It seems to me that space doesn't have any/much air, and if my bottle is full of air, when I open it, where does the air go?
[Physics] If I take a bottle of air into space, and open it, where does it go
airpressurespacethermodynamics
airpressurespacethermodynamics
It seems to me that space doesn't have any/much air, and if my bottle is full of air, when I open it, where does the air go?
Best Answer
The gas molecules in your bottle of air aren't just sitting still, they're moving around in random directions. From memory, the speed of oxygen and nitrogen molecules at room temperature is around 500 meters per second.
When the bottle is closed, the air molecules hit the walls and lid of the bottle and bounce back, so the air stays in the bottle. If you take the lid off, then because the gas molecules are moving around randomly, and at high speed, pretty soon most of them will have escaped through the opening.
Now, if you take the lid off the bottle here on earth there are air molecules buzzing around in the atmosphere outside the bottle, so at the same time as the air molecules in the bottle escape, air molecules from the amosphere enter the bottle. The end result is the bottle stays full of air.
If you take the lid off in space the air molecules in the bottle escape, but there aren't any air molecules in space to replace them, so the bottle will very quickly be empty. The air molecules that were in the bottle will be heading off into outer space at a few hundred meters per second.