Introduction to Waves (Edexcel GCSE Physics: Combined Science)

• Waves transfer energy and information
• Waves are described as oscillations or vibrations about a fixed point
  • For example, ripples cause particles of water to oscillate up and down
  • Sound waves cause particles of air to vibrate back and forth

• In all cases, waves transfer energy without transferring matter

• Objects floating on water provide evidence that waves only transfer energy and not matter

Step 1: Identify the type of wave

• • The type of wave on the surface of a body of water is a transverse wave
  • This is because the duck is moving perpendicular to the direction of the wave

Step 2: Describe the motion of the toy duck

• • The plastic duck moves up and down but does not travel with the wave

Step 3: Explain how this motion demonstrates that waves do not transfer matter

• • Both transverse and longitudinal waves transfer energy, but not the particles of the medium
  • This means when a wave travels between two points, no matter actually travels with it, the points on the wave just vibrate back and forth about fixed positions
  • Objects floating on the water simply bob up and down when waves pass under them, demonstrating that there is no movement of matter in the direction of the wave, only energy