Communicating using waves

Question 1

What type of waves are used for communication?

Answer 1

Electromagnetic waves, because they travel very fast

Question 2

What type of electromagnetic waves do mobile phones send and receive?

Answer 2

microwaves: when you talk to your phone, your phone converts sound into a microwave signal which it sends to the nearest phone mast

Question 3

How do microwaves travel?

Answer 3

They can travel over large distances, but need a line of sight between the phone and receiver.
They travel in straight lines, so in places with hills sometimes the signal cannot get through.

Question 4

What can affect microwaves?

Answer 4

• Hilly areas (travel in straight lines so need a line of sight)
• Poor weather conditions
• Large surfaces of water
• Very long distances (curvature of Earth means there is no line of sight)

Question 5

What causes signal loss when communicating with microwaves?

Answer 5

• Weather conditions like heavy rain and large surfaces of water scatter the signal, making it more difficult to receive.
• Radio waves spread out or diffract whenever they pass through a gap, but when microwaves travel through the air they don’t spread out as much. This makes line of sight even more important.
• Other types of electromagnetic waves can interfere with the microwave transmission. To reduce both of these effects, microwave transmitters are usually placed close together to ensure the signal remains strong. They are also placed high on hills to avoid obstructions.

Question 6

Will mobiles fry your brain?

Answer 6

• some research shows it has a small heating effect on the brain
• no clear evidence
• uncertain on long term damage (new technology)
• NHS recommends no regular use at young age
• have to make own decision