Non-conservation of mechanical energy in spring-launching toy poppers

Abstract

The law of conservation of mechanical energy states that, in an isolated system, mechanical energy remains constant as energy transforms between its kinetic and potential form without loss. This experiment investigates if energy is conserved in a 0.0055 kg spring-launching toy popper. When compressed, the toy stores elastic potential energy that is then converted to kinetic energy as the toy is released. The kinetic energy is then converted to gravitational potential energy as the toy ascends. A two-tailed paired t-test comparing the initial kinetic energy and gravitational potential energy at maximum height across ten repeated trials of the same popper yielded a statistically significant difference from zero. This result appears to suggest that mechanical energy was not fully conserved, but a more likely explanation is that we did not account for the presence of non-conservative forces such as air resistance during launch.