system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do boomerangs come back?
gpt
A boomerang is shaped like a small wing. The side that is spinning forwards goes "faster" in comparison to the air it moves through than the side that is spinning backwards. The faster side generates more lift due to the faster airspeed and tries to rotate the boomerang around the axis that runs along the direction you threw it, or turn over. Because it's spinning, it also fights turning over by turning around to conserve angular momentum (this is related to the same phenomenon that helps keep you upright while your bicycle is moving even though it's hard to balance on a stationary bicycle). You could feel the same forces at work by spinning a fairly large fidget spinner in your hand, sitting in an office chair, and trying to turn it over.