| 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 for 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. |
Food is presented as an energy source only, not as a source of building material. In grade six, at the beginning of Unit 6: Energy and You, students are asked to think about the scientific meaning of energy. A line of questioning is provided in the Annotated Teacher's Edition:
Where does your energy come from? (From the food you eat) Where does the energy in food come from? (The sun) What happens to the energy in food after your body burns it? (It is changed into the energy of motion and body heat, and it is used to build and repair body cells.) [Level Green, p. 314t]
This question-and-answer sequence conveys the idea that food serves as fuel; however, the quality of students' answers is not guaranteed. Next, students are asked to construct a concept map that includes such words as "food," "energy," and "you" (p. 318s). To illustrate energy transformations, the text states that the chemical energy in food enables humans to run or walk (p. 324s).
The idea that organisms get their energy from burning food is stated in grade seven, before the different roles of organisms in the food web are discussed. Plants are classified as producers because "they make food energy"; other organisms are consumers because "they obtain energy by consuming food they did not produce" (Level Red, pp. 28-29s).
In grade eight, before introducing the process of respiration, the text asserts that peanuts (and other foods) contain energy (Level Blue, p. 57s). A series of photographs show grapes, a plate of food, and a running girl, connected by arrows. The caption for the plate of food reads "Energy stored as food" and the one for the running girl reads, "Energy released and used to activate muscles." Students are to write a few sentences about the series of photographs. The sample answer in the Annotated Teacher's Edition states: "Plants use and store the sun's energy as they make food. When people eat this food, directly or in the form of meat, the energy is released and used by the body" (p. 57t).
Idea
b: Plants make their own food, whereas animals obtain food
by eating other organisms.
Idea c: Matter is transformed in living systems.
Idea
c1: Plants make sugars
from carbon dioxide (in the air) and water. In grade seven, Unit 8:
Growing Plants explains that plant cells carry out respiration and that carbon
dioxide is released during the process: In grade eight, after students conduct a few experiments
that involve testing leaves for starch, they are told that food is made in
leaves in the form of simple sugars that join in a specific way later to form
the more complex starch particle (Level Blue, p. 16s). At the end of Unit
1: Life Processes, after a section that deals with respiration in humans (pp.
58-63s), the text states that plants also respire, and students observe respiration
in germinating seeds (pp. 62-63s). However, this activity focuses on gas exchange,
not on the breakdown of sugars or the transformation of matter.
Idea c2: Plants break down the sugars they
have synthesized back into simpler substances—carbon dioxide and water—and
assemble sugars into the plants' body structures, including some energy stores. Many people are surprised
when they learn that plants carry out respiration. The process
of respiration that occurs in plant cells is similar to
respiration that occurs in our own cells; it involves taking
in oxygen that is then used to release energy from stored
food. Carbon dioxide is released during respiration. [Level
Red, p. 522s]
Idea
c3: Other organisms break
down the stored sugars or the body structures of the plants
they eat (or in the animals they eat) into simpler substances
and reassemble them into their own body structures, including
some energy stores. SciencePlus ignores the incorporation of food materials into
organisms' body structures. However, it does provide content
(in grade eight) that matches the idea that foods are broken
down into simpler substances. First, students are told that,
to be used by human bodies, food must be broken down. The text states
that, "It's not just a matter of breaking down the food
into tiny pieces.. It must also be broken down chemically
into simpler water-soluble compounds" (Level Blue, p. 55s).
Then, students are to chew a cracker and taste that it becomes
sweeter as the starch is broken down into sugar (p. 55s).
Next, as an introduction to a lesson on respiration, students
exhale on the palms of their hands and feel the moisture.
They are told that in the lesson, they will learn where
the water vapor comes from (p. 57s). Later in this lesson,
they are told that the process of respiration "produces
wastes" and they conduct experiments that identify the products
of respiration in their breath (p. 61s). Only at the end
of the lesson, when they define respiration and complete
its word equation (p. 62s), is their attention drawn to
the idea that carbon dioxide and water are not "produced
during respiration" but result from the breakdown of digested
foods.
