A water clock is a clock that uses the flow of water to keep track of time. It is a type of clock that predates the mechanical clocks that we have today. A typical water clock works by having a container filled with water and a hole in the bottom. The hole is connected to a spout, which feeds into a container below. As the water flows out of the first container, it is measured by the time it takes to fill the container below. This allows the clock to keep track of the time, usually with fairly accurate results. Water clocks were used in ancient civilizations, and are still used in some places today.
