Longitudinal and transverse waves.

Interference of waves on the surface of water.

Reflection of single circular waves and passing them through a semitransparent wall. Shock waves. Huygens'  principle.

Two modes of oscillation in crystals. Phonons.

Generation of acoustic waves by loudspeaker.

The Doppler effect in acoustics. The frequency of the detected signal is changed if the source and receiver move relatively to each other.

Fourier Series. Signal harmonics.

Generation of shock waves by a moving body. The Doppler effect.