The study of science as an intellectual and social endeavor—the application of human intelligence to figuring out how the world works—should have a prominent place in any curriculum that has science literacy as one of its aims. Consider the following:

• When people know how scientists go about their work and reach scientific conclusions, and what the limitations of such conclusions are, they are more likely to react thoughtfully to scientific claims and less likely to reject them out of hand or accept them uncritically.

• Once people gain a good sense of how science operates—along with a basic inventory of key science concepts as a basis for learning more later—they can follow the science adventure story as it plays out during their lifetimes.

• The images that many people have of science and how it works are often distorted. The myths and stereotypes that young people have about science are not dispelled when science teaching focuses narrowly on the laws, concepts, and theories of science. Hence, the study of science as a way of knowing needs to be made explicit in the curriculum.

Acquiring scientific knowledge about how the world works does not necessarily lead to an understanding of how science itself works, and neither does knowledge of the philosophy and sociology of science alone lead to a scientific understanding of the world. The challenge for educators is to weave these different aspects of science together so that they reinforce one another.

For students in the early grades, the emphasis should overwhelmingly be on gaining experience with natural and social phenomena and on enjoying science. Abstractions of all kinds can gradually make their appearance as students mature and develop an ability to handle explanations that are complex and abstract. This phasing-in certainly applies to generalizations about the scientific world view, scientific inquiry, and the scientific enterprise.

That does not mean, however, that abstraction should be ignored altogether in the early grades. By gaining lots of experience doing science, becoming more sophisticated in conducting investigations, and explaining their findings, students will accumulate a set of concrete experiences on which they can draw to reflect on the process. At the same time, conclusions presented to students (in books and in class) about how scientists explain phenomena should gradually be augmented by information on how the science community arrived at those conclusions. Indeed, as students move through school, they should be encouraged to ask over and over, "How do we know that's true?"

History provides another avenue to the understanding of how science works, which is one of the chief reasons why a chapter on historical perspectives is included in both Science for All Americans and Benchmarks. Although that chapter emphasizes the great advances in science, it is equally important that students should come to realize that much of the growth of science and technology has resulted from the gradual accumulation of knowledge over many centuries.

This realization runs counter to widely held misconceptions about scientific progress. What has been called normal science, in contrast to scientific revolutions, is what goes on most of the time, engages most of the people, and yields most of the advances. While "breakthroughs" and "revolutions" attract people's attention more than step-by-step growth, focusing on those rare events exclusively will give students a distorted idea of science, in that both incremental growth and occasional radical shifts are part of the story of science.

For the same reason, not all of the historical emphasis should be placed on the lives of great scientists, those relatively few figures who, owing to genius and opportunity and good fortune, are best known. Students should learn that all sorts of people, indeed, people like themselves, have done and continue to do science.

To gain this understanding, students will need appropriate learning materials. Historical case studies, backed up by a solid collection of biographies and other reference works and films, will be essential. Also, science and history textbooks will need to be modified to include the history of science. Beginning with science, mathematics, and technology in the early Egyptian, Greek, Chinese, and Arabic cultures, these materials should extend to modern times and include information on the contributions of men and women from every part of the world.

A scientific world view is not something that working scientists spend a lot of time discussing. They just do science. But underlying their work are several beliefs that are not always held by nonscientists. One is that by working together over time, people can in fact figure out how the world works. Another is that the universe is a unified system and knowledge gained from studying one part of it can often be applied to other parts. Still another is that knowledge is both stable and subject to change.

Little is gained by presenting these beliefs to students as dogma. For one thing, such beliefs are subtle. The first one cited above says only that scientists believe that the world can be understood, not that it ever will be so completely understood that science can shut down once and for all, the job done. Indeed, in finding answers to one set of questions about how the world works, scientists inevitably unearth new questions, so the quest will likely continue as long as human curiosity survives. Also, the human capacity for generating trustworthy knowledge about nature has limits. Scientific investigations often fail to find convincing answers to the questions they pursue. The claim that science will find answers always carries the implied disclaimers, "in many cases" and "in the very long run."

The belief that knowledge gained by studying one part of the universe can be applied to other parts is often confirmed but turns out to be true only part of the time. It happens, for example, that the behavior of a given organism is sometimes different when observed in a laboratory instead of its natural environment. Thus, a belief in the unity of the universe does not eliminate the need to show how far the findings in one situation can be extended.

The notion that scientific knowledge is always subject to modification can be difficult for students to grasp. It seems to oppose the certainty and truth popularly accorded to science, and runs counter to the yearning for certainty that is characteristic of most cultures, perhaps especially so among youth. Moreover, the picture of change in science is not simple. As new questions arise, new theories are proposed, new instruments are invented, and new techniques are developed. In response, new experiments are conducted, new specimens collected, new observations made, and new analyses performed. Some of the findings challenge existing theories, leading to their modification or to the invention, on very rare occasions, of entirely new theories—which, in turn, leads to new experiments, new observations...and so on.

