2006-11-13 00:33:29 · 10 answers · asked by raine01_21 1 in Science & Mathematics ➔ Physics
W = mg; where W = weight of the air, m = mass of the air, and g = 9.81 m/sec^2 acceleration due to gravity at Earth's surface.
m = rho V; where rho = air density and V = the volume of air. V = A h; where A = cross sectional area of a column of air h high.
rho = m/V = W/(Vg) = W/(A h g) = P/(h g); where P = W/A = atmospheric pressure
Thus we see that, at a given atmospheric pressure (P) the density of the atmosphere (rho) decreases as h (the height of a column of air) gets bigger.
In ordinary words, the density of air decreases with height because there is less and less air piled on top of the atmosphere with increasing height. Thus, there is less air to push the air molecules close together at higher heights...and density is a measure of closeness.
2006-11-13 03:53:27 · answer #1 · answered by oldprof 7 · 3⤊ 0⤋
Density Of The Atmosphere
2016-11-12 21:52:59 · answer #2 · answered by jodie 4 · 0⤊ 0⤋
2 reasons, both have been mentioned above.
1. The main reason is air pressure. At the bottom of the ocean the pressure is very high because of all the water piled up above. Same thing with air, the pressure increases closer to the ground because of all the air piling on above. This pressure near the ground forces the air molecules closer together making the density higher. Water in the ocean doesn't compress under pressure, but air does.
2. The other thing is that the gravitational pull is higher close to the ground.
2006-11-13 01:49:38 · answer #3 · answered by sojsail 7 · 1⤊ 0⤋
Gravity ! The weight of the air is thicker / denser closer to the attractive force of gravity, the Earth.
Air does have weight. This can be proven by weighing an inflatable ball before and after it has air.
Another example of lesser effects of gravity at higher altitudes were the high jump records set in the Olympic games in Mexico City 1960. Most records are slightly beaten and last only 4 years. The records set in Mexico which is at a very high altitude, stood for decades. endurance athletes, however (Marathon) had a very hard time there with lesser Oxygen.
2006-11-13 00:42:26 · answer #4 · answered by wizebloke 7 · 0⤊ 0⤋
The acceleration due to gravity at the top of the atmosphere is almost identical to that at the bottom (its less than 2% different).
Air pressures is due to the weight of the column of air above you. This is highest at sea level. As you rise there is less air above you - so less weight, and less pressure.
Gases are compressible so as the pressure decreases so does the density. Of course the lowering density means pressure falls even quicker.
2006-11-13 03:22:11 · answer #5 · answered by Anonymous · 0⤊ 0⤋
i think you ask the question wrongly.you should ask"why doesthe atmospheric prssure decreases with height.
atmospheric pressure is the weight or load of air acting on everithing .Now as all of us know,weight is the gravitational force acting on an object.so ,as the height increases,the "weight decreases"or the atmospheric pressure decreases.this is because the strenght of gravitational force decreases.
2006-11-13 00:49:23 · answer #6 · answered by mr.maths 2 · 0⤊ 0⤋
The further you get from the surface of the earth, the lesser the gravitational pull of the earth. Therefore less "air" at higher elevations.
2006-11-13 00:41:19 · answer #7 · answered by tmarschall 3 · 0⤊ 0⤋
As you go up there is less air above you. Therefore their is less weight of air. Barometric pressure decreases. Because of this the molecules spread out also.
2006-11-13 00:49:25 · answer #8 · answered by science teacher 7 · 0⤊ 0⤋
because there is lesser gravitational attraction at the very top...
2006-11-13 01:25:22 · answer #9 · answered by Anonymous · 0⤊ 0⤋
Because of the gravitational pull!!!!!!!₹!!!!)¡¡!!!!!!¡!!!!!!
Beta
2014-09-12 20:18:04 · answer #10 · answered by Anonymous · 1⤊ 0⤋