What does a lock do on a canal?

Locks work by taking the advantage of water running down hill. The water is raised by closing the downstream pipe, filling up the box. Anything floating in the box will raise. Closing the upstream...

Locks are only needed when the ships need to be raised and lowered in altitude because of the terrain the canal crosses.

Locks on canals exist because you need level water to be able to boat, sail or barge from one point to another. Unlike a road, a river or a canal cannot have a hill. Hills on water are called rapids...

No. Most, but not all, other canals have canal locks. Most canals are not built on flat land. Another without locks is the Corinth Canal.

no