Why does the air we breath float on Earth?

In summary, the conversation discusses the reason why air on Earth does not all sink to the ground, despite gravity being present. The lighter gases, such as Helium and hot air, float due to their lower density compared to the air around them. However, even the denser gases that we breathe, such as oxygen, do not completely sink to the ground due to the weak force of gravity. This is similar to how water in a swimming pool does not all gather at the bottom, but rather distributes itself throughout the pool. The mixing of gases in the atmosphere is also influenced by turbulence and diffusion at different altitudes. Ultimately, the reason why Earth's atmosphere does not separate into layers of different gases is due to the relatively weak force of
  • #1
themadquark
22
1
Why does air on Earth float? Obviously, lighter gases such as Helium and even hot air will float due to having a lowed density than the air around it. Why is it though that the base higher density gases that we breath float rather than sink to the ground? My belief is that gravity is simply too weak to hold the O2 and the other gases completely to the ground.
 
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  • #2
Air does sink to the ground. Put your head near the ground and breathe in - it still works down there!

Think of a swimming pool. Down at the bottom there's some water, and at the top there's water too. The water at the top of the pool isn't "floating", there's just not enough room for it all to be at the bottom.

On Earth, we're swimming around in a bunch of gases. Some gas at ground level, some is up higher, all in one giant pile. There isn't enough room for it all to be exactly 0 cm from the ground, so it piles up.
 
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  • #3
Perhaps the question the OP is asking is...

Why doesn't the atmosphere separate out into layers of Oxygen, Nitrogen etc.
 
  • #4
Let's let the OP explain what he means rather than start another long thread guessing.
 
  • #5
Gasses mix due to turbulence below 100 km and diffusion at high altitudes. A NOAA study of composition of the atmosphere versus altitude can be found in http://ruc.noaa.gov/AMB_Publications_bj/2009%20Schlatter_Atmospheric%20Composition%20and%20Vertical%20Structure_eae319MS-1.pdf
 
  • #6
Please, let's let the OP explain what he means rather than start another long thread guessing.
 
  • #7
Air doesn't all sink to the ground for the same reason you don't. Gravity on Earth isn't strong enough to compact it that much. The layer of atmosphere we live in is made up of gasses that weigh more than those in higer layers. If Earth's gravity was that strong the Earth would be a star instead of a planet.
 
  • #8
This thread is 9 months old and the OP never returned to it. Locked.
 

1. Why does air float on Earth?

The air we breathe floats on Earth due to the force of gravity. Gravity pulls all objects towards the center of the Earth, including the air molecules. However, the air is less dense compared to other objects on Earth, such as water or solid materials, so it rises and stays in the upper atmosphere.

2. How does air stay in the Earth's atmosphere?

Air stays in the Earth's atmosphere because of the Earth's gravity. The Earth's gravity is strong enough to keep the air molecules from escaping into space. Additionally, the Earth's atmosphere is made up of different layers with varying densities, and the air molecules are constantly moving and colliding, which helps to keep them in place.

3. Why doesn't the air fall to the ground?

The air doesn't fall to the ground because it is constantly being pushed up by warmer air and pulled down by colder air. This creates a balance, known as atmospheric pressure, which keeps the air floating in the Earth's atmosphere. Additionally, the Earth's gravity also plays a role in keeping the air from falling to the ground.

4. Can air float on other planets?

Yes, air can float on other planets as long as the planet has an atmosphere and gravity. However, the composition and density of the air may differ depending on the planet. For example, the air on Mars is much thinner than the air on Earth due to its lower gravity and lack of a strong magnetic field to hold onto its atmosphere.

5. How does air pressure affect the floating of air on Earth?

The air pressure plays a crucial role in the floating of air on Earth. Air pressure is the force exerted by the weight of the air above a certain point. As the air molecules move and collide, they create pressure that helps to keep the air floating in the Earth's atmosphere. Changes in air pressure can also affect the movement and behavior of air on Earth.

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