But that ferment of change occurs mostly at the cutting edge of research. In fact, it is important not to overdo the "science always changes" theme, since the main body of scientific knowledge is very stable and grows by being corrected slowly and having its boundaries extended gradually. Scientists themselves accept the notion that scientific knowledge is always open to improvement and can never be declared absolutely certain.

From their very first day in school, students should be actively engaged in learning to view the world scientifically. That means encouraging them to ask questions about nature and to seek answers, collect things, count and measure things, make qualitative observations, organize collections and observations, discuss findings, etc. Getting into the spirit of science and liking science are what count most. Awareness of the scientific world view can come later.

Anticipating an eventual understanding of the scientific world view, these early science experiences can be designed to bring out one aspect of the belief in the unity of nature: consistency. Students should sometimes repeat observations and investigations in the classroom, and then, when possible, do so again in the school yard and at home. For instance, students could be asked to compare what happens in different places when an egg is cooked, or how moving objects are affected when pushed or pulled, or what a seed looks like when it starts to grow. These activities should serve to stimulate curiosity and engage students in taking an interest in their environment and the workings of nature.

As children continue to investigate the world, the consistency premise can be strengthened by putting more emphasis on explaining inconsistency. When students observe differences in the way things behave or get different results in repeated investigations, they should suspect that something differs from trial to trial and try to find out what. Sometimes the difference results from methods, sometimes from the way the world is. The point is that different findings can lead to interesting new questions to be investigated.

This emphasis on scientific engagement calls for frequent hands-on activities. But that is not to say that students must, or even can, "discover" everything by direct experience. Stories about people making discoveries and inventions can be used to illustrate the kinds of convictions about the world and what can be learned from it that are shared by the varied people who do science.

Most early adolescents have a more immediate interest in nature than in the philosophy of science. They should continue to be engaged in doing science and encouraged to reflect on the science they are engaged in, with the assumption that they will later acquire a more mature reflection on science as a world view.

Early adolescence, however, is not too early to begin to deal with the question of the durability of scientific knowledge, and particularly its susceptibility to change. Both incremental changes and more radical changes in scientific knowledge should be taken up. Radical changes in science sometimes result from the appearance of new information, and sometimes from the invention of better theories (for example, germ theory and geologic time, as discussed in Chapter 10: Historical Perspectives).

Aspects of the scientific world view can be illustrated in the upper grades both by the study of historical episodes in science and by reflecting on developments in current science. Case studies provide opportunities to examine such matters as the theoretical and practical limitations of science, the differences in the character of the knowledge the different sciences generate, and the tension between the certainty of accepted science and the breakthroughs that upset this certainty.

Scientific inquiry is more complex than popular conceptions would have it. It is, for instance, a more subtle and demanding process than the naive idea of "making a great many careful observations and then organizing them." It is far more flexible than the rigid sequence of steps commonly depicted in textbooks as "the scientific method." It is much more than just "doing experiments," and it is not confined to laboratories. More imagination and inventiveness are involved in scientific inquiry than many people realize, yet sooner or later strict logic and empirical evidence must have their day. Individual investigators working alone sometimes make great discoveries, but the steady advancement of science depends on the enterprise as a whole. And so on.

If students themselves participate in scientific investigations that progressively approximate good science, then the picture they come away with will likely be reasonably accurate. But that will require recasting typical school laboratory work. The usual high-school science "experiment" is unlike the real thing: The question to be investigated is decided by the teacher, not the investigators; what apparatus to use, what data to collect, and how to organize the data are also decided by the teacher (or the lab manual); time is not made available for repetitions or, when things are not working out, for revising the experiment; the results are not presented to other investigators for criticism; and, to top it off, the correct answer is known ahead of time.

Of course, the student laboratory can be designed to help students learn about the nature of scientific inquiry. As a first step, it would help simply to reduce the number of experiments undertaken (making time available to probe questions more deeply) and eliminate many of their mechanical, recipe-following aspects. In making this change, however, it should be kept in mind that well-conceived school laboratory experiences serve other important purposes as well. For example, they provide opportunities for students to become familiar with the phenomena that the science concepts being studied try to account for.

Another, more ambitious step is to introduce some student investigations that more closely approximate sound science. Such investigations should become more ambitious and more sophisticated. Before graduating from high school, students working individually or in teams should design and carry out at least one major investigation. They should frame the question, design the approach, estimate the time and costs involved, calibrate the instruments, conduct trial runs, write a report, and finally, respond to criticism.

