There are three types of balls to catch on defense. One of them is the ground ball. A ground ball is when the batter hits the ball so it is on the ground. This picture depicts a child properly fielding a ground ball. Once the ball is caught, the fielder must throw it to the base that the runner is going to so the fielder can get him out.

Another kind of ball for a fielder to catch is the fly ball. A fly ball happens when the batter hits the ball in the air. Then it is time for the fielder to get under the ball and catch it. When he catches it, the batter is automatically out.

The last kind of ball the batter can hit is the line drive. A line drive is what happens when the batter hits the ball in a straight line parallel to the ground, unlike the rising arc of a fly ball. Line drives are much harder to catch than a fly ball, because they are generally hit hard and high in the air, thus making the fielder jump.

If a fielder doesn't throw out the base runner, they can steal when the pitcher throws his next pitch. Stealing is when the runner tries to go from one base to another without getting thrown out by the catcher, but the catcher can throw him out at the base he's going to, and when the fielder he throws it to tags the runner, he's out.

The most important tool a fielder has at his disposal is the glove. Gloves are made of leather, have elongated fingers that allow the fielder a better shot at balls above his head, leather stitching that holds the fingers together to help fielders scoop ground balls, and a webbed basket to cradle the ball when caught. Older models of gloves had no webbing, no stitching, very little padding, and the fingers were not much longer than the ones on the fielder’s hand. Another kind of glove is the catcher’s mitt. It is thickly padded and has deep webbing for catching low pitches. Old catcher’s mitts were little more than leather pillows with no webbing or fingers.

The man who says if that runner is safe or out, the ball is fair or foul, or says if the fielder caught it or not, the big cohune, is the umpire. Umpires have many duties on the field. One of these duties is calling a base runner safe or out. Another duty is saying if a hit ball is fair or foul.