2. What is radiation?
We know that conduction mainly takes place in solids, and convection takes place in liquids and gases. How does the Earth receive heat energy from the sun through the empty vacuum of space?
There is a third kind of heat transfer, which is called radiation, or ‘infra-red radiation’.

3. Absorbing radiation Teacher Notes
Here are some discussion points in the cartoon:
The Sun – is the source of a great deal of radiated heat energy.
The cricketers – by wearing white, the cricketers stay cool and can run around without getting too hot.
The goths – wearing black has made them hot, sweaty and miserable. One of them has had enough and ripped off his clothes! Will he be hotter or cooler without them?
The white geese – are happily swimming around, as they are not too hot.
The brown ducks – have got too hot and are hiding in the shade.
The woman with the push chair – is using light-coloured items to protect herself and the child from the sun. Note the difference between her two dogs.

4. Seeing infrared radiation
The police and fire service use infra-red cameras to find people in the dark.
Infra-red has no colour, but a computer can put a false colour on the camera image so we can ‘see’ the object.
The colours are put on a scale which corresponds to temperature. White, yellow and red usually represent the warmest areas; green, blue and black usually represent the coolest.