Such investigations, whether individual or group, might take weeks or months to conduct. They might happen in and out of school time and be broken up by periods when, for technical reasons, work cannot go forward. But the total time invested will probably be no more than the sum of all those weekly one-period labs that contribute little to student understanding of scientific inquiry.

Students should be actively involved in exploring phenomena that interest them both in and out of class. These investigations should be fun and exciting, opening the door to even more things to explore. An important part of students' exploration is telling others what they see, what they think, and what it makes them wonder about. Children should have lots of time to talk about what they observe and to compare their observations with those of others. A premium should be placed on careful expression, a necessity in science, but students at this level should not be expected to come up with scientifically accurate explanations for their observations. Theory can wait.

Children's strategies for finding out more and more about their surroundings improve as they gain experience in conducting simple investigations of their own and working in small groups. They should be encouraged to observe more and more carefully, measure things with increasing accuracy (where the nature of the investigations involves measurement), record data clearly in logs and journals, and communicate their results in charts and simple graphs as well as in prose. Time should be provided to let students run enough trials to be confident of their results. Investigations should often be followed up with presentations to the entire class to emphasize the importance of clear communication in science. Class discussions of the procedures and findings can provide the beginnings of scientific argument and debate.

Students' investigations at this level can be expected to bear on detecting the similarities and differences among the things they collect and examine. They should come to see that in trying to identify and explain likenesses and differences, they are doing what goes on in science all the time. What students may find most puzzling is when there are differences in the results they obtain in repeated investigations at different times or in different places, or when different groups of students get different results doing supposedly the same experiment. That, too, happens to scientists, sometimes because of the methods or materials used, but sometimes because the thing being studied actually varies.

Research studies suggest that there are some limits on what to expect at this level of student intellectual development. One limit is that the design of carefully controlled experiments is still beyond most students in the middle grades. Others are that such students confuse theory (explanation) with evidence for it and that they have difficulty making logical inferences. However, the studies say more about what students at this level do not learn in today's schools than about what they might possibly learn if instruction were more effective.

In any case, some children will be ready to offer explanations for why things happen the way they do. They should be encouraged to "check what you think against what you see." As explanations take on more and more importance, teachers must insist that students pay attention to the explanations of others and remain open to new ideas. This is an appropriate time to introduce the notion that in science it is legitimate to offer different explanations for the same set of observations, although this notion is apparently difficult for many youngsters to comprehend.

At this level, students need to become more systematic and sophisticated in conducting their investigations, some of which may last for weeks or more. That means closing in on an understanding of what constitutes a good experiment. The concept of controlling variables is straightforward but achieving it in practice is difficult. Students can make some headway, however, by participating in enough experimental investigations (not to the exclusion, of course, of other kinds of investigations) and explicitly discussing how explanation relates to experimental design.

Student investigations ought to constitute a significant part—but only a part—of the total science experience. Systematic learning of science concepts must also have a place in the curriculum, for it is not possible for students to discover all the concepts they need to learn, or to observe all of the phenomena they need to encounter, solely through their own laboratory investigations. And even though the main purpose of student investigations is to help students learn how science works, it is important to back up such experience with selected readings. This level is a good time to introduce stories (true and fictional) of scientists making discoveries—not just world-famous scientists, but scientists of very different backgrounds, ages, cultures, places, and times.

Students' ability to deal with abstractions and hypothetical cases improves in high school. Now the unfinished and tentative nature of science may make some sense to them. Students should not be allowed to conclude, however, that the mutability of science permits any belief about the world to be considered as good as any other belief. Theories compete for acceptance, but the only serious competitors are those theories that are backed by valid evidence and logical arguments.

The nature and importance of prediction in science can also be taken up at this level. Coverage of this topic should emphasize the use of statistics, probability, and modeling in making scientific predictions about complex phenomena often found in biological, meteorological, and social systems. Care also should be taken to dissociate the study of scientific prediction from the general public's notions about astrology and guessing the outcomes of sports events.

Scientific activity is one of the main features of the contemporary world and distinguishes present times from earlier periods. As an endeavor for learning how the world works, it provides a living for a very large number of people. It is important for students to understand how science is organized because, as adults in a democracy, they will be in a position to influence what public support will be provided for basic and applied science. Students also need to be exposed to four other aspects of the scientific enterprise: its social structure, its discipline and institutional identification, its ethics, and the role of scientists in public affairs. These matters do not require explicit discussion in the early grades but should appear more and more frequently as students progress through school. By the time they graduate, students should feel comfortable talking in general terms about the nature of the scientific enterprise and should be able to understand discussions of science issues in the news.

