Pair of Smashing Steel Spheres – Energy Transfer Balls
by American Scientific

When two 8oz, 1.5-inch diameter, steel spheres are smashed together, enough heat is generated at the point of contact to burn a hole in a piece of ordinary paper. This amazing demonstration graphically illustrates the conversion of mechanical energy into heat energy, and although there are no flames, a charred hole will appear along with a faint odor of burnt paper. This amazing demonstration visually illustrates the conversion of kinetic energy into heat energy. The kinetic energy of the two heavy moving spheres is converted into heat at the point of collision. Many believe that at the point of collision, a shock wave travels through the paper or foil. Under a microscope, you can see little specks of carbon and ripples in the paper similar to the ripples in aluminum foil. This kit includes a pair of 1.5″ steel spheres, and a teacher’s guide.

Procedure:

1. Place a sphere in each hand and hold your hands about 1-meter apart. Then quickly move your hands together until the steel spheres collide and bounce off. Repeat with an assistant holding a piece of paper vertically at the point of collision. Smell and examine the paper. If a microscope is available, one can see burnt specks of carbon and concentric ripples in the paper.
2. Repeat with a piece of aluminum foil instead of the paper. A number of concentric rings are observed in the foil.
3. Repeat the experiment with different types of paper, different thicknesses, or multiple layers. Try to avoid papers that have wax coatings (like manila folders), as the wax will prevent a hole from forming.