5.3.4 microwaves and radio waves

• Uses of microwaves

  • satellite communications
  • transmitting signals from phone mast to mobile phone
  • cooking food - microwaves are absorbed by water, heating up the water in the process, food contains a lot of water
• Risks of microwaves

  • exposure to microwaves could be harmful because microwaves are absorbed by water, and humans are made up of a lot of water
• Exposure to microwaves should be reduced. As with X-rays, always have some sort of shielding between the source of microwaves and living tissue. e.g. shielding on microwave ovens
• Microwaves have enough frequency to penetrate the Earth's atmosphere, allowing it to reach satellites. They travel in straight lines through the atmosphere, making them good for transmitting signals
• Radiowaves can be transmitted around the Earth's surface and around buildings without interference due to the long wavelengths
• Uses of radiowaves

  • TV communications
  • radio communications
• Risks of radiowaves

  • at high intensities, radiowaves can cause internal heating of living tissue with potentially harmful effects