Introduction

Much of science teaching is guided by and based upon the contents of science textbooks. Gatherings of science educators frequently condemn this practice, as they recommend more and better hands-on science activities in the K-12 curriculum. If we look carefully at classroom practice and textbooks however, we might ask, "Is it the books themselves that are the problem or is it the manner in which students and teachers use them?" This article presents a rationale and strategies for teachers to facilitate meaningful learning from science textbooks.

Constructing Meaning

Over the past 20 to 30 years, views of how learners acquire knowledge has shifted from behaviorist theories of the 1950s and 60s to a "constructivist" view (e.g., von Glaserfeld, 1981). The constructivist view of knowledge acquisition holds that learning is a process of connecting new knowledge to existing knowledge, involving active engagement of the learner's mind. What we learn from any experience, including the experience of reading, depends upon what we already know and how we choose to "connect" our knowledge with the sensory input we perceive. Said differently, we use what we already know to make sense of what we don't.

Reading researchers have acknowledged for some time that reading is a process of active construction of meaning; and, the ideas supporting constructivism are well-documented by research on comprehension of written text (Bransford, 1979; Spiro, 1980). A number of studies have shown how a reader's knowledge interacts with text to influence comprehension, recall, and usefulness of what is read. For example, in a study described in Bransford (1979), readers were given the passage below to read and comprehend. Read the passage and see if you think it is easy to understand.

The procedure is actually quite simple. First you arrange items into different groups. Of course one pile may be sufficient depending on how much there is to do. If you have to go somewhere else due to lack of facilities that is the next step; otherwise, you are pretty well set. It is important not to overdo things. That is, it is better to do too few things at once then too many. In the short run this may not seem important but complications can easily arise. A mistake can be expensive as well. At first, the whole procedure will seem complicated. Soon, however, it will become just another facet of life. It is difficult to foresee any end to the necessity for this task in the immediate future, but then, one can never tell. After the procedure is completed one arranges the materials into different groups again. Then they can be put into their appropriate places. Eventually they will be used once more and the whole cycle will then have to be repeated. However, that is a part of life (Bransford, 1979; p. 134-135; original study by Bransford & Johnson, 1972).

Most readers find this description of a procedure difficult to understand when read without a title. When the title was provided, readers had no difficulty following the paragraph. The title was "Doing the Laundry!"

Why is this non-technical description of a familiar procedure so difficult to make sense of without its title? Most of us have prior knowledge to understand the paragraph, but are unable to use it without the "cue" or "context" which the title provides. If we are reasonably good readers, we probably tried to make sense of the sequence of sentences as we read along; we might have had one or two tentative hypotheses about the topic of the paragraph as we struggled to construct some coherent meaning for ourselves. If we are less persistent and resourceful readers, we might have given up halfway through the paragraph in frustration, concluding that it simply "made no sense."

Now read the following paragraph from a popular high school biology textbook:

Water enters the mouth, where it passes over the gills on either side of the head. The water is then forced out through separate pairs of gill slits. The gills are respiratory organs of the fish. The shark has large, well-developed eyes on either side of the head above the mouth. Paired nostrils on the ventral side if the head lead to olfactory sacs. These olfactory sacs sense odors in the water. As already mentions, shark skeletons are made up of cartilage rather than bone.

Unless you have recently taught a unit on "Class Chondrichthyes," you might not have recognized this passage as a description of the respiratory system of the shark. Even when presented in the context of the printed textbook page, this passage is difficult to visualize in any concrete manner. Now, imagine you are a science-indifferent or science-phobic tenth grader with poor-to-average reading skills. How will you make sense of this passage? Even if you want to try, will you have the skills to do so? And why should you struggle to understand the passage to begin with?

