Plunger

A plunger is a tool that is used to release stoppages in plumbing. It consists of a rubber cup with an attached stick (shaft), usually made of wood or plastic. A different bellows-like design also exists, usually constructed of plastic.

Use

For the common plunger, the cup is pushed down against the drain opening, either pressing hard into the drain to force air in, or pushing down until the rubber cup is flattened and then pulling out, creating a vacuum that attracts material. The intent is to loosen or break up a blockage caused by excessive material in the drain.

Shape and function

The cup of a kitchen plunger looks like a rubber ball cut in half with a flared edge, while the toilet plunger's cup looks more like a distorted ball, tapered on one half, with a large hole on the bottom.

A plunger is much more effective with water in the pipe because water does not compress and will thus transmit more of the applied force than air. When a plunger is ineffective, it is supplemented by a chemical drain cleaner (in the case of sinks and tubs) or a plumber's snake (for stubborn clogs or clogs of the main line or toilet).

Plunger (experimental submarine)

Plunger (also called Holland V) was an experimental submarine which was evaluated by the United States Navy from 1898 to 1900. It is not to be confused with USS Plunger which was commissioned by and served in the U.S. Navy.

History

Plunger was the fifth submarine designed and built by Irish engineer and inventor John Philip Holland. It was a 149-ton experimental steam-powered submarine had its design approved in October 1893 and built under a U.S. Navy contract issued in March 1895.

Plunger features, most of them novel for the time, included three propellers, a steam engine plant, a retractable smokestack, thrusters to facilitate maneuvering, a camera lucida (an optical device serving as a periscope) and two torpedo tubes. She was, possibly, the first submarine designed to fire self-propelled torpedoes.

Plunger was constructed at the Columbia Iron Works in Baltimore, Maryland and launched in August 7, 1897. The Navy conducted dock trials with Plunger in 1898. Her complex steam power plant proved impractical for a submarine and the boat was not accepted for service by the Navy. In July 1899 reconstructing Plunger with new engines was considered, but it was decided against.

Pinball

Pinball is a type of arcade game, usually coin-operated, in which points are scored by a player manipulating one or more steel balls on a play field inside a glass-covered cabinet called a pinball machine. The primary objective of the game is to score as many points as possible. Points are earned when the ball strikes different targets on the play field. A drain is situated at the bottom of the play field, partially protected by player-controlled plastic bats called flippers. A game ends after all the balls fall into the drain. Secondary objectives are to maximize the time spent playing (by earning "extra balls" and keeping the ball in play as long as possible) and to earn bonus games (known as "replays").

History

Pre-modern: Development of outdoor and tabletop ball games

The origins of pinball are intertwined with the history of many other games. Games played outdoors by rolling balls or stones on a grass course, such as bocce or bowls, eventually evolved into various local ground billiards games played by hitting the balls with sticks and propelling them at targets, often around obstacles. Croquet, golf and paille-maille eventually derived from ground billiards variants.