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Saturday, September 29, 2012

Playing with power on a Saturday morning

Many years ago, I went to one of those things where kids get to do interesting and educational things on Saturday mornings. I don't remember exactly how many times this happened or all of the topics which we covered, but a few things have stuck with me all these years.

One day, our topic was basic electricity. They had all of us kids stand in a circle and hold hands, and then the ones at either end touched something which had been set up for the demonstration. The resulting slight tingling shock was enough to show us just what a circuit could be.

We also did the usual thing with a short length of PVC pipe and different kinds of fabric where you build up a static charge and then apply it to other things. We'd fool around with charging up balloons and making our hair jump out to meet it, and they also showed us what happens when you hold something sufficiently charged near water coming out of a faucet. If you've somehow never tried this, you should. It's trippy.

Finally, there was one more part which really stuck with me. All of us were given a small set of basic things with which we could build a circuit. There was a battery holder and batteries, a small knife switch, and a lamp, plus some sort of wiring to connect it all up. They showed us how to head out from the battery, cross the switch, then cross the lamp and come back into the battery, and then how it would light up.

With this done, we were able to mess around with it and see that you could do things like reverse the switch or lamp and it would still work. You could even reverse the battery since the lamp didn't care which way things were going. As long as it saw the current, you were in business.

I forget exactly how far this went. I'm guessing we probably didn't get as far as series vs. parallel and what sort of effects you get by doubling up your batteries one way or the other. I know I figured out some of that later by myself, probably by sticking a bunch of cells end to end and then wondering why the insulation bubbled off and things started glowing when I completed the circuit with a chunk of wire.

Encountering this stuff so early on means it's not really magic. It's just another thing I fiddled with along with all of the other kids who did that same "enrichment exercise" that morning. It was a bunch of parents and teachers who wanted to add something a little beyond what would normally happen in a classroom. I think they succeeded.