Psychology & Psychiatry

Who really hit the basketball out of bounds?

The shot clock reads 5, and a win forces a game 7. Two hands outstretched as the players—one in royal blue and yellow, the other black—hurtle towards the edge of the court. The ball sails out of bounds, and the play ends. ...

Neuroscience

Babies retain even detailed events during a nap

The brain is permanently exposed to new impressions. Even when sleeping, it does not rest and processes recent experiences. In very early childhood, it has been thought that sleep primarily promotes semantic memory. This ...

Neuroscience

How the brain regulates variability in motor functions

Anyone who has ever tried to serve a tennis ball or flip a pancake or even play a video game knows, it is hard to perform the same motion over and over again. But don't beat yourself up—errors resulting from variability ...

Pediatrics

Probability calculations—even babies can master it

One important feature of the brain is its ability to make generalisations based on sparse data. By learning regularities in our environment it can manage to guide our actions. As adults, we have therefore a vague understanding ...

Psychology & Psychiatry

Element of surprise helps babies learn

Infants have innate knowledge about the world and when their expectations are defied, they learn best, researchers at Johns Hopkins University found.

page 1 from 5

Ball

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.

This text uses material from Wikipedia, licensed under CC BY-SA