Idea
c4: Decomposers transform
dead organisms into simpler substances, which other organisms
can reuse. SciencePlus
presents the idea that light energy is necessary
for the process of photosynthesis to occur, but not the idea that some of
the light energy is stored in the sugars. In grade six, following an explanation
of the concept of energy transformation in Unit 6: Energy and You students
have to answer some "Problems to Ponder" (Level Green, p. 325s). One problem
asks them to consider a tree as an energy converter and to list its energy
inputs and outputs. However, since the information has not been presented,
students' responses may not include this key idea. In grade seven, Unit 1:
Interactions students are asked to think about how energy moves through a
community of living things and how plants get their energy. The text mentions
that "the process of photosynthesis also requires energy" and that "[g]reen
plants use energy from sunlight to manufacture their food" (Level Red, p.
28s). In grade eight, students get to test for starch leaves grown in the
dark and in the light and are led to conclude that light is necessary for
starch to be produced (Level Blue, p. 14s). In summarizing photosynthesis,
the text states that "[p]lants actually make their own food in their leaves.
To do this, they need energy from the sun plus two raw materials: water and
carbon dioxide" (p. 14s). Then students are asked to identify the source of
energy for photosynthesis and are given the word equation is given (p. 16s).
Later in the chapter, students are told that chlorophyll absorbs sunlight
energy and puts this energy to work, "chemically combining carbon dioxide
and water to form sugars" (p. 24s). None of these statements mention that
some of the light energy is transformed and stored in the sugars, and
students might infer that light energy is required to carry out the photosynthesis
reaction only.
Idea
d: Energy is transformed in living systems.
Idea d1: Plants use the energy from light
to make "energy-rich" sugars.
Idea
d2: Plants get energy
by breaking down the sugars, releasing some of the energy
as heat.
Idea
d3: Other organisms get
energy to grow and function by breaking down the consumed
body structures to sugars and then breaking down the sugars,
releasing some of the energy into the environment as heat. The text also deals with heat production in compost
piles. In grade six, in Unit 3: It's a Small World (Level
Green, pp. 128-197), the text describes compost piles and
states that "[h]eat is produced as the material decays"
(p. 153s). Students are then to make compost piles, observe
the changes over several weeks, and explain the increases
in temperature. This idea is treated again, but more substantially,
in grade eight, in the context of digestion and cellular respiration. The
text states that for the energy in food to be used by human bodies, the food
must be broken down into simpler substances (Level Blue, p. 55s). Students
then are asked to examine photographs of grapes, a plate of food, and a running
girl, connected by arrows (p. 57s). The caption for the plate of food says,
"Energy stored as food," and the one for the running girl says, "Energy released
and used to activate muscles." Students are to write a few sentences about
the photographs. The sample answer given in the Annotated Teacher's Edition states: "Plants use and
store the sun's energy as they make food. When people eat this food, directly
or in the form of meat, the energy is released and used by the body." Students
are asked to compare the release of energy from food to the release of energy
in gasoline or candle wax; they are expected to respond that all cases involve
"burning" and require oxygen and that the burning that occurs in cells is
the slowest (p. 57t). Later, students are asked what the fact that they get
hot when they exercise suggests about the relationship between respiration
and burning (both give off heat) (p. 60s), and the text presents the word
equation for respiration (p. 62s).
Energy makes things happen
only when it is converted from one form to another. For
example, chemical energy in the food you eat enables you
to run or walk. You are an energy converter. As you
move, the chemical energy in the food is changed into the
energy of motion. Are there any other types of energy produced?
(Other types of energy produced when you move are heat and
sound energy.) [p. 324st]
Idea
e: Matter and energy are transferred from one organism
to another repeatedly and between organisms and their
physical environment.
In grade seven, in the context of food chains and webs, the text
describes how energy moves through a community and asks
students to make an energy diagram that contains the items
identified as "producer," "sunlight," "carnivore," and "herbivore"
(Level Red, p. 30s). Teachers are told to ask students to
identify where they get their energy, the organisms that
it comes from, where various organisms get their energy
(from the food they eat), and also to "[h]elp students recognize
that the energy they receive from food has already passed
through several other organisms before it reaches them"
(p. 32t). No attention is given to the cycling of matter
between organisms and their physical environment.
