Basically, because the atmosphere has weight. There would be no weight without gravity. Earth's gravity is pulling the atmosphere down toward earth's surface. We live on the surface, so the atmosphere pushes on us.
The original experiment that demonstrated this was a portable Mercury column.
If you have a large bowl full of Mercury (a liquid metal) and a 1 meter long glass tube open at one end, then you can make a simple barometer. First, completely fill the tube with mercury, and temporarily close of the open end of the glass tube with a fitted seal, so the glass tube will be completely full of mercury and closed at both ends. Then stand the inverted tube (with its sealed end in the bowl of mercury), and while the end of the tube is immersed in the mercury, remove the fitted seal, allowing the mercury trapped inside the tube to flow into the bowl. Some of the mercury will flow out of the tube into the bowl, but the air pressure will cause the remaining mercury remain in the tube up to a height of (about) 760 mm above the mercury level in the bowl. The volume in the tube above the column of mercury will be filled with a vacuum.
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If you were to then take your portable barometer on a hike up a mountain, you would notice that the volume of the vacuum in the tube would become greater, and the column of mercury in the tube become shorter. This is because the atmospheric pressure keeping the mercury up the tube is lower at a higher altitude.
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Note: Mercury is a dangerous substance and must be handled with care. The above experiment should not be attempted except under the supervision of qualified laboratory personnel.
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See the related link below.
The atmosphere is made up of gasses. Gasses are physical substances, and all physical substance has weight. The atmosphere is 25 miles thick, and that 25 miles thick layer of gasses presses down on earth with a weight of 15 lbs. per square inch. That's how atmosphere exerts pressure on the earth.
The force of gravity acts on the molecules of the atmosphere.
Because the atmosphere is over 100 kilometers high. :)
The atmosphere exerts pressure on various objects on the earth's surface. Air pressure is generally caused by the collision of the gas molecules with one another.
a barometer will tell you
The earths winds
the earths surface.
Pressure
The amount of pressure the atmosphere has varies from location to location. The internationally accepted standard atmospheric pressure is approximately 14.696 pounds per square inch (psi). This pressure is that which is measured for the altitude and location of Paris, France and is used in relevance.
air pressure
Air pressure is the pressure exerted from the atmosphere
the earths surface.
The earths winds
the earths surface.
Yes.
Pressure
Pressure
The atmosphere exerts pressure on various objects on the earth's surface. Air pressure is generally caused by the collision of the gas molecules with one another.
Yes. Atmospheric pressure is the pressure caused by air when it exerts pressure on the surface of earth.
The pressure is 17,8 atmospheres.
Air pressure is the amount of pressure exerted by Earth's atmosphere in a specific place, while altitude is the vertical distance of an object or place from sea level. Air pressure decreases as altitude increases, since there is less atmosphere to exert pressure.
You have a misconception... Pressure can be definitely exerted on gas. You might have heard of air compressor? Pneumatic cylinder? these elements exert pressure on air(Gas). Free air from atmosphere is sucked inside then pressurized & used for many applications. Please go through working principles of these elements.
Vapor materials exert their pressure in just about every direction