Difficulties in Learning from Science Textbooks

The effort a reader puts into comprehending or making sense from text depends on several factors. The reader's purpose in reading is foremost among these. We tend to put more effort into figuring out things we really want to know. Our purpose also prescribes the context for the connections we will make between the information we are reading and what we already know. For example, readers who are told to compare and contrast ideas in a passage tend to read more slowly and to recall ideas in a compare/contrast structure. In many science classes, the traditional approach to using a textbook is to have students read a chapter and answer questions typically found at the end of the chapter. The questions tend to be low in cognitive level, inviting a search-and-find learning strategy (Stake & Easly, 1978; Tobin & Gallagher, 1987). Since answering these questions is their only purpose, students tend to engage at a very low cognitive level. Therefore, we should hardly be surprised that many students fail in the difficult task of making meaning from science prose.

The shallow purpose students are given for reading presents the first of several difficulties students have in learning from science textbooks. The low cognitive demands of such assignments discourage students from actively making meaningful connections to their existing knowledge and from actively monitoring their comprehension. When difficult passages are encountered, many students simply skip them, rather than undertake the effort to sort out a meaning for themselves.

Second, most science textbooks (particularly middle and secondary level books) are written in an impersonal, seemingly objective tone, which ignores the readers' needs. The style seldom offers invitations to the reader to access or "check-in-with" his or her prior knowledge about a topic. Textbook authors write as if the reader has as much prior knowledge as they do; and, they assume that readers are familiar with the style and structure of expository writing.

A third problem in learning from science textbooks is that many do a poor job of making connections clear between ideas within the text. One of the unfortunate casualties of applying readability formulas to science writing is that many of the linking connections, such as "because," or "therefore," are removed in the interest of creating shorter sentences. Long, technical words are used only once to keep the word-length count down, when using them repeatedly might allow students to understand the terms through their contexts of usage (Schallert & Tierney, 1982). The abundance of technical words in science textbooks adds to the problem of identifying key ideas and their interconnections.

Lastly, successful comprehension also depends on the relevant prior knowledge a reader has. This includes knowledge about the topic of the text and about the conventions of writing. Good readers appear to utilize their knowledge of text and purpose and to monitor comprehension in an almost automatic fashion; poor readers are unaware or uninformed of the knowledge they need and often are lacking in metacognitive skills as well (Brown, Campione, & Day, 1981).

Alternate Ways to Use and Learn from Science Textbooks

Given the difficulties outlined above, the reactionary stance has been "Don't use textbooks in science." This stance, however, seems to "throw the baby out with the bathwater." If we want our students to be scientifically literate, surely they should be able to learn about science issues through reading critically about them. Also, we should remember that the "standard" list of science process skills is only a partial list of what scientists actually do. Scientists read and learn from their reading. Like scientists, students can obtain useful knowledge from textbooks.

In order to get students to learn from their textbooks in more meaningful ways and to use their textbooks in more resourceful ways, we, as teachers, need to examine our beliefs about the role of the textbook in our teaching. Are we being overly-dependent on the contents of the text in our science teaching? Or, do we see the textbook as only one of many resources we can provide our students? Are we emphasizing learning about the products of science; or, does our teaching emphasize the processes of science and how science knowledge is created? How we view the role of the textbook strongly affects the way our students will perceive the textbook and the nature of science. In using textbooks, we should assist our students to become more active and constructive readers of science prose.

Meaningful purposes for reading. The most powerful strategy we, as teachers, can implement is to provide our students more meaningful purposes for reading; and more meaningful texts to read (Schallert & Roser, in press). If we reflect on the purposes scientists have for reading, we can discover other uses for textbooks to promote meaningful learning. Scientist read to (1) obtain background or explanatory information for a project; (2) obtain data that other scientists have already published and (3) to challenge their own ideas with new viewpoints. In essence, they read because they have questions which can be answered by reading. The questions tend to be purposeful and research or project related.

