Gasses Of the Atmosphere
Nitrogen makes up 78%, oxygen makes up 21% and other gasses make up 1%.
The trosphere gets colder as you go up.
Weather only occurs in this layer.
90% of the mass is found here.
The Greenhouse Effect
The greenhouse effect keeps the Earth's atmoshere warm.
The sun puts heat into the Earth and some heat escapes into space, while the rest stays in the atmosphere.
When you go up into the atmosphere the pressure gets lower. Because when you go up the air gets spread out.
As you go up in the atmosphere the tempature gets colder then warmer, then colder, then very hot.
The Atmospher's Importance
The atmosphere is important because it keeps the tempature just right. Also it traps the air in.
How Big the Atmosphere is
The atmosphere would be as thin as an apple if the Earth was an apple.
If you went down to the core of the Earth you would get squashed. It's because there is so much air above you its pushing you down and crushing you.
If you went up into the atmosphere would would blow up like a balloon. It's because there is less air pushing down so your body expands.