Ideas for making a Physics Demonstration?

[csnsc14320]

For my lab class we have to make some sort of physics demonstration in our machine shop with a budget of ~$600-$1000. I was wondering if anyone on here had some suggestions as to some cool/fun things to make?

Things along the lines of Van De Graaf generators, inverted pendulums, etc. can be made (anything that isn't too easy and can be used to demonstrate some topic of physics)

Also, we were taught to use LabVIEW last quarter so if that opens up any other possibilities, I'm interested in hearing some ideas!

 

[Andy Resnick]

We have an excellent demo of Eddy currents: 2 cow magnets (one with the pieces opposing to have a near-zero net field) and a close-fitting tube of aluminum. One magnet falls through normally, the other takes about 10x as long.

 

[PhaseShifter]

An idea I just had today--I want to attempt building a cheap spectrometer from a Pringles can (using an old CD-ROM as a diffraction grating).