EXTREME SPORTS

extreme sports

Bungee jumping, also spelt bungy jumping, is an activity that involves a person jumping from a great height while connected to a large elastic cord. The launching pad is usually erected on a tall structure such as a building or crane, a bridge across a deep ravine, or on a natural geographic feature such as a cliff. It is also possible to jump from a type of aircraft that has the ability to hover above the ground, such as a hot-air-balloon or helicopter. The thrill comes from the free-falling and the rebound.When the person jumps, the cord stretches and the jumper flies upwards again as the cord recoils, and continues to oscillate up and down until all the kinetic energy is dissipated.

Bungee jumping

Land diving is a rite of passage for boys of the South Pacific island of Pentecost The land diving of Pentecost Island in Vanuatu is an ancient ritual in which young men jump from tall wooden platforms with vines tied to their ankles as a test of their courage and passage into manhood. Unlike in modern bungee-jumping, land-divers intentionally hit the ground, but the vines absorb sufficient force to make the impact non-lethal.The land-diving ritual on Pentecost has been claimed as an inspiration by AJ Hackett, prompting calls from the islanders' representatives for compensation for what they view as the unauthorised appropriation of their cultural property.A tower 4,000 feet (1,200 m) high with a system to drop a "car" suspended by a cable of "best rubber" was proposed for the Chicago World Fair, 1892–1893. The car, seating two hundred people, would be shoved from a platform on the tower and then bounce to a stop. The designer engineer suggested that for safety the ground below "be covered with eight feet of feather bedding". The proposal was declined by the Fair's organizers.

History

Early tethered jumping

Etymology

The word "bungee" originates from West Country dialect of the English language, meaning "Anything thick and squat", as defined by James Jennings in his book "Observations of Some of the Dialects in The West of England" published 1825. In 1928, the word started to be used for a rubber eraser.[6] The Oxford English Dictionary records early use of the phrase in 1938 relating to launching of gliders using an elasticated cord, and also as "A long nylon-cased rubber band used for securing luggage"."Bungy" is the usual spelling in New Zealand and other countries.

Modern sport The first modern bungee jumps were made on 1 April 1979 from the 250-foot (76 m) Clifton Suspension Bridge in Bristol, England, by David Kirke, and Simon Keeling, members of the Oxford University Dangerous Sports Club, and Geoff Tabin, a professional climber who tied the ropes for the jump.The students had come up with the idea after discussing a "vine jumping" ritual carried out by certain residents of Vanuatu.The jumpers were arrested shortly after, but continued with jumps in the US from the Golden Gate Bridge and the Royal Gorge Bridge (this last jump sponsored by and televised on the American programme That's Incredible), spreading the concept worldwide. By 1982, they were jumping from mobile cranes and hot air balloons. Colorado climbers Mike Munger and Charlie Fowler apparently pre-dated the above event in Eldorado Springs, CO in 1977. Both were cutting-edge alpinists, and they were trying to prepare mentally for a trip to Monte Fitzroy in Patagonia by simulating long falls onto a springy, 150-foot nylon climbing rope. They scrambled up to a large tree at the top of the 700-foot wall, above a severely overhanging climb (already appropriately named "Diving Board") and tied one end of the rope into the tree. Using a piece of flat, seat belt webbing around his waist and some homemade leg loops, Mike tied into the other end of the rope and, after no small amount of trepidation, he jumped. He then ascended the rope mechanically to the tree and untied. Then Charlie tied in and jumped. Total fall was about 130 feet. Jump from Nevis Highwire Platform in New Zealand Organised commercial bungee jumping began with the New Zealander, A J Hackett, who made his first jump from Auckland's Greenhithe Bridge in 1986.During the following years, Hackett performed a number of jumps from bridges and other structures (including the Eiffel Tower), building public interest in the sport, and opening the world's first permanent commercial bungee site, the Kawarau Bridge Bungy at the Kawarau Gorge Suspension Bridge near Queenstown in the South Island of New Zealand.Hackett remains one of the largest commercial operators, with concerns in several countries.

Several million successful jumps have taken place since 1980. This safety record is attributable to bungee operators rigorously conforming to standards and guidelines governing jumps, such as double checking calculations and fittings for every jump. As with any sport, injuries can still occur (see below), and there have been fatalities. A relatively common mistake in fatality cases is to use a cord that is too long. The cord should be substantially shorter than the height of the jumping platform to allow it room to stretch. When the cord becomes taut and then is stretched, the tension in the cord progressively increases. Initially the tension is less than the jumper's weight and the jumper continues to accelerate downwards. At some point, the tension equals the jumper's weight and the acceleration is temporarily zero. With further stretching, the jumper has an increasing upward acceleration and at some point has zero vertical velocity before recoiling upward. See also Potential energy for a discussion of the spring constant and the force required to distort bungee cords and other spring-like objects. The Bloukrans River Bridge was the first bridge to be used as a bungee jump launch spot in Africa when Face Adrenalin introduced bungee jumping to the African continent in 1990. Bloukrans Bridge Bungy has been operated commercially by Face Adrenalin since 1997, and is the highest commercial bridge bungy in the world. In April 2008, a 37-year-old Durban man, Carl Mosca Dionisio, made bungee jumping history when he jumped off a 30 m (100 ft) tower attached to a bungee cord made entirely of 18,500 condoms.

Equipment

The elastic rope first used in bungee jumping, and still used by many commercial operators, is factory-produced braided shock cord. This special bungee cord consists of many latex strands enclosed in a tough outer cover. The outer cover may be applied when the latex is pre-stressed, so that the cord's resistance to extension is already significant at the cord's natural length. This gives a harder, sharper bounce. The braided cover also provides significant durability benefits. Other operators, including A. J. Hackett and most southern-hemisphere operators, use unbraided cords with exposed latex strands. These give a softer, longer bounce and can be home-produced. Accidents where participants became detached led many commercial operators to use a body harness, if only as a backup for an ankle attachment. Body harnesses generally derive from climbing equipment rather than parachute equipment.

I think bungee jumping is a very exciting exterem sport.

Prepared by:M.Kürşat YÜCE

Source:Wikipedia