The key to providing meaningful purposes for reading is to have the students determine their own purpose for reading. Have students generate their own questions to answer using the textbook, or other resources. Meaningful questions can arise when students conduct hands-on experiences prior to reading relevant portions of their textbook. During the hands-on activity, students are told to record all questions that arise. The questions are categorized into those that need more experimentation to answer, and those that could be answered through reading. Students use their books to find answers to their own questions. In this way, the textbook becomes a resource, in the way that you, as a teacher, probably use your own books.

You can probably think of strategies in which one or more textbooks can be used as data resources. A useful practice is to have students use several texts to gather information. In doing so, they learn that authors present information differently; and, even established "facts" will vary from book to book. Learning can occur as students argue about and discuss variances they have found.

There are other opportunities for creating meaningful purposes in reading textbooks. For example, you can help students to identify a conclusion that the textbook author has drawn. Students are then directed to look back in the text and assemble the evidence the author has presented for the conclusion. Students can evaluate the conclusion both in terms of the evidence presented and the outcomes of hands-on performed in class. Similar conclusions in other textbooks can be analyzed for evidence presented there. Here, students have an analytical purpose in reading. The strategies given here can also be used in reading scientific articles. By using a number of text resources in your class, you demonstrate to students that science information does not "live" in one textbook, but can be gained from many different books and viewpoints.

Understanding science prose. Strategies to assist readers to understand expository prose involve identifying key topics or ideas and the relationships among them. Traditional outlining of a chapter generally fails to identify the nature of the relationships among ideas. Graphic strategies, such as networking, relational mapping, schematizing (Holley & Dansereau, 1984; Mayer, 1987) and concept mapping (Novak & Gowin, 1984), assist the reader to show in a "web" or interconnected visual form how key ideas are related to one another. These techniques are easy to learn with practice, and assist students in recognizing the connections among ideas in texts.

Students' personal "maps" of ideas can be related to text readings. Prior to reading, students can map their understanding of how concepts (preferably those they come up with) are related to a particular topic. As they read, they can add to their map or revise it, in light of the information presented. Or they can make a map of the reading and compare it to their own.

Strategies for metacognition.  Metacognition refers to how we know or think about our thinking or comprehension processes. Good readers tend to know when they are having difficulty comprehending a text and they automatically put in extra time and effort to "untangle" the difficult prose. Readers who do not automatically monitor their comprehension can practice strategies to do so. Any process that involves checking one's understanding is a metacognitive strategy.

The graphic learning strategies described above are metacognitive strategies because they encourage students to assess their understanding. As students work to identify key ideas and relationships they are engaged in thinking about what they are reading. Another strategy is to read and summarize, paragraph by paragraph or section by section. Have pairs of students read together and discuss each section they read. The students would need to agree on their understanding of the section. Their consensus can be written out, to create a summary of the reading. Students in pairs can also write questions for each other about particular sections taking turns asking and answering the questions.

Still another metacognitive strategy is to give students a "checklist for comprehension" to accompany their reading assignments. The checklist might be as simple as a 5-point "comprehension" rating scale, which is checked for each paragraph read. Paragraphs which are rated low in comprehensibility by an individual student can be involved in further class discussion or in individual assistance.

All of these suggested strategies are intended to assist students to pay attention to their comprehension. Learning to monitor breakdowns in comprehension is a necessary step toward the goal of learning more effectively from a textbook (Brown, Campione, & Day, 1981).

Summary and Conclusions

Textbooks have a role to play in science learning, although that role is vastly different from the traditional role. This point is critical. The traditional student-reads-textbook interactions, if left unchanged, will probably not result in meaningful learning. However, if teachers mediate the interaction of students and texts with strategies for meaningful learning, the interaction can be productive. As teachers, we can provide meaningful purposes for reading, we can assist our students to understand the complexities of science prose, and we can provide strategies for metacognition. All of these interventions call upon students to engage in learning from texts at a much high cognition level than has been the case. We should not be surprised if students initially resist our "invitations to think." We should expect that they must think in order to learn meaningfully.

by Sarah L. Ulerick