Why does air pressure decrease as you go up in altitude?

Question

Please explain it in a way I will easily understand, im am only 14.

Answer 1

Gravity holds the atmosphere near the Earth, and the nearer something is to the Earth, the stronger the pull of gravity. For the air, the result is a kind of "packing" that makes for higher density and increased pressure. At higher altitude, the packing is not as good, and the pressure is lower.

Answer 2

air is made up of molecules (which are atoms bonded together somehow). Eg, oxygen in the air is really two atoms of oxygen bonded together, Carbon dioxide is carbon bonded with two oxygen atoms.

I should said air pressure is essentially the force of air on any given area. Have you ever watched those submarine movies where the submarine losses power and it starts sinking towards to bottom of the sea? Notice that they always say the submarine will be crushed and you always sea pipes bursting. It's the same principle! The deeper you go, the more compressed the water becomes because the weight of the water above it compresses it. Take a lemonade bottle and put a hole right at the bottom, one in the middle and one near the top. Fill it up with water and see what happens. The water coming out of the bottom hole goes further than water from the other holes. The pressure of water at the bottom is bigger than that at the top.

So think of air as water, and the same principle applies. The air at sea level is being compressed by all the air above it. As you go higher there is less and less air (air sinks since it has weight) and so the pressure it is under is less.

When aeroplanes fly they usually decrease the air pressure in the cabin (why you ears pop). The reason they do this is because of dangers of high air pressure. At high altitudes the outside air pressure is low. Essentially the the force of the air pushing on the cabin goes down as you go up. Now the inside of the cabin has it's own air pressure (since it's sealed). If the cabin's air pressure was too much higher than the outside then the cabin would explode out. So what they do is lower the cabin pressure so the outside and inside air pressures are more similar.

Another experiment, take a lemonade bottle (with no holes in it) and suck the air out of it. What happens? The bottle 'scrunches' up. Why? Because by sucking the air out, you decreased the air pressure inside the bottle. The outside air pressure is bigger than the inside air pressure and so the outside air pressure pushes on the plastic of the lemondade bottle thereby compressing it (exactly the same situations as the submarine).

Hope that helps

Answer 3

Because there is less gravity at higher altitudes. Air has weight and is more condensed near the surface of the earth where gravity is stronger.

Answer 4

Air pressure is caused by the weight of all the air above you. So as you go higher, there's less air above you pressing down.

Answer 5

The air outside is thinner, internal air pressure tries to compensate.

Answer 6

Air has weight and it is felt as pressure, the deeper we are in a sea of air the more air is pushing on us.

Answer 7

Because there is less air on top of it (the air) pressing down on it (due to gravity). Yes gravity even effects things as small as an atom.
And atoms make up molecules, like I am sure you have heard of H2O, or water. Well H2O is water's scientific name, because for every 2 hydrogen atoms (H2) there is one oxygen atom (O)to make H2O. (water) Give yourself more credit, I mean it is not like you are an [e-mail]

Answer 8

as you go up there is less air to push on you. For example, if you were under a pile of bricks and working your way up and out...you would have less pressure as you go up. Also air is part of the atmospere and gets thinner as you go up.

Answer 9

even gases have weight
some weigh more than others
as you go up in altitude there is less heavier gas than on ground

Answer 10

Becaue there is less air, simple answer.