Mass Spectrometer Model
To demonstrate approximately how a mass spectrometer works for an outreach project at the Museum of Science and Industry in Manchester I built a ball bearing deflector. It works by having a ramp, that you roll ball bearings down, and at the bottom they go past a magnet. The small ball bearings are deflected more than the large ones, a bit like the ions in a real mass spectrometer. Apparently it went down well.