How do you find the wavelength of a longitudinal wave? - Answers

If you sit on it, you will feel it bunch up and spread out underneath you. Time how long it takes between bunchings. This time is called the period. You may need to remove your trousers for a more sensitive measurement.You also need to measure how fast the wave is travelling. Sit sideways on it, and time how long it takes between a bunching under one buttock and then under the other. This time is the interbuttock consecutive excitation interval. Take the reciprocal, and multiply by your interbuttock separation distance (which you can get from your doctor). The result is the wavespeed.Now, all you need to do is multiply the period by the wavespeed, and the answer will be the wavelength.