Use of em waves

• What should you be able to describe by the end of the video?

  Uses of electromagnetic waves
• What is required from higher tiered students regarding electromagnetic waves?


  Explain why each wave type is suitable
• What are some uses of radio waves?

  • Transmit radio signals
  • Transmit terrestrial TV signals
• Why are radio waves suitable for transmitting signals?

  They can travel long distances before absorption
• What is terrestrial TV?

  TV received using an aerial
• What phenomenon allows longer wavelength radio waves to spread between hills?

  Diffraction
• What is the ionosphere?

  A layer of charged particles in the atmosphere
• How do radio waves travel long distances around the Earth?

  They reflect off the ionosphere
• What are the uses of microwaves?

  • Heating food
  • Communicating with satellites
• Why are microwaves effective for heating food?

  Water molecules absorb microwave energy
• Why can microwaves communicate with satellites?

  They pass through the Earth's atmosphere
• What are the uses of infrared waves?

  • Emitted by electrical heaters
  • Used in cooking food
  • Used in infrared cameras
• How does infrared energy affect room temperature?

  It is absorbed by objects, warming them
• What is a key use of visible light?

  Communication using fiber optics
• What are optical fibers used for?

  Carrying telephone and cable TV signals
• Why can visible light carry a great deal of information?

  It has a short wavelength
• What are the uses of ultraviolet light?

  • Energy-efficient lightbulbs
  • Sun tanning in tanning beds
• Why are energy-efficient lightbulbs advantageous?

  They require less energy than normal bulbs
• What is a risk associated with ultraviolet light?

  Increases risk of skin cancer
• What are the uses of x-rays and gamma rays?

  • Medical imaging
  • Treating cancer
• How do x-rays visualize broken bones?

  They are absorbed by bones
• What is a key use of gamma rays?

  Detecting cancers
• How do x-rays and gamma rays differ in their medical applications?

  X-rays visualize bones, gamma rays detect cancers
• Why are x-rays and gamma rays considered penetrative?

  They can pass easily through body tissue
• What can both x-rays and gamma rays be used for in medicine?

  Treating cancer
• Where can students find questions on electromagnetic spectrum uses?

  • In the vision workbook
  • Available via a link in the video