Summer vacation is right around the corner and kids will want to play! If parents are searching for fun (and educational!) projects to occupy the time, then look no further than Sean Connolly’s The Book of Potentially Catastrophic Science. It’s the best of both worlds—exciting experiments backed by real scientific principles. Using common items found around the house or outdoors, these experiments will encourage young minds….

With a long weekend right around the corner, why not give one of the projects a whirl. This one retraces Isaac Newton’s steps – just make sure it’s performed outside, it gets messy!

Newton’s Third Law of Motion: Experiment #14

This is a great way to see equal and opposite forces in action (and reaction). When you let go of the holes in the carton, the water goes shooting out. That is the first force. It also pushes back on the carton with equal force, just as the fuel burning out of the back propels a rocket forward. But because you are holding the carton in place from above, the linear (straight-line) force becomes converted into a rotational (spinning) force.

Materials:
Empty half-gallon beverage carton
Pencil
Scissors
String
Friend to help and observe
Water

1. Use a pencil to jab a hole in the bottom-left corner of each side of the carton.

2. Make a similar hole in the center of the top flap. (This might be a little too tough for the pencil, so you can use the scissors.)

3. Cut a 2-foot length of string and tie one end through the hole in the flap.

4. Hold each of the four bottom holes while your friend fills the carton with water and holds the free end of the string.

5. Get your friend to hold the string up and away from herself, and let go of the four holes.

6. Water should rush out of the holes and the carton should spin around until the water runs out.