How To Teach Your Child: How To Teach Science (Part 4 of 4)

The science curriculum for the elementary students at VanDamme Academy is taught primarily through experiments. These students are learning principles that are very close to the perceptual level, so we always demonstrate the principle in carefully designed hands-on experiments, so that they see it for themselves.

Let me give you a few examples of this approach from science lessons I taught when I was a homeschooler. My class spent several weeks studying simple machines. Simple machines were discovered very early in history, and the principles behind them are not difficult to grasp. In one class, we studied friction and the effects of friction on motion. We dragged a brick across a board with a spring scale and measured the amount of force it took. Then we placed waxed paper over the board and dragged the brick across the wax paper, again observing how much force was necessary. We did many other related experiments, learning, for example, about lubricants and their ability to reduce friction.

I was always very careful to isolate the principle being studied, so that the hands-on activity did not degenerate into a pointless game. The students were required to write up the experiment, to explain the principle behind it, and to identify examples of the principle from their own day-to-day experience.

If students have a clear, first-hand grasp of the material, finding examples in everyday life is easy and exciting. Two of my students spent a car ride identifying all the simple machines they could find. “This knob on the radio is a wheel and axle, this handle to recline the seat is a lever . . .” and so on.

Here is another example of the lessons I would give to students of this age. We studied air pressure, the existence of which is easy to identify with some simple experiments. In one experiment, we placed a piece of paper over a ruler on a flat table, with the end of the ruler extending over the edge of the table. Then we pressed on the ruler, and felt a great deal of resistance, because there was air pressure from the top holding the paper down, but none from underneath to counteract the pressure from above. Then we put things under the paper to hold it up, so that it was not flat against the table, and pushed on the ruler again. This time, very little force was necessary to lift the paper, because there was air pressure from both sides.

A student taught in such a way will have a solid, independent understanding of the principle. One important consequence and reward of this is that he will be able to integrate what he learns with other things he knows and learns; he will notice its relation to other facts about the world, thus contributing to his ever-growing network of knowledge. If, by contrast, a student cannot grasp a principle first hand, he cannot see its connection to anything else–and his “knowledge” will take the form of disparate bolts from the blue, disconnected from each other and from reality.

Let me give you an example of an integration made by one of my students. We had just finished a series of air pressure experiments, and I came into class one day with a plunger and a step stool. I wet the rim of the plunger, pushed it on the step stool, and lifted the step stool in the air. I asked my students, “Why did that happen?” They thought for a minute, and then one explained that the plunger stuck to the stool because of air pressure. He explained that I had forced air out of the cup, so there was air pressure from the outside holding it on to the step stool, but little from inside pushing them apart. Then I asked, “Why did I wet the rim, of the plunger?” One of my students, thinking back to our unit on simple machines, raised his hand and said the following, “The water works like a lubricant, filling in the bumps and crevices on the surface of the plunger. So wetting the rim of the plunger helps to keep air from getting inside the plunger cup.” Such independent connections and observations can come only from real understanding. If taught in this way, children become enthusiastic about science.

One day, I taught my students the principle that water pressure increases only with depth. I gave them a powerful demonstration by poking holes at the same depth in two vessels of dramatically different diameters, and observing identical jets of water coming out of the holes. They were shocked and fascinated, and when one student’s mother came to pick him up, he immediately went to the board and started drawing diagrams and testing her about this principle to see if she understood it as well as he did. Such enthusiasm springs from a first-hand grasp of relevant principles, which can be achieved only by means of a hierarchy-driven curriculum.

The principle of hierarchy is just as crucial in teaching more abstract scientific knowledge to older children as it is in teaching the simplest scientific knowledge to younger children. Consider the subject of physics.

Most science teachers present the highly abstract laws of physics as if they are self-contained truths, unrelated to the long history of scientific development. For example, Newton’s discovery of universal gravitation, one of the most extraordinary discoveries in the history of thought, is usually presented as an out-of-context commandment to be memorized–as knowledge that, along with Newton’s apple, fell from the sky.

A proper science teacher, by contrast, recognizes what the students must know for this law to be intelligible. He explains the steps in Newton’s reasoning, and ensures that the students have already learned the discoveries leading up to Newton’s theory, the principles they must know if they are to follow his reasoning.

In the famous incident with the apple, Newton asked himself if the same attractive force from the Earth caused both the apple’s descent and the moon’s orbit. In order to check the idea, Newton needed to know the acceleration of the apple (which he learned from Galileo), the size of the Earth (which had been measured by Eratosthenes), and the distance to the moon (which was calculated by Aristarchus). If the students are to grasp the law at hand, they must first grasp these facts–as did Newton.

Further, in arriving at this hypothesis, Newton was relying on Galileo’s principle of inertia, Kepler’s laws of planetary motion, and the law of circular acceleration (which Newton himself had discovered a few months earlier). Without this knowledge, Newton could not even have raised the question. Therefore, without this knowledge, the students cannot grasp the question and they certainly cannot understand Newton’s final answer.

Having been taught physics as it progressed historically, the students at VanDamme Academy know the discoveries of Aristarchus, Eratosthenes, Kepler, and Galileo. When guided through the ingenious process by which Newton integrated this knowledge and built upon it, the students thoroughly grasp the principle of universal gravitation: They see that it is true and why it must be true. The law of gravitation is, in their own minds, connected to reality. It is real knowledge.

Does the hierarchical approach to teaching science require that students be taught the entire history of science, including every detail of every experiment ever performed? No. A crucial part of teaching in accordance with the principle of hierarchy is to select only the essentials. This is in contrast to the common view, expressed in a local newspaper by a high school biology teacher, that the hardest part of his job is keeping up with all the latest discoveries in his field. The latest developments in biology are properly the concern of Ph.D. biologists who have the context to understand them and the need to apply them.

High school students should be taught a carefully selected list of the most essential discoveries in the field, and should be taught them in hierarchical order. Only if they are taught by this method will they emerge with a sound understanding of the fundamental concepts of science and a genuine ability to think. Anything else deprives them of independently grasped, real knowledge, in favor of passively accepted pseudo-knowledge.

The entire field of science education needs to be reconceived–reconceived with respect for the hierarchy of knowledge.