Unit 1.5

• Types of waves

  • Longitudinal
  • Transverse
• Transverse wave

  • Vibrations at 90º to the direction of travel
• Longitudinal wave

  • Vibrations parallel to the direction of travel
• Refraction causes a change in direction and wavelength due to a change in speed
• Reflection does not change the wavelength, and the angle from the normal to the wave when it hits the object is the same as when it is reflected
• Types of satellites

  • Geosynchronous
  • Geostationary
• Geosynchronous satellite

  Returns to the same point once every 24 hours
• Geostationary satellite


  Stays above the same point at all times
• Using geostationary satellites to send messages


  1. Signal travels up to the satellite and back

  2. Cannot travel straight from one satellite to another without returning to a station on the ground first

  3. Requires at least 3 satellites
• Wave speed

  • Distance (m) / Time (s)
  • Wavelength (m) x Frequency (Hz)
• There are two complete waves shown in the example
• Wave

  • Wavelength = length of one complete wave
  • Amplitude = maximum displacement
  • Frequency = number of waves in 1 second
• Parts of the electromagnetic spectrum

  • Radio waves
  • Microwaves
  • Infrared
  • Visible light
  • Ultraviolet
  • X rays
  • Gamma rays
• Electromagnetic spectrum

  • All parts transfer energy
  • All are transverse waves
  • All travel at the same speed in a vacuum (3 x 10^8 m/s)
  • Have different properties and uses
• Higher optical density/shallow water results in slower speed and shorter wavelength
• Lower optical density/deep water results in higher speed and longer wavelength