Timmy Emrich, age 7, of Polkton, N.C., for his question:

HOW HIGH IS A PITCHER'S MOUND?

Around regulation baseball parks, such as those used in the major leagues, you will find walls and fences that vary from ballpark to ballpark. The size and shape of the infield, however, must be exactly the same in every city. The baseball field can then be covered by either natural grass or artificial turf, with the sections between the bases covered by dirt.

A baseball's infield is actually a square area with a base at each corner. Home plate is at one corner, with first base, second base and third base following in counterclockwise order. Between each of the bases is 90 feet.

First, second and third bases are covered with white canvas bags filled with kapok that measure 15 inches square and between three and five inches thick. Each base is carefully anchored to the ground.

Home plate is a chunk of white rubber sunk into the ground so it is level with the field's playing surface. The front of the plate that faces the infield is 17 inches wide. It then tapers back to a point.

Sixty feet and six inches from home plate, heading toward second base, is the pitcher's mound. The area, which is actually in the center of the infield, measures 18 feet in diameter. It slopes upward and at its center is 10 inches higher than the rest of the infield.

In the center of the pitcher's mound is a piece of white rubber 24 inches long and six inches wide. Sunk into the ground, the slab is called either the pitcher's plate or the rubber.

Standing on his elevated mound, the major league pitcher throws a baseball that may travel toward the batter at a speed close to 100 miles per hour.

The ways pitchers can throw the ball during a baseball game vary widely. In a right handed pitcher's typical delivery he will start with his right foot on the pitcher's plate and both of his hands holding the ball above his head. He will next lift his left leg almost belt high and then push his entire body forward using the plate for leverage. The ball is thrown overhand and the pitcher follows through by stepping forward on the mound

A curve ball, when delivered by a right handed pitcher, will break sharply to the left and downward as it reaches the batter. A left handed pitcher's curve breaks to the right and downward. A slider looks a lot like a curved ball, but it seems to "slide" rather than break sharply, and it does not move downward. Pitchers also deliver knuckle balls, sinkers and screwballs.