Hopper Popper

Concept Overview

1. Transformation of elastic potential energy to kinetic energy
2. Conservation of Energy

Lecturer Procedure

Steps to Follow

1. Turn popper inside out.
2. drop onto bench from a low height (1-2 feet) with the rounded end pointed up.

Expected Result

Popper rebounds to a height significantly greater than its drop height.

Historical References; Taken from original work of Percy H. Carr, 1970 

“Because of its initial curvature in manufacture, a hollow rubber hemisphere that is turned inside out stores a lot of energy. You can easily see this by popping the hemisphere from one equilibrium configuration to the other, and seeing that one popping direction is a lot more vigorous than the other. When the inside-out hemisphere is dropped it pops into the lower-energy configuration with a gain of kinetic energy."

Video Demonstration

There is no audio with this recording.