# TED Conversations

United Nation member

This conversation is closed. Start a new conversation
or join one »

## If gas particles are a lightweight, why don't they stay on the same level as air? Why do they fly up?

Gas particles fly up into the air to get to the last level of air. This means there is another force to pull them up, and if there is no atmosphere they will leave earth. What if that force can do the opposite of the magnetic field of our earth?

Topics:
0
Share:
• #### Humble Polymath

• +1
Oct 15 2011: Upthrust/bouyancy has been known since the time of Archimedes. It is simply displacement based on density. Within a fluid system, denser things fall and relatively less dense things rise to the level of the system that matches their density. Available volume, pressure and temperature all affect density.

Gerald are you a troll? I hope so ...

• 0
Oct 15 2011: Hi Humble, thanks for your comment that applied for liquids how it's applied on Gas, please can you explain that.
• #### Humble Polymath

• +1
Oct 22 2011: Bilal. I did not say liquid, I said fluid. Both liquids and gases are fluids. Fluids have no fixed shape, and their density is influenced by the volume they take up, the pressures exerted upon them, and their temperatures. Google 'fluid mechanics' or 'the physics of fluids' and I am sure there are many sites that can explain everything you want to know. Good luck.
• #### Douglas Bell

• 0
Oct 30 2011: Hi Bilal,

You'll need to work at the molecular level, not at the atomic level. Our atomosphere is about 80% paired Nitrogen atoms, about 20% paired Oxygen atoms, and a few percent of everything else. Any molecule that is lighter than the N2 - O2 in the atmosphere is going to float upwards in the same way that oil is pushed upwards in a bowl of water. So, for example, Helium (which is very light) appears to rise in the atmosphere. Other gases, like propane, are heavier and sink to the lowest level available.

Of course, this only applies to molecules that are gaseous in our normal conditions. You won't find any gaseous iron (Fe) in the air for the simple reason that iron isn't gaseous at these conditions. (Actually, I'm not sure if there are ANY conditions where iron is a stable gas, but that's for another conversation).

Best wishes,
Doug Bell
• #### Gerald O'brian50+

• 0
Oct 15 2011: This force is called upthrust buoyancy. It's a new thing in physics. Nobody knows yet how it works, but we've got a name to it, as a start. Something to do with density of materials...