Jon Anderson, age 13, of Duluth, Minn., for his question:

WHAT MAKES A BOOMERANG RETURN?

Many stories are told in Australia about the workings of the boomerang. A complete fable, unfortunately, is the one about an aborigine being able to throw a boomerang so that it hits an enemy hiding behind a tree, and then having the weapon return to the thrower. Also untrue is the story of the

native who throws the boomerang with his back to the object he wishes to hit.

Many strange stories that are told about boomerang throwing in Australia sound as if they are fiction but are actually true. For example, it is possible for a native to be so expert that he can make his boomerang pass behind him after a short preliminary flight in front.

If a boomerang is expected to hit an object, this happens during the first part of the weapon's flight path  when it is going straight and has just been thrown by the expert. It turns for a return flight only if the object is missed.

Because the boomerang is flying through air, right from the start of its flight, it is meeting resistance and is being slowed down. It is shaped so that the air resists one part of it more than another, so that it has to travel in a curved path after its speed has slowed down below a certain rate. As it travels in this curve, it more or less comes back to the place from which it was launched.

Studies have been made in attempts to find out why boomerangs must always be a certain shape and why they must have a certain weight and size. The difficult questions have never been completely answered.

There are different types and sizes of boomerangs in Australia, although all follow the same basic pattern. There are some which are heavy and used for fighting at close quarters, while others are light and designed for hurling at game at a great distance.

Boomerangs that return to the thrower  the kind that are best known throughout the world  are actually often called play boomerangs. The Australian aborigines who use them well are skilled in the art of having them do lots of tricks. It's almost like show business.

Weapons very similar to the boomerang, but unable to make a return flight, were used in ancient Egypt and by the Hopi Indians in Arizona.

The Australian play boomerangs have special curved blades and are usually quite flat on one side and slightly rounded on the other. The power of return seems to be associated with a very slight twist in the weapon.