Energy & Green Tech

Using crumpled graphene balls to make better batteries

Lithium metal-based batteries have the potential to turn the battery industry upside down. With the theoretically ultra-high capacity of lithium metal used by itself, this new type of battery could power everything from personal ...

Engineering

Making table tennis accessible for blind players

Table tennis has been played for decades as a more accessible version of tennis. The sport is particularly beginner-friendly while maintaining a rich level of competitive play. However, like many sports, it remains inaccessible ...

Computer Sciences

How a computer learns to dribble: Practice, practice, practice

Basketball players need lots of practice before they master the dribble, and it turns out that's true for computer-animated players as well. By using deep reinforcement learning, players in video basketball games can glean ...

Engineering

Engineers imitate human hands to make better sensors

An international research team has developed "electronic skin" sensors capable of mimicking the dynamic process of human motion. This work could help severely injured people, such as soldiers, regain the ability to control ...

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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