Waves on a String

What You’ll Do

  • Measure the speed of waves on a string
  • Find out how changing the tension on the string changes the wave speed
  • Produce high-harmonic standing waves on a string

Resources

  • stand, clamps, and pulley
  • mechanical wave driver
  • frequency generator
  • mass holder (50 gram) and masses
  • string
  • meter stick

Background

The speed at which the shape of a wave appears to move through the medium is equal to its wavelength times its frequency. The speed of waves is fixed by the properties of the medium, and is not change by producing waves of different frequency or wavelength. For example, a wave on a stretched string has a speed where T is the tension in the string and μ is the mass per unit length of the string.

When waves can be reflected in a system, standing waves can be produced. Standing waves will only be produced for wavelengths that reflect back upon themselves in a symmetrical way. For waves on a string between two fixed points L, the wavelengths produced are where n is the harmonic number of the wave.

Waves on a String Worksheet