Some facts about Balls

  One of man's oldest toys is a simple, round object called a ball. The first balls were rounded stones, which were rolled or tossed. Thousands of years ago, balls were used as weapons. They were thrown at enemies and game animals.
  Balls are rolled, tossed, and hit in many games. Baseball, soccer, basketball, tennis, bowling, football,  volleyball, billiards, golf, and many other games use balls of some kind. We usually think of a ball as perfectly spherícal, or round. This is not always so. A football, for example, is oval instead of round.
Balls can be made of almost any material, including snow. The Aztec and Mayan Indians played an old game like basketball with a rubber ball. American Indians played lacrosse and other games with balls made of animal hides. Animal skins still provide the covering of some kinds of balls. Horsehide is the outer surface of most baseballs. A football is often referred to as a "pigskin," although pigskin is no longer used in footballs. Plastics are widely used in making different kinds of balls. Others are made of solid wood and rub¬ber. Rubber balls are lots of fun to play with, because they bounce.
  There are many sizes and weights of balls. Maybe you have seen a big, heavy, sand-filled "medicine" ball in a gym. Compare that with a lightweight ping-pong ball, which you can blow across a table with a deep breath. One of the smallest balls is the kind used in a game of jacks. It must be tiny enough to fit in a child's hand. It must also be bouncy enough to give the player time to pick up the jacks.