If you were going upward in a hot air balloon would the atmospheric pressure increase or decrease explain?

Question

does it decrease because the number of molecules of air around you decrease?

Answer 1

Pressure will decrease.  Think of it this way, the pressure at a certain atmospheric level is basically the the force exerted by everything above.  A big part of this force comes from the weight of all the molecules above it.  

So let us say we have a long tube filled with water that you must carry across a roof top.  The top of this tube must reach the height of an adjacent 100 story building.  If you were given a choice to carry a tube of water from either the street level with a 100 story tube of water or you can go to another adjacent 80 story roof top and carry a 20 story long tube of water, which one would you thin would be easier to lift and carry to another location?  The pressure contributed from the total volume of water from the 100 story long  tube of water at ground level would be more difficult to carry...right?

And that would the same kind of reasoning of why the pressure at a higher altitudes would most likely be lighter. You are dealing with a smaller amount of air molecules above you exerting a downward pressure (mainly due to gravity) at that given height level.

Answer 2

Decrease for several reasons. I'll give you the two main ones. Parcels of air tend to spread out the farther up you go with a larger atmosphere to cover. Think of a balloon it's thicker when its deflated and smaller and thinner when inflated and bigger. Also, and this is probably the biggest reason, on the ground, you have all of the atmosphere coming down on your head, and the higher up you go the less atmosphere is weighing you down. It like the ocean the deeper you go, the more pressure you have. We're at the bottom of the air ocean.

Answer 3

The atmospheric pressure is nothing but the weight of the overlying column of air over a place.As you go up,the length of this air column decreases with a corresponding decrease in weight and hence the pressure also decreases with height.

Answer 4

As you traveled upwards in your hot air balloon the atmospheric pressure would decrease.  Atmospheric pressure is how much air is above you.  Air has weight, and the more air on top of you, the heavier it is.  As you rise in your balloon, there is less air above you and more below you, so the pressure on you becomes less.

Answer 5

decrease...   there is less atmosphere(thinner)  therefore lighter... so less pressure