A siphon is a simple device used to move liquid from one container to another, typically against the force of gravity. It consists of a tube that is filled with liquid, with one end placed in the source container and the other end positioned lower in the receiving container. When the liquid is initially drawn into the tube, gravity and atmospheric pressure work together to keep the flow going. Siphons are commonly used in various applications, such as draining aquariums, transferring liquids in laboratories, and even in gardening for irrigation. The principle behind a siphon relies on the difference in height between the two containers, allowing the liquid to flow continuously until the source is empty or the height difference is eliminated.