Home > Encyclopedia of Science > Lock

• History
• Construction and operation

A lock or water lock is an enclosed, rectangular chamber with gates at each end, within which water is raised or lowered to allow boats or ships to overcome differences in water level. Locks have a history of over 2,000 years, and although they are most often used by boats on canals, they also are used to transport massive ships between seas.

All locks operate on the simple buoyancy principle that any vessel, no matter what size, will float atop a large enough volume of water. By raising or lowering the level of a body of water, the vessel itself goes up or down accordingly. Locks are used to connect two bodies of water that are at different ground levels as well as to "walk" a vessel up or down a river's more turbulent parts. This is done by a series of connecting or "stair-case" locks. Locks contributed...