Longitudinal waves in a spring in slow motion (0:47)
Transverse waves in a spring in slow motion (0:28)
String instruments are an example of transverse wave.
Guitar Strings – Slow Motion World (1:59)
You can tell the frequency of a stringed instrument by looking at the waves in the strings.
Guitar strings vibrating (0:28)
Violins work using a similar principal.
Bowed violin string in slow motion (2:59)
Slinky tricks (0:32)