Physics

• Measure the Speed of Sound

  1. Build two speakers to generate sounds with a specific frequency

  2. Use an oscilloscope to detect the strength of the sound waves generated

  3. Place the speakers so the detected waves are in phase

  4. Slowly move one speaker away until the two waves are out of phase

  5. Measure the distance between the two speakers when the waves are out of phase to find one wavelength (λ)

  6. Use the formula (v = fλ) to find the speed (v) of the sound waves
• Measure the Speed of Water Ripples Using a Lamp

  1. Set up a ripple tank with a lamp

  2. Observe the shadows of the ripples on a screen below the tank

  3. Measure the distance between shadow lines that are 10 wavelengths apart, then divide this distance by 10 to find the average wavelength

  4. Use the wave equation (v = fλ) to calculate the speed of the waves
• Measure the Speed of Waves on Strings

  1. Set up the equipment with a signal generator and vibration transducer

  2. Adjust the frequency of the signal generator until there is a standing wave on the string

  3. Measure the length of several half-wavelengths and take the mean to get the full wavelength

  4. The frequency of the wave is whatever the signal generator is set to

  5. Use the wave equation (v = fλ) to find the speed of the wave
• Sound waves, ripples, and waves on strings are used as model waves because they're easy to work with
• Reflection


  When a wave hits a boundary between two different materials, it can be absorbed, transmitted, or reflected
• Reflection


  • Angle of incidence = Angle of reflection
• Specular reflection


  Waves are reflected in a single direction by a smooth surface
• Diffuse reflection


  Waves are reflected by a rough surface and the reflected rays are scattered in lots of different directions
• The angle of incidence is always equal to the angle of reflection of a wave
• Type of reflection


  • Specular reflection
  • Diffuse reflection