Earth's atmosphere] [information over pictures] [1]

The atmosphere is a protective layer of gases which surrounds the Earth.	If the Earth were the size of an apple the atmosphere would only be as thick as the apple skin.	This is an actual view of the atmosphere as seen from space. It is this tiny layer which we are damaging with our pollution.
The atmosphere is made up of 78% Nitrogen 21% oxygen [the bit we breathe] and 1% of other gases.	It also protects us from the harmful rays of the Sun's radiation.	At the same time it traps some heat in keeping the Earth warm much like a greenhouse does.

Look at all of the pictures in turn. As you hover over each one a blue screen appears with an explanation of what the picture shows. Important words are underlined. If you are certain that you know about the picture click on it and it will disappear. As you go through all of the pictures you will get rid of all those which you know about and be only left with those you may be unsure of. In some cases you may get rid of all of the pictures in which case you are ready to move on to other activities which will test your knowledge on that particular topic.