Experimental Physics

The former right-back of Torpedo Entenhausen is trying to learn physics, and has hired me for private tuition. He is paying me in food, which suits us both fine.

His physics course sounds very boring. He sits through long lectures, and then sits in problem groups where the tutor solves the problem on the blackboard. After hours of tuition, he has done nothing himself, and learnt almost nothing. He has a full set of notes, but it would have been far cheaper and easier just to photocopy them all.

Over the past few years I have developed a very experimental view of physics. Physics should start with an experiment and end with an experiment. It is impossible to understand a physical property unless you can relate it to an experiment. His course doesn't seem to do experiments. Maybe it costs money, and takes too much effort. It is cheap and easy to write P=m*v, but expensive to find a cannon and a place to shoot it. The exam questions are full of mathematical detail, of vectors, equations and calculations, and of units. But they never ask "How do we know this?" or "How could you test this law?".

So yesterday, after a bout of mathematical problem solving, I tried to change matters. We did the following experiments, first in his garden, then in a children's playground:

1/ Vitamin pill rocket, as a demonstration of the conservation of momentum You put a fizzy pill in the lid of a tube of vitamin pills, and fill the tube 1/3 full of water. Reattach the lid, turn upside down and place on a flat surface and retreat. Lid pops off, Water goes down, tube goes up. Momentum conserved. Neighbours impressed.

2/ Roundabout, as a demonstration of the conservation of angular momentum. Get on. Start turning. Move to the middle, move to the outside. See when the roundabout turns faster.

3/ Roundabout, as a demonstration of the centrifugal force. Start turning, place ball on floor, watch ball.

4/ Roundabout, as a demonstration of the Coriolis force. Both get on. Start turning, throw ball to other person. Stop turning. Turn other way. Throw ball. Throw up.

I sadly forgot to take a pendulum on the roundabout to demonstrate the principle of the Foucault pendulum. Next week. I like roundabouts. Why are they only given to children? Why don't physics institutes have roundabouts in the Foyer?

I think I could get to like physics again, as long as I don't have to spend too much time with physicists, and as long as it isn't a job requirement.