Pop crash ring
Today I had a 2 hour lesson with one of my first year classes. It's a special arrangement for the end of term so that we can run trips and do things that would normally not be possible. 2 hours is still not quite enough for a design experiment but much better than 1 hour. The topic for today's lab was balloons. I bought some pumps to add an extra twist but they weren't much good so not many students used them. The students pictured are investigating the resonance frequency of the balloon by making it vibrate with a vibration generator. Several groups investigated the air being blown out from the balloon and discovered that the maximum force is not when the balloon is biggest, interesting. One group used the electrometer that I fixed the other week to measure the potential near a charged balloon. This has to be done at quite a distance since the electrometer only measures up to 300V.
If there is one thing that I would change about my lab it is the way I store rulers. I have a set of 1m long metal rulers that I keep on the chalk tray under my now redundant chalk board. It's the green thing in the photo if you've never seen a chalk board. At least once every lesson a ruler falls onto the floor and it makes the most horrible noise. I've recorded it here.
Horrible but at the same time interesting. Crash then ring. OK more horrible than interesting.