A slinky provides a useful visual tool for demonstrating longitudinal wave pulses. Using a high speed camera (Casio EX-FH20) allows us to discover some interesting things about longitudinal wave propagation on the slinky. First, the propagation speed of longitudinal waves depends on the number of coils the slinky has. For two slinkys stretched to the same distance, waves travel slower on the slinky with a larger number of coils. Secondly, the propagating time for a pulse to travel from one end of a slinky to the other is independent of how far the slinky is stretched. Stretching a slinky increases the elastic modulus and decreases the mass density so that the wave speed is linearly proportional to the stretched length. Waves travel faster on a slinky that is stretched farther, but they will travel that farther distance in the the same constant amount of time, which depends on the number of coils. Music soundtrack is an arrangement of the 1969 Perrery & Kinsley "Pop Corn" (originally written for and performed on the Moog Synthesizer). This disco pop version is by the group Hot Butter from their album "Hot Butter & Jam"

Be the first to comment