Waves for detection and exploration: Waves: Physics: GCSE (9:1)

• Ultrasound


  Sound waves that have a frequency higher than the upper limit for human hearing (above 20,000 Hz)

  
• Uses of ultrasound

  breaking kidney stones, cleaning jewellery, ultrasound scans, echo sounding

  
• Using ultrasound for breaking kidney stones and cleaning jewellery

  The vibrations caused by the ultrasound waves shake apart the dirt or kidney stones and break them up
• Using ultrasound waves for imaging

  The waves are partially reflected when they meet a boundary between two materials and the time taken for the reflected waves to reach a detector can be used to determine how far away the boundary is

  
• Seismic waves


  Waves produced by earthquakes

  
• P-waves

  Longitudinal, seismic waves

  
• S-waves


  Transverse, seismic waves that cannot travel through a liquid

  
• How P-waves travel

  P-waves are faster than S-waves and can travel through solids and liquids

  
• How S-waves travel

  S-waves are slower than P -waves and can only travel through a solid

  
• Uses of seismic waves

  P-waves and S-waves provide evidence for the structure and size of the Earth’s core

  
• Echo sounding


  When high frequency sound waves are used to detect objects in deep water and measure water depth.

  
• Echolocation


  A similar method to echo sounding that animals such as bats and dolphins use to detect their surroundings and to find food