Objective Materials To observe the properties of resonance tubes. ? Variable length resonance tube ? W a t e r ? 1024 Hz tuning fork ? 2048 Hz tuning fork ? Rubber mallet Procedure:You will send a sound wave down a tube almost full with water. You vary the length of the air column (above the water level) in the tube by changing the level of water in the tube until you do a standing wave that amplifies the sound. Each frequency will make an antinode at the tube opening and a node at the water surface for four lengths. Each length corresponds to a different harmonic. 1. Before starting the experiment, you should compute the theoretical values of the tube lengths where you are creating standing waves. Using an estimated speed of sound of 345 m/s, compute the expected tube lengths using the following equation for two different frequencies, 1024 Hz and 2048 Hz: fn = n (v/4L) = 1, 3, 5, ... When n = 1 f1 = (v/4L); L = v/(4f1) f=1024 Hz, v=345 m/s; L = 345/(4 * 1024) = 0.084 m = 8.4 cm f=2048 Hz, v=345 m/s; L = 345/(4 * 2048) = 0.042 m = 4.2cm