Superhero Strength

What You Need:

• Adult volunteer (the stronger, the better!)

What You Do:

1. Ask the adult helper to stack one fist on top of the other and extend their arms until his elbows are straight. Feel free to have them growl, or make noises indicating how strong they are!
2. Have your child place two fingers on the top fist, and two on the bottom fist. When they're ready, have them quickly push the fists in the opposing directions.
3. They'll notice how easy it was to separate the strong fists, and may not believe they could possibly be that strong. Have them try it one more time so as to confirm their power.
4. This time, have the adult volunteer, push their fists together even more fervently than before and have your child repeat the experiment.
5. This was even easier! Why?

Explain to them that when the fists are stacked, pushing together, it creates a vertical force. Vertical forces can only push up and down, not side to side. So, when they pushed side to side with their super strength, (or horizontal force), they disabled the balance of the vertical force, making it impossible for the adult to keep their fists stacked.