(i) State which physical property of an acoustic wave must be increased to make the sound louder.

(ii) State which physical property of an acoustic wave must be increased to make the pitch of the sound higher.

Seismic P-waves travel through the Earth's crust as longitudinal waves.

(i) Seismic S-waves are transverse waves. State one other example of a transverse wave, excluding seismic waves and visible light.

(ii) Describe how the oscillations of particles in longitudinal waves and transverse waves differ relative to the direction of energy propagation.