Will Siphons Function in a Vacuum Without Air Pressure?

[moronthat]

The Oxford dictionary is about to change its definition of a siphon to remove the reference to air pressure as being required. Will a siphon work in a vacuum?

 

[mgb_phys]

No the water will boil.

Although a siphon doesn't run on air pressure, air pressure still has an effect.
The main limit on a siphon is that the head of water (the distance between the surface of the upper level and the top of the siphon hoop) can't be more than the height of a column of water supported by atmopsheric pressure (ie 9.8m)
At lower pressures the maximum height of the loop will decrease and in vacuum it reaches 0

 

[moronthat]

I didn't say the liquid was water.

 

[mgb_phys]

I didn't say the liquid was water.

Doesn't matter - it will still have a finite vapour pressure.
The mechanism of a siphon isn't air pressure - but you can't have a loop height more than the maximum column of the liquid that can be supported by air pressure.

 

[cesiumfrog]

This topic is also being discussed simultaneously https://www.physicsforums.com/showthread.php?p=2716185".