There are 4 layers of the earth's atmosphere, the troposphere, stratosphere, mesosphere, and thermosphere. Each layer has a certain job.
Troposphere is the layer that we live in. It is colder in this layer and weather occurs here. Next is the stratosphere, this layer gets warmer as you go higher and the ozone layer is found in the stratosphere. The ozone layer protects us from the sun. The 3rd layer is the mesosphere. The mesosphere is colder and it protects us from meteors. Lastly is the thermosphere, it is pretty warm in this layer because the sun strikes it first. The Auroras/Northern Lights happen here.
Temperature alternates as you go higher. Each layer has a different temp. It starts out cold then goes warm, cold, hot.
Pressure decreases as you get higher in the atmosphere, and it increases as you go lower in the atmosphere. For example, when you are in an airplane and your ears pop its because the pressure is a lot lower up high.
Nitrogen makes up 78% of our earth's atmosphere, Oxygen makes up 28%, and all of the other gases make up 1% of our atmosphere.
The greenhouse effect is when the suns radiation is absorbed by the land and water and turned into infrared radiation, where some energy goes back out into space and some stays trapped here in earth.
Pressure is always pushing and moving in different directions. Pressure is constantly pushing because of the weight of the atmosphere. Like in our experiment when we tried to blow the balloon up in the bottle, it was hard because the pressure from the balloon was pushing down and the pressure from inside the bottle was pushing up.
Our atmosphere is important to us in many, MANY ways! Here are a few, the mesosphere protects us from meteors, the stratosphere protects us from the sun, and it keeps us warm. Without it we would be crushed by meteors, burned to death by the sun, or frozen to death.