6.2 Light, infared, microwaves and radio waves
Visible light is the part of the electromagnetic spectrum that is detected by our eyes. We see different wavelengths within it as different colours.
The wavelength increases across the spectrum from violet to red. a mixture of all the colours is seen as white light. Visible light can be used for photography.
Infrared radiation is given out by all objects. The hotter the object, the more IR it emits. Remote controls for devices such as TV's use infrared.
Microwaves are used in communications. Microwave transmitters produce wavelengths that are able to pass through the atmosphere. They are used to send signals to and from satellites and within mobile phone networks.
Radio waves transmit radio and TV programs and carry mobile phone signals.
Microwave radiation and radio waves penetrate your skin and are absorbed by body tissue. This can heat internal organs and may damage them.
Infrared radiation is absorbed by skin; too much will burn your skin.