1. The problem statement, all variables and given/known data A glass tube is closed at one end. The air column it contains has a length that can be varied between 0.50m and 1.50 m. If a tuning fork of frequency 306 Hz is sounded at the top of the tube, at which lengths of the air column would resonance occur? (Take the speed of sound to be 330 ms-1.) 2. Relevant equations When we want to check where resonance occurs, how do we know whether the standing wave created is first, second or third harmonic?