Alvin Goldstein, age 13, of Lyconia, N.H., for his question:

HOW HEAVY IS THE DISCUS USED IN DISCUS THROW

Discus throw is one of the oldest individual sports. It was a popular event with the ancient Greeks in their early Olympic Games. The Greeks considered the discus throwing champion to be the greatest athlete.

The ancient athletes threw a discus made of stone or metal. But \ the discus used today is a round wooden plate with a smooth metal rim. It weighs four pounds.

The modern discus is eight and five eighths of an inch in diameter and one and three fourths of an inch at the center, tapering slightly at the edge.

Athletes throw the discus from a circle that is eight feet two and one half inches in diameter. The discus thrower holds the discus in the palm of one hand, and ends of his fingers curling around the metal rim. He whirls his body in a complete turn to gather speed and power and then hurls the discus at the end of his second turn.

The athlete's fingertips spin the discus as it leaves his hand and it flies through the air in a fairly flat position.