However, in several instances, students are expected to reach conclusions that are not justified by their observations. For example, in Exploration 1: The Search for Starch (Level Blue, pp. 7-9st), eighth-grade students get to observe that iodine turns blue-black in the presence of cornstarch and are expected to conclude, therefore, that plants have made starch when they observe the blue-black color change in leaves grown in the light versus leaves grown in the dark. Strictly speaking, however, this conclusion is not valid because students are not told that iodine turns blue-black in the presence of starch only and not in the presence of any other substance. (As far as students know, iodine might turn blue-black in the presence of other substances too, so that it could not be concluded definitely from the presence of a blue-black color that starch is present, rather than something else.) The text also describes van Helmont's experiment and his mistaken conclusion: "Therefore almost seventy-four kilograms of wood, bark, and roots arose out of water only" (p. 11s). While students are led to decide that van Helmont "made a major mistake when he concluded that water alone was completely responsible for the increase in mass in plants" (p. 12s), in fact, all he could conclude reasonably was that soil does not account for the increase in mass, not what does account for it.
The set of key life science ideas that serves as the basis for this analysis tells a story of matter and energy transfer and transformation that spans several levels of biological organization-ecosystems, organisms, cells, and possibly molecules. Links between life science and physical science are particularly important; one such link is that which links the transformation of matter and energy in physical systems (where it may be easier to keep track of the inputs and outputs of matter and energy).
SciencePlus is an integrated program in that it distributes Earth, life, and physical sciences over the three grades (rather than including the content of a single discipline in a particular grade). Each unit focuses on one discipline but includes content from other science disciplines that "supports the major content focus of each unit and helps achieve integration" (p. T20). What are the implications of this organization for coherence in the presentation of Ideas a-e? While SciencePlus treats all of the key life sciences ideas, in most cases, it focuses on the flow of energy, rather than on matter cycling between organisms. For example, food is discussed as an energy source only, and the incorporation of building materials from food into organisms' body structures is ignored. Emphasizing energy over matter may make sense in elementary school, where the ideas to be learned are cast in terms of "needs of organisms" (e.g., see Benchmarks for Science Literacy [American Association for the Advancement of Science, 1993], benchmarks 5EK-2#1 and 5E3-5#2). However, in the middle grades, where the ideas emphasize transfer and transformation, energy is much more abstract. It may be difficult to convey energy transfer and transformation without prior attention to matter transfer and transformation.
Four units in SciencePlus treat different aspects of the key ideas, and the program could benefit from cross-referring students (or teachers) to previous relevant experiences. Several opportunities for making meaningful links are missed, as discussed below:
Although Earth, life, and physical science units are distributed throughout the three SciencePlus textbooks, no attempt is made to alert teachers or to remind students about relevant experiences from other disciplines when they might be helpful to understanding the key life science ideas. In grade six, for example, students are to investigate burning and corrosion while learning about chemical changes and mass conservation (Level Green, pp. 296-300s). But when studying cell respiration in grade eight, neither students nor teachers are reminded about these experiences. Rather, the text merely mentions that burning and cell respiration give off the same waste products (Level Blue, p. 62s). Similarly, even though students have had experiences with energy transformation in physical systems (Level Green, pp. 319-322s) and a comparison is made of the energy inputs and outputs when wood is burned in a stove versus when food is converted to kinetic energy in a lion (p. 324s), no connection is made later in the eighth-grade unit on photosynthesis and respiration (which also involve energy transformations).
The 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 life science examples of the kinds of misleading illustrative materials of most concern to the evaluation teams:
The use of imprecise or inaccurate language is problematic in text and teacher materials, not solely in illustrations. In life science, one significant problem is that imprecise language in explanations of energy transformations can reinforce students' common misconception that matter and energy can be interconverted in everyday chemical reactions. For example, presenting the overall equation for cellular respiration in which energy appears as a product without indicating where the energy was at the start can lead students to conclude that matter is converted to energy. Similarly, presenting the overall equation for photosynthesis in which energy appears only as a reactant can lead them to conclude that energy has been converted into matter.
