How things work college course/Breaking broomstick demonstration

This is not really a lab but a demonstration. I am looking for ways to make it more educational. These are ideas I have jotted down.

Waves that travel at the same speed for all wavelengths

  • Light in vacuum
  • Sound
  • Transverse and longitudinal waves on a string
  • Shallow water waves (approximately)

Waves that travel at a speed that depends on wavelength