Monday, March 29, 2010

Teaching Physics To Kids (And Dogs)

For the longest time, I resisted myself from making any comments on this. I respect other physicists who spend time and effort trying to educate the public on various aspects of physics. It isn't easy, not just because of the nature of the subject, but because we have to be very careful on what we say and how we say certain things. This is because we can mean one thing when we say it, but the public may understand things in a very different way because of the different "vocabulary" that we some time use. So trying to explain something, or writing a book, on physics is an endeavor that requires a lot of self-exploration and self-evaluation.

I've read a bit of Chad Orzel's book "How to Teach Physics to Your Dog", and I've read many reviews about it. It's a fun book, and I highly recommend it. However, I am a bit uncomfortable with the title of the book, and I will try to explain it here. I only hope the reasons don't become confusing and I end up sounding as if I'm criticizing the book, which is far from my intention.

What do we mean when we try to teach someone something? If I tell you that Newton's 2nd Law says "F=ma", have I taught you anything? If tell you that the largest planet in the solar system is Jupiter, have I taught you anything? To me, teaching means the imparting of knowledge, not simply the imparting of information. There's a difference there. Information can be a series of disconnected, disjointed items, whereas a knowledge is not just information, but how these items connect to each other. In other words, you know not only that "F=ma", but you know what it means, and how to use it. This isn't automatic. Many people know F=ma. In fact, we write it early in our class in intro physics. Yet, give these students a simply projectile problem to do right after you introduce that equation and see how many can use it to solve such a problem. This clearly shows that just because you have that information, it doesn't mean that you have the knowledge of what it is.

So that brings us back to whether you can teach your dog, or your kids, physics. At some level, you can. You can certainly show simple concepts until the kids see a pattern, and they now understand how something behaves. They might even be able to replicate such a thing with other examples. So yes, that would be teaching. But how do you teach kids (and dogs) quantum mechanics, for example? All the pop-science books meant for the public have done it simply by telling the readers the "weird" properties of QM, how a quantum system behaves, and what possible implication it could mean. But these are nothing more than telling someone a series of information. In fact, when done this way, these series of information, more often than not, appear disjointed and disconnected. People learn about the Schrodinger cat, for example, but do not realize that the same principle (superposition) is what makes quantum entanglement so weird. Without that principle, quantum entanglement is no more strange than the classical case of a simple conservation of (angular) momentum. Or would people realize that the Heisenberg Uncertainty Principle isn't really a "principle", or that it is not separate from the wavefunction itself and how we define what we call "observables"? The HUP is almost always automatically there when we deal with the Schrodinger equation wavefunction.

To me, this is not teaching physics. It is teaching ABOUT physics. There's a difference. There is value in teaching about physics, and many pop-science books do a tremendous service to the field by introducing people to it. But it should not be confused with teaching physics. The latter involves imparting knowledge in such a way that the recipient obtains the ability and skill to use and apply the information. I consider being able to use F=ma and solve kinematical problems as a sign that someone has a knowledge of F=ma. In Mary Boas's "Mathematical Methods in the Physical Science", she stated:

To use mathematics effectively in applications, you need not just knowledge, but skill. Skill can be obtained only through practice. You can obtain a certain superficial knowledge of mathematics by listening to lectures, but you cannot obtain skill this way.

And I would apply that to the difference between information and knowledge, physics and about physics, as used in this context. One needs to clearly differentiate the superficial understanding of something versus learning something. This should be done both by the instructor (or author) and the student (or the reader).

There's plenty of worthiness in a book that teaches physics, and a book that teaches ABOUT physics. One can only hope that a reader does not confuse the two.



Kathy Ceceri said...

I wrote the "Teaching Physics to Kids" post on So I'm curious. At what point are kids learning physics as opposed to learning about it? Specifically, are they learning physics in the typical high school class? And do you think one is more valuable than the other at the high school level?

ZapperZ said...

That's a good question. My guess would be that when they "play", that has more to do with learning physics than learning about physics.

There's a push for the teaching of science to be less classroom based where the kids are being fed a stream of disconnected information, and more on letting them do self-discovery exercises. Finding the exact relationship between two separate quantities, for example, is an excellent exercise. One starts to find how manipulating one, changes the other, and in what way. In other words, at some point, it evolves from being a qualitative description, to a more quantitative understanding of such a relationship.

I'm not sure if they're learning physics in a typical high school class, because I've heard both good stories and bad stories. There are plenty of physics teachers who spend a lot of time doing outside-classroom activities, such as visiting theme parks and tossing pumpkins, all in the hope that what they've been taught in class can translate into something tangible that they can see. This is definitely part of learning physics because one is trying to show how, say, F=ma, can be applied in "real" situations. It isn't just an isolated mathematical equation.