Spinning Fountain

So the sun finally came out, but the sprinkler has lost its luster and you still want water fun. What’s a kid to do? Try this on for size and see what you think.

Materials:

Empty half-gallon paper milk carton

Nail

2-foot long string

Tree branch

Directions:

1. Get an empty half-gallon paper milk carton. Use a nail to punch a hole in each left-hand corner of the carton, close to the bottom. Punch another hole in the top flap of the carton. An adult may have to help you punch the holes.



2. Tie one end of a 2-foot-long string through the hole in the top of the carton.



3. Tie the free end of the string around a tree branch so that the carton is dangling in the air.



4. Ask two friends to cover the holes in the bottom of the carton with their fingers. Use a hose or pitcher to fill the carton with water.



5. Ask your friends to remove their fingers from the carton. What happens when water squirts out of the holes?

Action, Reaction, Results:

When water squirted out the carton spun around. This happened because of Newton’s third law of motion (every action has an equal and opposite reaction). As water spurted out of the holes, it pushed back on the carton. This made the carton twirl in the opposite direction. What happens if you change the placement of the holes? Does the size of the hole matter?