Hooked on Science: Balancing nails

Have you ever tried to balance 20 nails on one nail? With a little science, you can discover the center of gravity, or center of mass, and balance 20 nails on one nail.

Materials

* 21 7-inch gutter nails

* Wooden block

* Hammer

Instructions

STEP 1: Using the hammer, have an adult drive one of the nails into the center of the wooden block so the nail stands upright.

STEP 2: Lay another nail on a flat surface. Then place the nails, except for one nail, head to head, across the first nail. Lay the last nail, opposite of the first, on top of the nails.

STEP 3: Carefully and patiently pick up the nails and balance them on the nail sticking out of the wooden board.

Explanation

You were able to balance 20 nails on one nail due to the center of gravity, or the center of mass. The center of gravity, or the center of mass, is the one place you were able to balance the 20 nails on the one nail head. The mass of the nails is evenly dispersed and all the sides are in balance.

Jason Lindsey is a science outreach educator with Hooked on Science. Check out his website www.hookedonscience.org for webcasts and experiments.