Question
Why does a siphon not work in vacuum?
Solution
The functioning of siphon is based on the atmospheric pressure. On sucking, the pressure of the air inside the siphon decreases and the atmospheric pressure on the liquid outside pushes the liquid up in the siphon. If there is vaccum, i.e., there is no atmospheric pressure, then there is no force on the liquid that can push the liquid into the siphon and siphon does not work.
