Q. Why do baseballs float?
A. They're hard (ask anyone who's felt a Roger Clemens beanball). They're heavy (a regulation baseball weighs a solid 5� ounces). And unlike footballs and basketballs, they're not filled with air. So when Barry Bonds hits a tater into McCovey Cove, as he did last week when he smacked his 500th career homer, why doesn't the pill disappear into the depths? Turns out a baseball, which is made up of a cork-and-rubber center, 219 yards of wool yarn, 150 yards of cotton string and a cowhide cover, isn't dense enough to sleep with the fishes. According to Robert Adair, professor emeritus of physics at Yale and author of The Physics of Baseball, for an object to sink it must weigh more than the fluid it displaces. A baseball, like a steel battleship, weighs less than the displaced water. "Most organic things float," says Adair. "They're not dense enough to sink. A baseball is mostly organic materials." Good news for all those souvenir-seeking McCovey Cove sailors.