Hundreds of years before paddle boats traveled down the Mississippi during Mark Twain's time, Leonardo da Vinci designed his own hand-propelled paddle boat. These types of boats have transported people and supplies for centuries. Your students can make a self-propelled paddle boat using items including a milk carton, tongue depressors and rubber bands.

Prepare the Milk Carton

Give each student an empty, clean milk carton and have them cut it lengthwise. Tell them to keep the milk carton half with the part of the spout that hasn't been opened yet. Have them use a hole punch to carefully make a hole in the middle of the opposite sides of the carton.

Add the Pencil and Rubber Band

Have your students carefully push a pencil through the holes on both sides the carton, then place a rubber band vertically under the middle of the pencil. Have them hold the ends of the rubber band above the pencil and loop one end of the rubber band through the other end.

Secure the Rubber Band with a Paper Clip

Your students should punch a hole into the middle of the back/"bow" of the milk carton, then pull the rubber band through the hole in the bow, and secure it with a large paper clip. Have your students check the that the rubber band cannot pull back through the hole.

Attach the Paddles and Go

To attach the "paddles," ask your students to take a tongue depressor and attach it across one side of the pencil by wrapping it tightly with thick string (use an "X" pattern to wrap it). Have the students repeat this process with another tongue depressor on the other side of the pencil. Wind the paddles up by moving one tongue depressor backwards (try five times to start), then place your paddle boat into the water and let it go.