Teaching Science Inductively- Part I
By David Harriman, historian and philosopher of physics
We gain knowledge by an inductive discovery process. Whether we consider the scientific genius who first made a discovery, or the student who is learning about it, the process is essentially the same. It begins with observations and low-level concepts, and moves by means of experiment and mathematics to higher-level concepts, generalizations and theories. Every logical step of the way, the discoverer must integrate the new evidence within the total context of his knowledge.
Perhaps this sounds obvious. Nevertheless, it took me a long time to understand it. And here is another obvious fact: today, nobody teaches science this way.
It is very challenging to teach science inductively. The curriculum developer must have in-depth knowledge of the historical discovery process, and thus of the factual basis of the relevant concepts and generalizations; he must think of ingenious ways to condense and simplify the enormous range of material; and he must present the material as an integrated whole, continually making connections between current and previous material. Nobody will go to all this trouble unless he is really convinced that it is both necessary and possible. And most people don’t believe either one—that it’s necessary or possible.
First, let’s consider the typical views about whether it is necessary. Today, the majority of educators believe that they can simply tell young students about the advanced conclusions of scientists, and if the students can repeat back what they have been told then they must understand it.
For example, first-graders are told about the correct theory of the solar system. They have a model in their classroom with the big fixed sun in the center and all the little planets—including Earth—revolving around at various distances from it. They learn the names and the order of the little balls that go around the big ball, and then they supposedly understand the solar system.
Now, imagine that I replace the correct model of the solar system with a different model depicting Ptolemy’s geocentric theory. The big Earth would be stationary in the center, and the moon, sun and planets would go around it. The model could be constructed so that each planet revolves in a smaller epicycle while orbiting the Earth in a bigger circle. The students could memorize this model as well as they memorized the other one. Would they believe this geocentric model? Yes, of course; they would believe it for the same reason that they believe the heliocentric model—because the teacher told them so. Since they are never presented with the observational evidence and the reasoning, they have no choice but to passively accept the ideas on the basis of authority.
Here’s another example: If you pick up an elementary school textbook and turn to the chapter on matter, you are told on the first page that matter is made of atoms, and you see a drawing of a nucleus with electrons swirling around it. The students look at the drawing and then they supposedly understand the atomic theory of matter.
This approach to teaching science reminds me of an old movie called Time Bandits. There is a scene where the Devil is explaining how God did everything backwards and botched the whole creation process. God wasted his time creating things like worms and snails. The Devil says he would have done things very differently, and then he gives an example. He shouts out: “If I had been in charge of creation: Eight o’clock, Day 1—Lasers!” This is essentially how science is taught today. Maybe they don’t cover lasers until Day 2, but you get the idea.
And I hope you see that such an education is empty. It is just passive memorization of disconnected ideas, with no real understanding of content and no insight into method. As a result, most students are bored by science and they drop out as soon as the classes become optional in high school. We live in the wealthiest and most technologically advanced country, and we spend more money on education than any other country. Yet studies have shown that the United States rates below some third-world countries in science education. This is not just embarrassing; on the surface, it seems to be bizarre.
But there’s no mystery here. Science is currently taught by a superficial, authority-based method, where the laws are just stated out of context as “thunderbolts from the blue.” It is interesting to note that the progressive educators, who give lip-service to method, are every bit as guilty in this regard as the old classical educators. To the extent that the progressives teach content, they present it as dogma that comes from nowhere and must simply be accepted on the basis of consensus. They are forced into this position because don’t understand or accept the logic of the inductive discovery process.
This raises the issue that I mentioned earlier: many educators have been influenced by the idea that it isn’t possible to teach science inductively, because there is no logic to the discovery process. Scientists just make guesses and sometimes they seem to get lucky. So what else can the teacher do other than present the guesses that have been accepted by the majority of scientists?
But there is an inductive logic of discovery. And the way to make science intelligible and fascinating is to present the discovery process—that is, to guide students on that logical path that leads from observation to theory. Then science becomes a detective story, and the students themselves raise the questions before they get the answers. By following the logic, sometimes the students are even able to anticipate the answers. When I teach science by this method, sometimes the students grasp the implications of the evidence they had already seen and beat me to the next major discovery. When I was explaining the experimental discoveries in chemistry that led to the atomic theory, one student anticipated Avogadro’s law by asking: “Don’t these results imply that equal volumes of gases have the same number of molecules?” And when I was teaching electricity and magnetism, one student anticipated Ampere’s next discovery by asking: “Don’t these results imply that two electric currents should exert a force on each other?” When a student grasps the law himself, and he has the full context to recognize why the law is important, then he doesn’t need to memorize it for a test. He understands it, and he has that understanding for the rest of his life.
For a teacher, this is the ultimate reward -- those “Eureka!” moments where the student makes the connection and grasps why it is so important. But such moments don’t happen unless the material is taught inductively. When the child is merely shown a model of the solar system or a drawing of atomic structure, he has no way to connect the model or the drawing to observations of the world. There is nothing he can do except shrug and say: “Well, okay, if you say so.” That is not a “Eureka!” moment.
Notice that the inductive approach offers one solution to all the problems that plague science education. Do you want the student to have a real understanding of the ideas, and not just floating abstractions? Teach the discovery process—and the student will get all the essential facts that the abstractions are based on and refer to. Do you want the student to gain a deep understanding of method, and not just memorize the content? Teach the discovery process—that is the method. Do you want the student to be excited about the subject? Teach the discovery process—and the student will have the context that makes the material fascinating, and he will see science as a story in which brilliant minds such as Galileo, Newton, Lavoisier, and Darwin are the heroes.