An Educator's Plan For Reforming The Way We Teach Science

Secondary school science courses in the United States have become major filters to careers in science or science-related fields. With the recent imposition by almost all states of increases in science requirements for graduation from high school, secondary school science courses unfortunately have gained the ad- ditional reputation of contributing to the already high dropout rates that occur between grades 9 and 12. (Recent announcements by the Department of Education reveal that these rates are still increasing.) A careful analysis of the existing scope, sequence, and coordination of science subject matter in U.S. secondary schools reveals very serious deficiencies. However, certain reforms, if implemented soon, would produce increases in the number of children who study science and, ultimately, the number of persons entering scientific and engineering careers (at present, these young people account for about 5 percent of all students). The proportions of underrepresented groups in these careers would also increase. At the same time, the remaining 95 percent who do not pursue such careers would become sufficiently literate in science to participate effectively in our scientific and technological world. The necessary reforms involve developing an educational model that will bring a larger population into science careers, thus "broadening the pool" rather than "skimming the cream." Under the present model, the sequencing of courses and tracking of students reinforce an accumulation of advantage for some students while effectively precluding others from later selecting science as a career. For example, a child who has not enrolled in algebra in grades 8 or 9, and for that reason is not able to take other more advanced math courses in sequence, is not ready for the series of science courses offered in high school. As a result, such a student is ruled out from majoring in the sciences or engineering fields in college. Moreover, high school physics, chemistry, and biology courses duplicate substantial portions of introductory college courses. Young people who take these high school courses enter college with prior knowledge of the subjects, and they also score higher on entrance exams. They therefore are perceived as having greater ability. They are then given scholarships and opportunities to study under the best faculty, with the result that their prior advantages are rewarded, leading them to continue in these science fields. On the other hand, young people who did not take these courses in high school, but later show interest, are at such a disadvantage that without special assistance or extraordinary motivation and persistence, they will never be able to compete successfully with their more advantaged peers. Since such disadvantage in the physical sciences is often associated with women and minorities, it is not surprising that we find their numbers disproportionately low among engineers and physical scientists. How then can we encourage the child who has not yet achieved significantly in science or math? We know that motivation is well established as a major variable in learning. Prior success strongly affects students' self-esteem and self-image. Many children are led incorrectly to believe that they lack the ability to learn science or math, as they compare their achievements with those of their more experienced and advantaged peers. They avoid studying science and math because they believe with absolute certainty that they lack some special ability to succeed in these subjects. The following analogy, based on molecular motion, may be appropriate to our problems in science teaching. Imagine a container of gas molecules of several kinds moving in all directions at various speeds. Some that move slowly now will, when struck, move much more rapidly. Suppose you want to select the fastest molecules moving in a particular direction. You could place a small opening in the container, and when a fast molecule approaches the opening, push the molecule in the direction you want it to go. In this way you can select the fastest molecules. You would, of course, be ignoring even faster molecules moving in other directions. You would also be ignoring the fact that other molecules will later change speed and may then be moving even more rapidly than the ones you have already selected. The present condition of secondary school science is like this state of the gas. We select the young people who happen at a certain time to be moving fastest in the "right" direction, and we ignore even faster (more able) children who do not happen at that moment to be moving in the "right" direction. We give those selected students the added push (advantage in the form of resources, teacher attention, and recognition), and we ignore the rest. There is another way of increasing the number of fast molecules moving toward the opening. If you heat the entire sample of molecules, all will move faster. The fastest will be even faster than before, and plenty of molecules will pass unaided through the opening. There will be a much greater variety of molecules in the ones passing through. And you've accomplished this without selecting certain molecules and giving them special assistance. Heating the gas is analogous to providing more and better science education for all children so they can all move faster. Many of them will move in the "right" direction, but not necessarily at the time we may want them to do so. If we allow for this delay, we will reap a rich selection of students in science, just as we got a greater variety of molecules in the heated gas. How then do we make secondary school science accessible to all students? We must attack the major cause of disinterest and failure: the way science courses are structured, sequenced, and taught, and the complete lack of coordination among them. The fundamental problems with high school biology, chemistry, physics, and earth and space science courses are that they are not coordinated, they are highly abstract and theoretical, they do not spend enough spaced time on each subject, and they do not use correct pedagogy. In short, we never give students a chance to understand science. As an example, high school physics students are, from the first day, exposed regularly to the highest levels of abstract thinking, and this continues unrelentingly for the next 179 days of the school year. Streams of mathematical symbols are introduced, as various concepts are briefly discussed in words, with no time devoted, or experience provided, for children to assimilate these concepts prior to having them represented by symbols. Then these symbols are set down in complex relationships as derived formulas or empirical laws, and complicated problems are presented for solution using them. Most students simply try to follow some procedure they have memorized, and few understand what they are doing or why. Because all of introductory physics must be concentrated into that one year, the phenomena and descriptive materials are presented, but only very quickly, and they are followed immediately by the abstractions and generalizations. It is very common for the first or second chapters of a physics book to explain the abstract concept of vectors, and only later specify these abstractions to velocity, force, or electric field intensity. Nothing in the students' experiences has prepared them for this pace and level. They have not been given enough time to begin to assimilate even the basic concepts, theories, and applications. By contrast, consider the secondary school-level science program offered in Britain, Europe, the