ASEE PRISM - Feb 2001

The science books used in the classroom today provide a lot of facts, but they don't help children grasp the most basic concepts about the world we live in.

By Stephen Budiansky

After yet another dismal showing by American students on standardized math and science tests—in the most recent cross-national comparison, American eighth graders did worse than students in Russia, Japan, Korea, Singapore, Canada, and 17 other countries—humor columnist Dave Barry shot back that while it was true that American schoolchildren may not have the highest test scores in the world, they do have the biggest backpacks.

Barry was of course intending a bit of humorous incongruity, but he actually appears to be on to something. Those huge textbooks that our children lug back and forth each day are literally the largest and heaviest of any used in the more than 40 countries whose students were tested. Driven by intentions ranging from earnest and honorable to cynical and commercial, American science textbooks have become larger and flashier, chock full of colorful photographs, diagrams, "activities," "minilabs," sidebars about minorities in science, science in history and literature and art, and current issues such as the use of hormones in dairy cattle.

The only thing the books utterly fail to do, according to scientific and educational experts who have examined them closely, is teach science. A recent study of middle-school science textbooks by Project 2061—a science and mathematics curriculum reform initiative of the American Association for the Advancement of Science—found that not a single one of the books met even the minimum requirements for effectively teaching science. "Our students are lugging home heavy texts full of disconnected facts that neither educate nor motivate them," says George Nelson, a former astronaut who directs Project 2061.

Textbooks have always been an easy target for those out to lambaste the state of public education, and of course many factors are at work in the poor showing of U.S. students in science and math—not least poor teacher preparation. In a study conducted by the National Science Teachers Association, 23 percent of middle school teachers reported they have taught subjects for which they had no prior course work. But Nelson emphasizes that precisely because so many teachers are shaky in their own math and science skills, they rely disproportionately on the texts. And textbooks ought to be the easiest things to fix: "Textbooks are incredibly important. Textbooks are the de facto curriculum in this country," Nelson says.

Back in the immediate post-Sputnik days the major criticism of science texts was that they were out of date and lacking in rigor. In more recent years science texts have become a battleground for special interests, including minority groups, environmentalists, and creationists. Other critics have received much attention lately by compiling lists of factual errors spotted in texts (e.g., the Statue of Liberty is sheathed in copper, not bronze as one textbook states).

Yet these sorts of fights and criticisms, say many experts, distract from the real and much deeper problems with the books. The problem is not that American schoolchildren can't define a kilowatt hour or give the valence number of oxygen; the problem is that they have not grasped the most basic concepts about the world we live in. Tests and studies have shown that students don't understand what matter is, let alone how atoms and molecules explain the properties of matter. They don't understand that air is a substance, or that light travels from one place to another, or what a force is, or what the difference between heat and temperature is; they do not know that plants manufacture their own food from air and water or how traits are inherited and change; they do not know that the earth's physical features are formed by slow processes acting over very long times, or what causes earthquakes.

This problem is vividly demonstrated in a video produced by researchers at the Harvard-Smithsonian Astrophysical Observatory, who sought to understand better how children learn scientific concepts. The researchers filmed fourth graders on the playground and MIT students on graduation day, and asked each to explain where the weight in a tree comes from. A tree starts as a seedling; it ends up as a log; where did all that extra stuff come from? The answers that the MIT students and the fourth graders gave were almost identical, and identically wrong.

Nearly all said the added mass came from sunlight, or from water, or from the soil. When prompted with the correct answer, several of the MIT graduates expressed astonishment at the idea that most of the added weight could have come from carbon dioxide gas in the air, since "this much air wouldn't weigh this much," said one baffled student as she hefted the log. All had been introduced to the idea of photosynthesis, and knew some of the relevant words, but none really had even a basic picture of what matter is, the fact that matter is conserved, or that it can be transformed by chemical reactions.

Just the Facts

One of the major problems reflected in the textbooks, says Nelson, is that "the education community's understanding of science is that it's a heap of facts and vocabulary words." Glencoe Life Science, for example, lists "Science Words" in the margin at the start of each chapter, and many are terms that even a well-educated scientist in another field would probably not know, nor need to know. Saprophyte, Punnett Square, auxism, Islets of Langerhans, commensalism, and taiga are but a few of the terms seventh-grade biology students are asked to master. Macmillan/McGraw-Hill Life Sciences offers up, in its unit on plants, phloem cells, cortex cells, xylem cells, apical meristem, palisade cells, and cambium. The exercises included in each chapter frequently amount to nothing more than regurgitation of these words and definitions.

While the substance of the middle-school texts focuses on such dry facts and terminology, the form the books take borders on the hyperkinetic. They are full of sidebars, boxes, and other presumably eye-catching special features bearing such titles as "Flex Your Brain," "EXPLORE!", "Find Out!", and "Minds On!" The claim is often made that with today's generation of television-reared, short-attention-span children, books need to offer all sorts of bright, short, attention-getting tidbits.

But one teacher's study of how children actually react to these texts found that they were often simply confused by the overload: "Children do not naturally respond to the illustrations, graphics, and highlighted items in text" and actually "need instruction" in how to make sense of these "texts with many features." Some children try to read through a whole page from top to bottom as if it were a "traditional" text and become confused by the sudden jumps into sidebar material and captions; others look at the picture captions but never read the text; some read the text but never read the lesson titles.

