What principle does a siphon rely on to function correctly in plumbing?

A siphon operates based on atmospheric pressure and gravity, which are essential to its functioning. When a liquid is drawn through a tube elevated above the source, gravity plays a crucial role by pulling the liquid down on the discharge side of the siphon. This downward movement creates a difference in pressure between the liquid surface in the source container and the siphon exit, allowing atmospheric pressure to push the liquid up the tube from the source.

This principle explains why a siphon can effectively transfer liquid from one container to another, even when the destination is at a lower elevation, as long as the siphon’s outlet is lower than the liquid level in the source container. Understanding this relationship between atmospheric pressure and gravity is vital for maintaining efficient plumbing systems and ensuring proper drainage and water movement.