence (that similar fossils
found on now far spread continents) are included in Blackline Masters (Teacher's
Resources Book, Assessment Tools, BLM 10.3, BLM 10.4).
There is a content match. The student text presents the idea in the
context of describing Wegener's theory of continental drift:
Wegener
thought that because the shapes of continents fit together
like a puzzle, it was likely that the continents had been
together at one time and later moved to their present location..
[G]eologists found fossils in Africa and Australia that were
similar to fossils in South America and Antarctica.... This
evidence suggested that the continents had been together but
then moved apart. [pp. 199-200s]
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 described in both the Teacher's
Edition (pp. 195-196t) and the student text. Students
read that "continents sit on top of plates that make up the
entire surface of the Earth. It is these plates that move..
[A]s the plates rub against each other, they cause earthquakes.
Volcanoes occur where plates move apart or where one plate
pushes and melts beneath another plate" (pp. 201-202s). A
map in the student text shows the Earth's major plates and
how they are interacting (that is, pushing together, pulling
apart, or moving side by side) (p. 202s).
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.
The student text explains and illustrates how volcanoes, earthquakes, ridges
and trenches are related to plate boundaries (pp. 201-211s). Furthermore,
the Teacher's Edition encourages teachers to introduce the reading
by having students "compare the diagram of plate boundaries in their book
(Figure 10.2) with the locations of earthquakes and volcanoes shown in Chapter
9" (p. 200t).
Patterns of Change attempts to build a case for the theory
of plate tectonics by presenting the evidence and conclusions as they were
arrived at historically. However, the attempt to develop the theory by unfolding
the evidence may be quite difficult for sixth-grade students to comprehend.
Hence students may be left with little understanding of both the key Earth
science ideas and ideas about how science works. Chapter 9 presents evidence for the theory of plate tectonics. Students
examine maps of the ocean floor, the locations of volcanoes, the locations
of earthquakes, and the ages of rocks (pp. 186-189s). Accompanying questions
encourage students to find patterns in these data, but they are not helped
to link the data to the theory of underlying moving plates at this time. In
chapter 10, students observe that existing continents can be fitted together
like pieces of a puzzle (pp. 197-199s), and they read about Wegener's newsprint
analogy and additional evidence from fossils and the locations of earthquakes
and volcanoes that led scientists to conclude that continents have moved (pp.
199-201s). Although the text presents some of the evidence-such as the existence
of similar fossils on widely separated coasts-it 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. And when the text finally presents the theory of plate tectonics,
it only briefly relates it to the evidence: Students are expected to relate the evidence to the theory in responding
to Stop and Think questions: 2.
How does the theory of plate tectonics explain earthquakes? [Answer:
Earthquakes are the result of two plates rubbing against each other or the
result of one plate moving beneath the other.] 3.
According to the theory of plate tectonics, why are the youngest
rocks in the Atlantic Ocean in the middle of the ocean? [Answer: In the middle
of the Atlantic Ocean, two plates are pulling apart from each other. Where
these plates pull apart, new lava rises up and cools. This lava is younger
than the rock to either side. [Questions 1-3: pp. 202s,
200-201t] 4.
How does the theory of plate tectonics explain why the continents
are moving? [Answer: The theory of plate tectonics explains that the continents
are moving because they are part of moving plates that cover the earth's surface.] 5.
How does plate tectonic movement explain the formation of volcanoes?
[Answer: Plate tectonic movement explains the formation of volcanoes in at
least two ways: b.
Where plates spread apart, lava rises up and volcanoes form (such
as on the ocean floor).] 6.
Use the theory of plate tectonics to explain the correlations you
saw between the locations of volcanoes and earthquakes. [Answer: The correlation
between volcanoes and earthquakes is that often they both occur in the same
locations. Typically both occur along plate boundaries. For example, both
earthquakes and volcanoes occur at trenches at ridges. Volcanoes are less
common along transform faults.] [Questions 4-6: pp. 204s,
201t] However, since some of the required answers are not provided in the
reading, it is not clear how students will come up with these answers or make
the connection between the evidence and the explanation. Occasionally, the text misrepresents the nature of science. For example,
the text states that "to test his theory of continental drift,
Wegener used a very simple analogy. He pointed out that if
a sheet of newspaper is torn in half leaving jagged edges,
we should be able to fit it back together based on its shape
as if it were a puzzle" (p. 199s). This may leave the impression
that developing an analogy is an adequate way to test a theory.
