Sports
Conservation of Angular Momentum in Figure Skating
Quick fact
A figure skater can increase their rotation speed by up to six times simply by pulling their arms closer to their body.
Why this is interesting
Have you ever watched a figure skater spin faster as they pull their arms in? It’s not magic—it’s physics.
Read the full explanation
Understanding Conservation of Angular Momentum in Figure Skating
When a skater spins, they rotate around their own axis. By bringing their arms inward, they change the distribution of mass, which affects how fast they spin—this is due to angular momentum being conserved unless acted upon by an external force.
A deeper explanation
Angular momentum is the rotational equivalent of linear momentum. It depends on both the speed of rotation and the distribution of mass around the axis. When a skater pulls their arms in, they reduce their moment of inertia (resistance to change in rotation), which causes them to spin faster to conserve angular momentum. This principle is central to understanding how objects rotate under different conditions.