A simple 'Resonance Apparatus'. Consists of a 1m long vertical stand with metric scale and a 20mm plastic tube connected to a 1L vessel of water. The vessel of water is placed so that the level of water in the tube is adjustable by raising and lowering the vessel. A tuning fork is provided to check for resonance by listening at the mouth of the tube as the level is adjusted. The various lengths of the air column where resonance is evident are marked and calculations are made to determine the wavelength and frequency of the tuning fork.