Why Skaters Turn Faster with Their Arms In

A skater, a person who moves on ice in special shoes, turns with both arms out. Then the skater brings the arms in and turns faster. The skater does not push on the ice again. Why does this happen?

Think of a line through the body, from head to foot. The body turns around this line. With the arms out, the hands are far from the line. It is harder to make the body turn faster or slower this way.

When the arms come in, they move closer to the line. The body does not get lighter. Its shape changes. If nothing outside the body changes the turn, this makes the skater turn faster. Putting the arms out again makes the turn slower.

Bringing the arms in takes work. The faster turn is not something the body gets for no work. Air and ice also slow the skater down. The turn cannot go on forever.