required practical 8

• Ripple tank


  A shallow tray of water with a vibrating bar that creates waves across the surface of the water
• Ripple tank


  • Has a lump below the tank and a sheet of white paper, when light shines through the water it produces an image of the waves on the paper
• Measuring wavelength


  Place a ruler on the paper, freeze the image of the waves, measure the distance between one wave and 10 waves, divide by 10 to find one wavelength
• Measuring frequency


  Place a timer next to the paper, count the number of waves passing a point in 10 seconds, divide by 10 to find the frequency in Hertz
• Measuring wave speed


  1. Use the wave equation: wave speed = frequency in Hertz x wavelength in meters

  2. Select a wave and measure the time it takes to move the length of the tank, divide the distance traveled by the time taken
• Measuring wave speed using the two methods may give slightly different results due to measurement errors
• This is a required practical, you'll find plenty more questions on it in the revision workbook