1. Electromagnetic waves
5.4 Microwaves and radio waves

2. Learning outcomes
Be able to describe the properties of microwaves and radio waves
Understand the uses and dangers of these waves

3. EM Radiation: Uses: Dangers:
Microwaves
Satellite communication, mobile phone networks, cooking, RADAR.
Internal tissue heating.

4. How do microwaves cook food?
Microwaves can be used in c_____ because many foods contain w____ molecules. Microwaves of the right w________ are able to make the water molecules r_______. This causes the food to get h____.
ooking
ater
avelength
esonate
otter

5. EM Radiation: Uses: Dangers:
Radio waves
EM Radiation: Uses: Dangers:
Radio waves
Communication and astronomy.

6. Radio waves How do radio signals from the UK reach around the globe?
The longer wavelength radio waves from a transmitter reflect off the Earth’s outer atmosphere (ionosphere).

7. Radio waves
How can houses in the shadows of hills receive a radio signal?
All electromagnetic radiation travels in straight lines, does it not?
Radio waves diffract around the hill to the house.
Remember diffraction?