Science should begin in kindergarten with students learning to work in small teams (rather than as isolated individuals) to ask and answer questions about their surroundings and to share their findings with classmates. Teachers and older students can help the groups learn how to share in deciding what to do, in collecting and organizing information, and in making presentations.

From the start, teachers should foster scientific values by recognizing instances of them in the work of individual students and student groups. For example, praise should be given for curiosity and creativity even when the investigations they lead to do not turn out as planned.

Given the value that science places on independent thought, it is important that students be assured that although they are part of a team, they are free to reach different conclusions from their classmates, and that when they do they should say so and say why. Because youngsters want to be liked, this notion that one can disagree with friends and still be friends is not easy to accept (and may not be true in the short run) and therefore has to be approached judiciously.

Student investigations usually involve collecting live animals to bring into the classroom for observation. Although most children want pet-like animals (goldfish, rabbits, etc.) to be treated carefully, not all do, and some children can be cruel. The use of animals in scientific research is a very complex issue, but long before students are ready to discuss it in any depth, they should have opportunities, in the context of science, to interact with living things in ways that promote respect. Teachers should all be familiar with the National Science Teachers Association's guidelines for responsible use of animals in the classroom, published in the association's handbook.

The history of science and technology is mostly too advanced a subject for students in the earliest grades. But they are not too young to learn from their own collective experience that everyone can find some things out about nature, just as everyone can learn numbers, the alphabet, and how to read.

As student research teams become more adept at doing science, more emphasis should be placed on how to communicate findings. As students learn to describe their procedures with enough detail to enable others to replicate them, make greater use of tables and graphs to summarize and interpret data, and submit their work to the criticism of others, they should understand that they are engaged in the scientific way of doing research.

Career information can be introduced to acquaint students with science as an occupation in which there is a wide variety of different kinds and levels of work. Films, books (science adventure, biographies), visits by scientists, and visits (if possible) to science centers and to university, industrial, and government laboratories provide multiple opportunities for students to become informed.

Teachers should emphasize the diversity to be found in the scientific community: different kinds of people (in terms of race, sex, age, nationality) pursuing different sciences and working in different places (from isolated field sites to labs to offices). Students can learn that some scientists and engineers use huge instruments (e.g., particle accelerators or telescopes), and others use only notebooks and pencils. And most of all, students can begin to realize that doing science involves more than "scientists," and that many different occupations are part of the scientific enterprise.

Teachers should continue to seize opportunities for introducing information on science as a diverse line of work. Above all, children in early adolescence need to see science and science-related careers as a real option for themselves personally. That does not imply heavy, possibly premature recruiting, but means broadening student awareness of the possibilities and helping all students to keep themselves eligible for these possibilities. If such awareness develops in a proper context, then the knowledge gained will be valuable to all students when they become adult citizens, regardless of vocation.

By this level, student investigations should be more professional than could reasonably be expected in the elementary grades. For one thing, students must assess the risks associated with an investigation before being given permission to proceed. For another, students should now be using computers as scientists use them—namely to collect, store, and retrieve data, to help in data analysis, to prepare tables and graphs, and to write summary reports. If possible, students should have the opportunity to work on investigations in which they can use computers to communicate with students elsewhere who are working on the same problems.

At this level, science and history can support each other more elaborately. As students study science and mathematics, they should encounter some of the historical and cultural roots of the concepts they are learning. As they study the history of the different periods, cultures, and episodes, students should find that science, mathematics, and invention often played a central role.

Studies in history, government, and science can also come together to help students understand science as a social enterprise. Seminars based on actual case studies provide a way to approach issues of ethics in science and the role of scientists in social decision-making. There is no shortage of current issues, ranging from citizen resistance to potentially dangerous research in the community, to the use of human prisoners or animals in medical experiments, to charges of scientific fraud. Newspapers and magazines, the "news and comment" and "letters to the editor" sections of science journals, and congressional testimony all provide easily accessible documentary material. A seminar format can focus on informed discussion and debate rather than covering predetermined material to reach predetermined conclusions.

No matter how the curriculum is organized, it should provide students with opportunities to become aware of the great range of scientific disciplines that exist. There is no sense, however, in having students memorize definitions of anthropology, astrophysics, biochemistry, paleobacteriology, and the rest of the family. Individual students or small groups of students can study different disciplines in some detail—most scientific societies are happy to help out—and then share their findings with one another. The focus of such studies should be substantive (what are typical studies like in the discipline) and sociological (how is the field organized and who is in it), and they should probably involve, over an extended time, interviews, field trips, readings, data analysis, and, if possible, the conduct of small-scale experiments or field studies. Such activities will contribute to science literacy goals, and they should also help students realize how many different career possibilities exist in science.