Also, some of the conclusions drawn from the evidence do not
seem logical. For instance, the text explains that "scientists
found tropical plant fossils on ice-covered Antarctica. This
evidence indicated to some geologists that at one time the
continents were much closer together and more similar" (p.
201s). However, the logical conclusion from the evidence provided
is that either the climate of Antarctica has changed dramatically
or the location of Antarctica has changed dramatically.Geologists
concluded that the surface of the earth is moving, but it
is not just the continents that are moving. Geologists continued
to explain that the continents sit on top of plates that make
up the entire surface of the earth. It is these plates that
move (see Figure 10.2). We call this explanation the theory
of plate tectonics. According to this explanation, as the
plates rub against each other, they cause earthquakes. Volcanoes
occur where the plates move apart or where one plate pushes
and melts beneath another plate. This also explains why the
rocks are youngest in the middle of the Atlantic Ocean. Along
the Mid-Atlantic Ridge, two plates are pulling apart and new
lava is rising up between them. As this lava cools, it forms
the youngest rocks. [pp. 201-202s]
1.
List some of the patterns that scientists noticed but did not know
how to explain. [Answer: Geologists noticed patterns in the shapes of continents
and the locations of fossils, volcanoes, and earthquakes.]
a.
Where one plate sinks beneath another, the sinking plate melts, magma
rises, and eventually escapes through the top of the upper
plate. Volcanoes form where the molten rock escapes.
Patterns of Change
presents
most of the key Earth science ideas. However, one of the most
important ideas-the idea that the surface of the Earth is
continually changing (Idea a)-is not addressed. In many ways,
this key idea is a precursor to the other ideas that explain
how the surface of the Earth changes. These other ideas
(Ideas b-h) may be less credible for students if they do not
understand that the Earth continually changes. For the idea that several processes contribute
to the changing surface of the Earth (Idea b), very few Earth-changing processes
are discussed. Although the emphasis of chapter 10 is on the more abstract
process of plate tectonics, directly observable processes such as weathering,
erosion, and deposition are not mentioned. For the other ideas, many of the experiences
are not tied together. For example, the text gives examples of both abrupt
(volcanic eruptions and landslides) and very slow processes (movement of tectonic
plates), but presents them about 40 pages apart and never discusses or compares
the range of rates of Earth-changing processes. The material makes a serious effort to relate key Earth science ideas
to their historical development and to
the nature of science. Ideas about the nature of science are introduced earlier
in unit 2-in Chapter 8: Scientific Explanations Begin with a Question. They
are then developed in the next two chapters in the context of presenting
the key Earth science ideas. However, the primary learning goals seem to be
those related to the nature of science. Key Earth science ideas seem to be
used to develop nature of science ideas, as explained in the Teacher's
Edition: Ancient and disregarded ideas about earthquakes
and volcanoes are presented alongside current scientific ideas. Unfortunately,
students are not given much help in distinguishing between the ideas presented
until much later. Hence, the structure and sequence of lessons in this unit
may work against student understanding of these key Earth science ideas.In this unit, the students study the nature of science
by exploring the theory of plate tectonics and its relationship
with associated patterns on earth. The theory of plate tectonics
is an excellent vehicle for learning about the nature of science
because it exemplifies key features of the scientific enterprise.
[p. 141at]
While the text does a nice job of restricting its treatment of this
topic to key ideas and terms that are part of science literacy,
its presentation of the key Earth science ideas near the beginning
of grade six (level A, unit 2) seems too early for most students
to follow. While National Science Education Standards
(National
Research Council, 1996) includes these key ideas in content
standards for grades 5-8 (pp. 159-160), Benchmarks for
Science Literacy (American
Association for the Advancement of Science, 1993) postpones
the theory of plate tectonics and its explanation in terms
of heat convection, gravity, and density until grades 9-12
(p. 74). Without an understanding of how moving plates can
be explained by underlying physics principles, the theory
may seem to have been pulled out of thin air. In addition,
the historical presentation of the key ideas adds further
sophistication because students are expected to follow the
logic as the story unfolds (even though few scientists did
so at the time). The Teacher's Edition provides no
rationale for treating this topic so early.
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:
- 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.