The incoherence in the texts occurs at a far deeper level, however, and this goes to the heart of the criticism from the AAAS and other experts. Macmillan/McGraw-Hill's Changes in Matter is one of the least cluttered books, but it, like all of the standard texts, throws a welter of concepts and terms at students in confusing order. It brings in atoms on the first few pages with the didactic and, to most students, probably incomprehensible assertion that "matter consists of atoms of various weights that interact in accordance with specific principles." This is followed by an "Activity!" (weighing inflated and deflated balloons) that does make a nod at demonstrating that air is matter. But then come two pages of "Science in Literature," a "Mind On!" exercise (describe, to an alien who has never seen it before, what ice cream is), a "Multicultural Perspective" tip for the teacher ("Assist students in locating the Dead Sea on a world map"), and then several more pages of didactic assertions about states of matter. The text flits rapidly from one topic to the next—atoms and electrons and the periodic table and acids and bases—nowhere really even attempting to relate the molecular structure of matter to its observable properties.

One of the key findings of Michigan State University researchers who developed an experimental middle-school science curriculum was the importance of leading students through a logical chain of evidence, of showing them a variety of phenomena that can be explained by the same basic principle, and of providing students with a chance to put to use the ideas they have learned. This is crucial in breaking down students' preexisting misconceptions—which are often deeply held and based on intuitive but naive beliefs about the world. It is also essential to making the insights stick. And it is also how science actually works: Science is not just facts to be memorized or terms to learn, but a process for building up a picture and explanation of the world from evidence.

Most children, for example, find it hard to accept the notion that air is matter; common sense says it is not, for it cannot be felt. Most children also believe that solids weigh more than liquids; again, in everyday experience they usually do. In the test curriculum that the Michigan researchers developed on matters and molecules, the unit begins with a series of experiments and demonstrations to convince students that one substance—water—can be a solid, liquid, or gas, and that gases, even though they are often invisible, have weight and really are matter. In one experiment, students weigh an ice cube in a ziplock bag, then let it melt and weigh it again. In another the teacher boils water in a flask, the top of which is connected to a glass tube that leads to another flask; the students can see the water disappear from the first flask and reappear in the second, even though no visible substance is passing through the tube. These hands-on exercises are simple, but vivid and to the point.

Why Things Are

There are several forces at work to make science textbooks this way, and make it so hard to change. Judy Platt, spokesperson for the Association of American Publishers in Washington, argues that the textbook publishers are merely responding to requirements set by the states. (McGraw-Hill, Addison Wesley, and Prentice Hall were all asked to comment for this article and declined to respond. Pearson PLC, which owns the latter two, referred inquiries to the Association of American Publishers.) The AAAS experts say the problem is more complex, and that one thing that sells teachers on particular books is not their substance, but all of the accessories that come with them. Along with the teacher's edition comes a whole crate full of ready-made lesson plans, transparencies, handouts, posters, videos, CD-ROMs, audio tapes, activity cards, and banks of test questions. Jo Ellen Roseman of Project 2061 says, "Our reviewers went through all of this material and can say authoritatively: It's not worth it. But we're told that teachers expect those things with the books."

But the publishers are certainly correct that the states are pushing them to do one thing that is a source of inherent weakness in most of the books: to cover a lot of ground. This has been exacerbated by the current movement among many states to create rigorous standards of learning. Yet state standards tend to be framed in terms of quite specific facts to be mastered ("the student will understand that all matter is made up of atoms . . . atoms are made up of electrons, protons, and neutrons . . . matter has physical and chemical properties that can undergo change"); the easiest way to satisfy everyone is to produce a textbook that simply rattles off these required facts. There just isn't time or space to develop them properly in a way so that students actually grasp them. The result is textbooks that are, as Project 2061 noted, "overstuffed but undernourished," covering two or three times as many topics as the AAAS believes they should.

By contrast, a curriculum such as the "Matter and Molecules" unit developed by Michigan State is narrow, focused, and unflashy. "Matter and Molecules" exists as a loose-leaf collection of black and white photocopied sheets. It does not use a lot of terminology; it does not have any references to current controversies like global warming; it does not have boxes about "Careers in Science" or multicultural connections. It does, however, expect students to learn what matter is and how atoms and molecules explain the properties that matter has. It does one simple thing no standard textbook does—lay out in simple, clear language for the teacher what the goals are of each unit, what misconceptions students are likely to bring, and how those misconceptions need to be systematically addressed. It ties the material not in great sweeping waves of the arms to history, current events, art, literature, and multiculturalism, but rather to everyday phenomena that children can experience—what happens to the air that's pumped into a bicycle tire and where the water goes when wet clothes dry on a line.

Roseman says that the research that has been done, by the Michigan group and others, has shown again and again that such "vivid" examples are the key to learning. When the experimental Michigan curriculum on matter and molecules was tried in several new schools, the percentage of students who mastered the material went from 25 percent to 50 percent.

At 69 pages and weighing less than a pound, "Matter and Molecules" also probably induced far fewer back problems.

Stephen Budiansky is a freelance writing living in rural Virginia.