Kim Spector, age 1 3, of Richmond, Va  for his question:

Why must the Panama Canal have locks?

The Panama Canal is a man made finger of water connecting the Atlantic and the Pacific Oceans, The two oceans, of course are at sea level. The distance from ocean to ocean is about 50 miles, but 32 miles of the journey is across the surface of Gatun Lake, And this man made lake is 85 feet above sea level.

The building of the canal was one of the greatest engineering jobs of all time. Great ocean liners must be lifted 85 feet above sea level to cross the lake and then lowered again to sea level on the other side. The job is done with stairways of locks. The locks are in pairs to take care of shipping traffic to and fro. Three locks lift a ship up 85 feet to the level of the lake and three more let it down again to sea. level.