A ball is a round, usually spherical but sometimes ovoid, object with various uses. It is used in ball games, where the play of the game follows the state of the ball as it is hit, kicked or thrown by players. Balls can also be used for simpler activities, such as catch, marbles and juggling. Balls made from hard-wearing materials are used in engineering applications to provide very low friction bearings, known as ball bearings. Black powder weapons use stone and metal balls as projectiles.
Although many types of balls are today made from rubber, this form was unknown outside the Americas until after the voyages of Columbus. The Spanish were the first Europeans to see bouncing rubber balls (albeit solid and not inflated) which were employed most notably in the Mesoamerican ballgame. Balls used in various sports in other parts of the world prior to Columbus were made from other materials such as animal bladders or skins, stuffed with various materials.
As balls are one of the most familiar spherical objects to humans, the word "ball" is used to refer to, or to describe, anything spherical or near-spherical.
Other articles related to "ball, balls":
... The Quarter seam is the tiny seam which runs around a cricket ball at 90 degrees to the large, raised seam ... in order to create conventional swing when the ball is relatively new, more recently, an understanding has evolved that the quarter seam can be lifted on one side, presumably with the thumb or ... over alters the balance of air pressure surrounding the ball as it travels through the air and help it reverse ...
... paradoxical decomposition of S2 then yields a paradoxical decomposition of the solid unit ball minus the point at the ball's centre (this center point needs a bit more care, see below) ... many such points, and like the point at the centre of the ball, it is possible to patch the proof to account for them all (see below) ...
... geometry which states the following Given a solid ball in 3‑dimensional space, there exists a decomposition of the ball into a finite number of non-overlapping pieces (i.e ... together in a different way to yield two identical copies of the original ball ... of the theorem implies that given any two "reasonable" solid objects (such as a small ball and a huge ball), either one can be reassembled into the other ...
... Computed tomography of a football (soccer) (Video) Baoding balls Baseball Basketball Billiard balls Bowling ball (and pin) Lacrosse ball Cricket ball Golf ball next to a hole Rugby union ...
... Using the Banach–Tarski paradox, it is possible to obtain k copies of a ball in the Euclidean n-space from one, for any integers n ≥ 3 and k ≥ 1, i.e ... a ball can be cut into k pieces so that each of them is equidecomposable to a ball of the same size as the original ... These results then extend to the unit ball deprived of the origin ...
Famous quotes containing the word ball:
“I don’t like comparisons with football. Baseball is an entirely different game. You can watch a tight, well-played football game, but it isn’t exciting if half the stadium is empty. The violence on the field must bounce off a lot of people. But you can go to a ball park on a quiet Tuesday afternoon with only a few thousand people in the place and thoroughly enjoy a one-sided game. Baseball has an aesthetic, intellectual appeal found in no other team sport.”
—Bowie Kuhn (b. 1926)
“It may be possible to do without dancing entirely. Instances have been known of young people passing many, many months successively, without being at any ball of any description, and no material injury accrue either to body or mind; Mbut when a beginning is made—when felicities of rapid motion have once been, though slightly, felt—it must be a very heavy set that does not ask for more.”
—Jane Austen (1775–1817)
“The symbolic view of things is a consequence of long absorption in images. Is sign language the real language of Paradise?”
—Hugo Ball (1886–1927)