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RADIO WAVES
 What are radio waves?
Radio waves are part of the electromagnetic spectrum. They carry information and travel at the speed of light - 300,000 km per second. They can travel through a vacuum, the air and some solids, but not metal.
The radio wave part of the electromagnetic spectrum is divided up into into areas or bands each of which have different wavelengths and frequencies. Wavelength is the distance between two peaks on the wave - and frequency - the number of waves every second. Frequency is measured in cycles per second or hertz - Hz. |
Radio waves have the longest wavelength of any waves in the electromagnetic spectrum. Long Waves have up to 3 km between successive peaks (about the distance across a small town). However, they travel so fast that 100,000 waves reach a radio every second. This means that 3 km radio waves have a frequency of 100 kHz.
An AM radio station with a frequency of 750kHz - about the middle of the AM dial - uses a wavelength of about 400 metres. An FM station has a higher frequency of 100MHz (1 MHz = 1000kHz) but has a shorter wavelength - about 3 metres.
What are radio waves used for? |
Microwaves: |
Mobile phones, Satellite TV & communications, Microwaves (one specific frequency used for cooking) |
UHF: |
TV broadcasts, Digital TV broadcasts |
VHF: |
FM radio broadcasts, Radio controlled models |
Short wave: |
Police radio, Aircraft radio |
Medium wave: |
AM radio broadcasts |
Long wave: |
AM radio broadcasts Ship to shore radio |
How are radio waves generated?
Radio waves are generated by accelerating electrons inside an antenna (or aerial). Antennas are usually carefully designed but something as simple as a length of wire or a wire coil can also act as an antenna. A sensitive radio receiver would be able to detect the radio waves from these simple antennas.
Radio waves and Robot Constructor
If the robot you've designed in Robot Constructor relies on rechargeable batteries for its power supply, you'd benefit from giving the robot a radio receiver as one of its sensors. This is because the robot would then be able to detect the battery chargers located around the zones more easily - battery chargers contain components like coils of wire which radiate low level radio waves.
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SENSORS radio infra red light radiation
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