The Classic Slinky
Objective: To show and compare different types of waves traveling through a medium, a slinky medium.
Each firmly holding one end you and a student volunteer stretch out the slinky in the front of the class (do not stretch it too far, as this will permanently bend the coils). Tightly holding the slinky with your whole hand, hit your hand firmly to send a wave through the slinky. Hitting the back of your hand will send a P-wave through the slinky, hitting the side of your hand will send an S-wave through the slinky, and hitting your hand at an oblique angle will send both P and S waves through the slinky at once (this can be somewhat tricky). Have the students make observations about the shape and speed of the different waves. The video camera can be used to project the demonstration on the screen.
Illustrated below is the magical slinky.