USSR, Japan, and the People's Republic of China, our major competitors either economically or militarily. In most of these countries, all students take several years of biology, chemistry, and physics. And essentially all children learn these subjects successfully. The dropout rates in these countries rarely exceeds 5 percent, compared with our 30 percent. Not only do these countries teach more science to more students, but also they do so to more of those students we call "low ability" or "noncollege-bound." How do they do it? They carefully design the scope and sequence of their science programs and make sure the subjects are well coordinated with one another. Most important, each of the subjects is taught over several years. The secret of success in teaching science for such countries is multifaceted. First, and most important, they offer the subjects over four or five years instead of just one or more of those years. Second, they have tried to sequence the content and approach, starting with the concrete, phenomenological, and descriptive in the early years to the semiquantitative and empirical in the middle years and then to the theoretical and abstract in the later years. When you analyze the content and level of the last year for each of these subjects in these other nations, you find that they are almost identical with what we offer our students. But our students don't have the four or five years of prior grounding in experience and applications. No wonder so few of our students learn the subjects and so many see our courses as hopelessly difficult. I have made such an analysis on the most recent editions of physics textbooks in the USSR. The last of the five-year sequence of physics is at almost exactly the same levels as topics taught to American children in the typical high school physics class. In effect the physics that we cover in one year is spread out over a period of five years in the Soviet schools. In Great Britain, much of Europe, the USSR, and the People's Republic of China, each high school science course includes many practical applications, so that young people understand why they need to learn science. Finally, these countries have attempted to coordinate the content from one subject to another, although this, too, is an area in which they express a desire to make improvements. In one of these countries, for example, during a certain number of class hours in one year, students in biology class explore the human heart and the circulatory system. In chemistry class, they investigate chemical reactions that involve oxygen and, in particular, such metabolic reactions as oxygen transport by hemoglobin. At the same time in physics class they study the kinematics and dynamics of fluid flow. Some would argue that these countries lack breadth in their overall education; that simply is not true. Every child is also required to study government, geography, history, music and art, languages, and shop skills. The latter, which are required every year, are not like our dead-end vocational programs. Shop skills offer students essential experience working with their hands to make, shape, bond, and cut things - skills that give them the option to become an outstanding experimental scientist, a laboratory technician, or a handyperson in their own lives. This broad curriculum is possible simply by extending the school year and the school day. Some may protest that such a system could never work here because we are a nation of 16,000 school districts. But who effectively controls the curriculum now? Not just the 16,000 school districts, but the textbook publishers, who simply react, as they must, to the market. So let's change the market. The publishers will happily respond. Working with school districts, this market can be changed, and publishers are ready to cooperate to improve science education. Let me offer a possible reform model for redesigning our high school science curriculum. This model, first suggested by chemist Marjorie Gardner, former director of the Lawrence Hall of Science at the University of California, Berkeley, includes three years of biology, three years of chemistry, and three years of physics. In our present "layer-cake" system children who enroll in one of these courses attend class every day of the week, for five or six hours per week, for one school year. Then if they take a course the next year, they would do the same for that course. About 60 percent of U.S. children take one year of biology, usually in grade 10, and that is their science. Some 40 percent take biology and chemistry, but no physics. And about 20 percent take all three sciences in high school. In the reformed model I suggest, all children would take all three subjects, but in a totally different way. They would spend three years learning each subject, but not five hours per week in each. In the first year, grade 10, they would spend three hours per week in biology, two hours per week in chemistry, and one hour per week in physics. The coverage during this year would be mainly descriptive and phenomenological, with little or no use of symbols, equations, or similar abstractions. Theories or models would be discussed using only words and nonquantitative techniques. In grade 11, children would spend two hours per week in each of the three sciences. Now they begin to focus attention more on symbolic and quantitative material. They would learn a few empirical laws, like the gas laws in chemistry and Snell's law in physics. Finally, in grade 12, students would spend one hour per week in biology, two hours per week in chemistry, and three hours per week in physics. This would be the year for the abstract and theoretical materials. In biology, there would be an examination of recombinant DNA and genetics. In physics, students would examine wave models, the kinetic molecular theory, and similar mathematical abstractions. In chemistry, they can study orbital and organic chemistry using quantitative methods. This is only one possible model for changing secondary school science curricula. Coordination is essential if these various components are to be learned properly. And, of course, any such broad changes in curricula would pose significant staffing, scheduling, and other problems. But change can come only from exploring what is ideal and possible and then working from there to what is practical. Science need not be the terrible filter that it is now. It need not be an unpleasant experience for so many. Most people are able to learn physics, chemistry, biology, geology, and other related subjects. People can learn how these subjects apply to their lives and to society's problems. If we teach science to all students in a coordinated way from the concrete to the abstract, with practical applications and with enough time for students to assimilate the information, our future citizens will be more evidence-oriented. They will know how and when to ask questions, how to think critically, and to make important decisions based on reason rather than on emotion or superstition. Science made understandable and accessible to all will also mean more and better scientists and engineers - and a different mix among them, including larger numbers of such now underrepresented groups as women and minorities. Bill G. Aldridge is executive director of the National Science Teachers Association in Washington, D.C. This essay is adapted from a recent paper delivered before the New York Academy of Science: "Essential Changes in Secondary School Science: Scope, Sequence, and Coordination."

An Educator's Plan For Reforming The Way We Teach Science

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