Lesson Plan Title : Using a Lock to Move a Boat

Age Range: Grade 3 through Grade 5 (Elementary)

Overview and Purpose: How do large, heavy water vessels pass through the shallow parts of a river? Locks! The following experiment will give students a better understanding of how this happens.

Objective: The student will be able to demonstrate how a lock works.




Shallow pans

Thin, small pieces of wood

Something small that floats (i.e. feather, piece of wax paper)


Have the students demonstrate how a lock works by creating miniature ones out of play-doh and wood. Divide students into groups of three and give them one or two containers of play-doh, wood, a shallow pan, and a cup of water.

Have students make a large, oblong or rectangle bowl that is flat on the bottom. Have them make slots that the wood can slide into after the play-doh dries. (If they make the bowl slightly smaller than the width of the wood, they can slide the wood in and it will make the ridges naturally. They may need to make the sides of the slots a little bigger though to hold the wood upright. If they press the wood down slightly it will make a slot in the bottom of the bowl also.) When they slide the wood in, this will have three separate chambers. In the last chamber have them make the walls higher and the floor start just below the rest of the bowl.

Let the play-doh dry overnight without the wood in it. The next day have the students put the bowl in a shallow pan and put the wood in place. They can pour the water in the highest end and place the feather in the middle section. Have one student lift the gate out of its track while another student pours the water slowly into the high section to represent the river flowing. The water in the middle will rise until it is even with the high side. Then the feather can float across.

To lower the lock, have the students place the feather in the middle section and slowly lift the wood out of its track on the lower side. The water will flow until it is equal in both sections and the feather can float across.

Wrap Up:

Have the students map the largest river near your school. How many locks and dams are on the river? How do locks relate to dams in size, location and use? How far could they go on an inland-water journey?