PURPOSE: To observe the change in wavelength of a vibrating rope as the tension is varied.

DESCRIPTION: Set the generator frequency using about 250g to produce 2 loops. Quadrupling the weight increases the wave speed (and thus the wavelength) by about a factor of two, creating one loop, while using about 110 grams creates three loops, two-thirds of the original wavelength. This is Mersenne's second law for stretched strings.

SUGGESTIONS: See Question of the Week #262 and #263 for information on using this demonstration to enhance class involvement.

REFERENCES: (PIRA 3B22.15)

EQUIPMENT: Mounted rope wave generator with weights.

SETUP TIME: None.