What makes a boomerang return to the thrower?
A boomerang is in fact simply two wings joined together in a single unit. The wings are set at a slight tilt and they have an airfoil design – they are rounded on one side and flat on the other, just like an airplane wing. This design gives a wing lift: the air particles move more quickly over the top of the wing than they do along the bottom of the wing, which creates a difference in air pressure. The wing has lift when it moves because there is greater pressure below it than above it. The two wings are arranged so that the leading edges are facing in the same direction, like the blades of a propeller. At its heart, a boomerang is just a propeller that isn’t attached to anything. A propellor spins, and on a boomerang, whichever wing is at the top of the spin at any one time ends up moving in the same direction as the forward motion of the throw, while whichever wing is at the bottom of the spin is moving in the opposite direction of the throw. This means that while the wing at the top
