Billiards

Basketball is a team sport in which two teams of 5 players try to score points against one another by throwing or "shooting" a ball through the top of a basketball hoop under organized rules. A regulation basketball hoop is comprised of a rim 18 inches in diameter (45.72 cm) and 10 feet high (3.048 m) as well as a backboard. Basketball is one of the most popular and widely viewed sports in the world.[1] Points are scored by throwing (shooting) the ball through the basket from above. The team with more points at the end of the game wins, but additional time (overtime) may be issued when the scores of both teams are the same. The ball can be advanced on the court by bouncing it (dribbling) or passing it between teammates. It is a violation to walk with the ball or carry it. Disruptive physical contact (foul) is penalized, and free throws will be issued if an offensive player is fouled while shooting the ball. (violations). Through time, basketball has developed to involve many common techniques of shooting, passing and dribbling, as well as players' positions, and offensive and defensive structures. Typically, the tallest members of a team will play center or one of two forward positions, while shorter players or those who possess the best ball handling skills and speed, play the guard positions. While competitive basketball is carefully regulated, numerous variations of basketball have developed for casual play. Basketball is also a popular spectator sport in countries around the world. While competitive basketball is primarily an indoor sport, played on a basketball court, less regulated variations played in the outdoors have become increasingly popular among both inner city and rural groups.

Equipments

Billiard balls vary from game to game, in size, design and quantity. Carom billiards balls are larger than pool balls, and come as a set of two cue balls (one colored or marked) and an object ball (or two object balls in the case of the game four-ball). American-style pool balls, used in any pool game and found throughout the world, come in sets of two suits of object balls, seven solids and seven stripes, an 8 ball and a cue ball; the balls are racked differently for different games (some of which do not use the entire ball set). Blackball (English-style eight-ball) sets are similar, but have unmarked groups of red (or blue) and yellow balls instead of solids and stripes, and are smaller than the American-style; they are used principally in Britain, Ireland, and some Commonwealth countries, though not exclusively, since they are unsuited for playing nine-ball. Snooker balls are also smaller than American-style pool balls, and come in sets of 22 (15 reds, 6 "colours", and a cue ball). Other games also have custom ball sets, such as Russian pyramid and bumper pool. Billiard balls have been made from many different materials since the start of the game, including clay, bakelite, celluloid, crystallite, ivory, plastic, steel and wood. The dominant material from 1627 until the early 20th century was ivory. The search for a substitute for ivory use was not for environmental concerns but based on economic motivation and fear of danger for elephant hunters. It was in part spurred on by a New York billiard table manufacturer who announced a prize of $10,000 for a substitute material. The first viable substitute was celluloid, invented by John Wesley Hyatt in 1868, but the material was volatile, sometimes exploding during manufacture and was highly flammable.

Tables

There are many sizes and styles of pool and billiard tables. Generally, tables are rectangles twice as long as they are wide. Most pool tables are known as 7-, 8-, or 9-footers, referring to the length of the table's long side. Full-size snooker and English billiard tables are 12 feet (3.7 m) long on the longest side. Pool halls tend to have 9-foot (2.7 m) tables and cater to the serious pool player. Pubs will typically use 7-foot (2.1 m) tables which are often coin-operated. Formerly, 10-foot (3 m) tables were common, but such tables are now considered antique collectors items; a few, usually from the late 1800s, can be found in pool halls from time to time. Ten-foot tables remain the standard size for carom billiard games. The slates on modern carom tables are usually heated to stave off moisture and provide a consistent playing surface. The length of the pool table will typically be a function of space, with many homeowners purchasing an 8-foot (2.4 m) table as a compromise. High quality tables are mostly 4.5 by 9 ft (2.7 m). (interior dimensions), with a bed made of three pieces of thick slate to prevent warping and changes due to humidity. Smaller bar tables are most commonly made with a single piece of slate. Pocket billiards tables normally have six pockets, three on each side (four corner pockets, and two side pockets)

Chalk

Chalk is applied to the tip of the cue stick, ideally before every shot, to increase the tip's friction coefficient so that when it impacts the cue ball on a non-center hit, no miscue (unintentional slippage between the cue tip and the struck ball) occurs. Cue tip chalk is not actually the substance typically referred to as "chalk" (generally calcium carbonate, also known as calcite or carbonate of lime), but any of several proprietary compounds, with a silicate base. "Chalk" may also refer to a cone of fine, white hand chalk; like talc (talcum powder) it can be used to reduce friction between the cue and bridge hand during shooting, for a smoother stroke. Some brands of hand chalk actually are made of compressed talc. (Tip chalk is not used for this purpose because it is abrasive, hand-staining and difficult to apply.) Many players prefer a slick pool glove over hand chalk or talc because of the messiness of these powders; buildup of particles on the cloth will affect ball behavior and necessitate more-frequent cloth cleaning.