P2 - EM Spectrum.

Radiation is just a tranfer of energy.

For Example: Sunlight is a transfer of energy from the Sun to the Earth.

Visible light, which is the colours of the rainbow (from red to violet), is just radiation that our eyes can detect. Radiation further along in the red direction is called infrared and radiation further along in the violet direction is called ultraviolet.

There are seven types of radiation and together these make upthe EM spectrum:

• Radiowaves                                        Rich
• Microwaves                                         Men
• Infrared                                               In
• Visible light                                         Vegas
• Ultraviolet                                            Use
• X-ray                                                   Xpensive
• Gamma rays                                       Girls

All types of electomagnetic radiation transfer energy.

For Example: You can feel the warmth of the Sun because the heat energy is travelling through space as infrared radiation.

This energy is delivered as photons. A photon is a tiny 'droplet' or 'packet' of energy.

Imagine droplets of water from a very 'fine' shower - but made of energy rather than water.

Sometimes it's more useful to think of light as a wave.

For Example: It would be easier when talking about reflection and things like that.

When you think of the energy transferred by electromagnetic radiation it's sometimes easier to think about photons.

Each photon carries a tiny quantity of energy, but not all photons have the same amount of energy. The amount of energy carried by a photon depends on the frequency of the radiation.

The frequency, and so photon energy, increases as you go along the EM spectrum.

Radio wave photons have the lowest frequency and the least energy.

Gamma ray photons have the highest frequency and the most energy.