ripple tank

• RP08 - Waves (Water Waves in a Ripple Tank)

  1. Fill the ripple tank so the water has a depth of approximately 5mm.

  2. Place a wooden rod on the surface of the water and attach it to the low-voltage power supply and motor. Add a lamp to the circuit and hold the lamp above the ripple tank.

  3. View the wave pattern from the side of the tank, looking through the water.

  
  

  
  

  4. To measure the wavelength, place the metre ruler perpendicular to the wavefronts on the page. Measure across as many wavefronts as possible and divide by the number of waves.

  
  

  5. To measure the frequency, count the number of waves passing a particular point in the wave tank over a given time (measure 10 or 20 seconds using a stop clock).

  
  

  6. To calculate the wave speed, multiply the wavelength by the frequency.
• RP08 - Waves ( Standing Wave on a Vibrating String)

  1. Produce a standing wave on the vibrating string by adjusting the frequency or the generator, the position of the wooden bridge and the tension in the string (by adding or removing masses). A standing wave is created when the wave doesn't appear to move horizontally, instead the string appears to oscillate only vertically.

  2. To measure the wavelength, use a metre ruler to measure across multiple standing waves and divide by the number of total waves.

  The wavelengths of a standing wave is measured across two halves, as shown in the diagram to the left.

  3. To measure the frequency, use a stopwatch to time wave oscillations over ten complete cycles. If the wave is slow enough, time the point at the centre of the half-wavelength, starting at equilibrium and counting every other time the string passes the equilibrium as a complete cycle. Divide this value by 10 to find the time period. Then use the equation

  frequency = 1/time period