Ball
A ball is a round object (usually
Although many types of balls are today made from
As balls are one of the most familiar spherical objects to humans, the word "ball" may refer to or describe spherical or near-spherical objects.
"Ball" is used metaphorically sometimes to denote something spherical or spheroid, e.g.,
Etymology
The first known use of the word ball in English in the sense of a globular body that is played with was in 1205 in
History
A ball, as the essential feature in many forms of gameplay requiring physical exertion, must date from the very earliest times. A rolling object appeals not only to a
Ancient Greeks
Among the ancient Greeks, games with balls (σφαῖραι) were regarded as a useful subsidiary to the more violent athletic exercises, as a means of keeping the body supple, and rendering it graceful, but were generally left to boys and girls. Of regular rules for the playing of ball games, little trace remains, if there were any such. The names in Greek for various forms, which have come down to us in such works as the Ὀνομαστικόν of Julius Pollux, imply little or nothing of such; thus, ἀπόρραξις (aporraxis) only means the putting of the ball on the ground with the open hand, οὐρανία (ourania), the flinging of the ball in the air to be caught by two or more players; φαινίνδα (phaininda) would seem to be a game of catch played by two or more, where feinting is used as a test of quickness and skill. Pollux (i. x. 104) mentions a game called episkyros (ἐπίσκυρος), which has often been looked on as the origin of football. It seems to have been played by two sides, arranged in lines; how far there was any form of "goal" seems uncertain.[4] It was impossible to produce a ball that was perfectly spherical;[6] children usually made their own balls by inflating pig's bladders and heating them in the ashes of a fire to make them rounder,[6] although Plato (fl. 420s BC – 340s BC) described "balls which have leather coverings in twelve pieces".[7]
Ancient Romans
Among the
Modern ball games
The various modern games played with a ball or balls and subject to rules are treated under their various names, such as polo, cricket, football, etc.[4]
Physics
In sports, many modern balls are pressurized. Some are pressurized at the factory (e.g. tennis, squash (sport)) and others are pressurized by users (e.g. volleyball, basketball, football). Almost all pressurized balls gradually leak air. If the ball is factory pressurized, there is usually a rule about whether the ball retains sufficient pressure to remain playable.[8][9] Depressurized balls lack bounce and are often termed "dead". In extreme cases a dead ball becomes flaccid. If the ball is pressured on use, there are generally rules about how the ball is pressurized before the match, and when (or whether) the ball can be repressurized or replaced.
Due to the ideal gas law, ball pressure is a function of temperature, generally tracking ambient conditions. Softer balls that are struck hard (especially squash balls) increase in temperature due to inelastic collision.
In outdoor sports, wet balls play differently than dry balls. In indoor sports, balls may become damp due to hand sweat. Any form of humidity or dampness will affect a ball's surface friction, which will alter a player's ability to impart spin on the ball. The action required to apply spin to a ball is governed by the physics of
Round balls
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Footballfrom association football (soccer)
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Bowling ball (and pin)
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Rubber band ball
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Table tennis balls
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Sponge Ball
Prolate spheroid balls
Several sports use a ball in the shape of a
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Rugby union ball.
See also
- Ball (mathematics)
- Buckminster Fullerene"Bucky balls"
- Football (ball)
- Hockey puck, can also spin, bounce, and roll
- Kickball
- Marbles
- Penny floater
- Prisoner Ball
- Shuttlecock
- Super Ball
References
- ^ "Code of Federal Regulations: 1985–1999". U.S. General Services Administration, National Archives and Records Service, Office of the Federal Register. 5 November 1999. Archived from the original on 7 November 2017. Retrieved 5 November 2017 – via Google Books.
- ^ πάλλα Archived 2015-09-24 at the Wayback Machine, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus
- ^ σφαίρα Archived 2017-03-20 at the Wayback Machine, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus
- ^ a b c d Chisholm, Hugh, ed. (1911). . Encyclopædia Britannica (11th ed.). Cambridge University Press.
- ^ Gershon, Livia (October 21, 2020). "These Hair-Filled Leather Pouches Are the Oldest Balls Found in Eurasia". www.smithsonianmag.com. Smithsonian Institution. Retrieved November 2, 2020.
- ^ ISBN 978-1-4549-0908-8.
- ^ Plato (1909). "Phædo (Dialogues of Plato)". In Charles W. Eliot (ed.). The Apology, Phædo and Crito of Plato – The Golden Sayings of Epictetus – The Meditations of Marcus Aurelius. The Harvard Classics. Vol. 2. Translated by Benjamin Jowett (1st ed.). New York: P. F. Collier and Son. p. 107. Retrieved May 16, 2020.
- ^ "Preparing the Footballs for NFL Games | NFL Football Operations". operations.nfl.com. 2015-08-10. Retrieved 2023-11-01.
- ^ LaCombe, Ronnie. "How much air can fit in a basketball?". Columbia Daily Tribune. Retrieved 2023-11-02.
External links
- The dictionary definition of ball at Wiktionary