Boomerang are V-shaped devices, opening at an angle between 900 and 1600, depending on their use. There are two types of boomerangs-the returning and the non-returning. The best known type is the returning. When thrown correctly, this type returns to the thrower without his moving and so is used mainly for fun on in sports, since it cannot be aimed accurately. It is the the non-returning type, which is not as bent as the returning type, that has been used as an accurately aimed weapon for centuries, especially by the aborigines, the original inhabitants of Australia.
The returning boomerang comes back to the thrower because of its shape and size, and the manner it is thrown in, and also because of air pressure. The bend in the middle gives it the shape of an aeroplane’s wings. The topside of the wing is curved and the underside is flat, with one thick edge and one thin edge. The thrower grips one wing-tip and throws. As the boomerang flies it spins wing over wing. The air pressure below the boomerang is greater than the air pressure above it, and thus keeps it travelling. First it flies forward, then curves to one side to return to the thrower. An experienced boomerang thrower can send a boomerang 50 meters before it turns to come back!