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 Offers 47 experiments of varied difficulty on topics ranging from buoyancy to simple machines.  Science Fair Projects About the Properties of Matter: Using Marbles, Water, Ballons, and More  Forces and Motion Science Fair Projects: Using Water Balloons, Pulleys, and Other Stuff  Science Fair Success Using Newton's Laws of Motion  Light, Sound, and Waves Science Fair Projects: Using Sunglasses, Guitars, Cds, and Other Stuff  Janice VanCleave's Magnets: Mind-boggling Experiments You Can Turn Into Science Fair Projects  Sports Science Projects: The Physics of Balls in Motion |
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A kite is a flying tethered man-made object. The necessary lift that makes the kite fly is generated when airflow over and under the kite creates low pressure above the kite and high pressure below it. In addition to the lift, this deflection generates horizontal drag along the direction of the wind. This drag is opposed with the tension of the one or more lines held by the operator of the kite. In addition to kites that are flown for recreation, art or practical use, there are sport kites and power kites. Sport kites are flown in aerial ballet. Power kites are multi-line steerable kites designed to generate excess force which can be applied in related activities such as kite surfing, kite landboarding or kite buggying.
HistoryApproximately 2800 years ago the kite was first invented and popularized in China, where materials ideal for kite building were readily available: silk fabric for sail material, fine, high-tensile-strength silk for flying line, and resilient bamboo for a strong, lightweight framework. The kite was said to be the invention of the famous 5th century BC Chinese philosophers Mozi and Lu Ban. By at least 549 AD paper kites were being flown, as it was recorded in that year a paper kite was used as a message for a rescue mission.[1] Ancient and medieval Chinese sources list other uses of kites for measuring distances, testing the wind, lifting men, signaling, and communication for military operations.[1] The earliest known Chinese kites were flat (not bowed) and often rectangular. Later, tailless kites incorporated a stabilizing bowline. Kites were decorated with mythological motifs and legendary figures; some were fitted with strings and whistles to make musical sounds while flying.[2] After its appearance in China, the kite migrated to Japan, Korea, Thailand, Myanmar (Burma), India, Arabia, and North Africa, then farther south into the Malay Peninsula, Indonesia, and the islands of Oceania as far east as Easter Island. Since kites made of leaves have been flown in Malaya and the South Seas from time immemorial, the kite could also have been invented independently in that region.[2] One ancient design, the fighter kite, became popular throughout Asia. Most variations, including the fighter kites of India, Thailand and Japan, are small, flat, roughly diamond-shaped kites made of paper, with a tapered bamboo spine and a balanced bow. Flown without tails that would hinder their agility, these highly maneuverable flat kites have a length of cutting line coated with an abrasive attached to the bridle, which is then tied to a light cotton flying line. Although the rules of kite fighting varied from country to country, the basic combat was to maneuver the swift kite in such a way as to cut the opponent's flying line.[2] Kite flying began much later in Europe than in Asia. While unambiguous drawings of kites first appeared in print in the Netherlands and England in the 17th century, pennon-type kites that evolved from military banners dating back to Roman times and earlier were flown during the Middle Ages.[2] 
During the 18th century tailless bowed kites were still unknown in Europe. Flying flat arch- or pear-shaped kites with tails had become a popular pastime, mostly among children. The first recorded scientific application of a kite took place in 1749 when Alexander Wilson of Scotland used a kite train (two or more kites flown from a common line) as a meteorologic device for measuring temperature variations at different altitudes.[2] Three years after, in June 1752, in what is the most famous of kite experiments, the American inventor and statesman Benjamin Franklin, with the aid of his son, lofted a flat kite fitted with a pointed wire and silk sail on a hemp line during a thunderstorm. Somehow both father and son avoided electrocution as a metal key attached to the flying line became electrified. Franklin proved that lightning was the natural phenomenon called electricity, not the wrath of the gods. One immediate and weird practical outcome of the experiment was Franklin's invention of the lightning rod. Materials
Kites typically consist of one or more spars to which a paper or fabric sail is attached, although some, such as foil kites, have no spars at all. Classic kites use bamboo, rattan or some other strong but flexible wood for the spars, paper or light fabrics such as silk for the sails, and are flown on string or twine. Modern kites use synthetic materials, such as ripstop nylon or more exotic fabrics for the sails, fiberglass or carbon fiber for the spars and dacron or dyneema for the kite lines. Kites can be designed with many different shapes, forms, and sizes. They can take the form of flat geometric designs, boxes and other three-dimensional forms, or modern sparless inflatable designs. Kites flown by children are often simple geometric forms (for example, the diamond). In Asia, children fly dried symmetrical leaves on sewing thread and sled-style kites made from sheets of folded writing paper. Chinese kite designs often emulate flying insects, birds, and other beasts, both real and mythical. The finest Chinese kites are made from split bamboo (usually golden bamboo), covered with silk, and hand painted. On larger kites, clever hinges and latches allow the kite to be disassembled and compactly folded for storage or transport. Cheaper mass-produced kites are often made from printed polyester rather than silk. Tails are used for some single-line kite designs to keep the kite's nose pointing into the wind. Spinners and spinsocks can be attached to the flying line for visual effect. There are rotating wind socks which spin like a turbine. On large display kites these tails, spinners and spinsocks can be 50 feet (15 m) long or more. Modern acrobatic kites use two or four lines to allow fine control of the kite's angle to the wind. Traction kites may have an additional line to de-power the kite and quick-release mechanisms to disengage flyer and kite in an emergency. Practical uses
Kites have been used for military uses in the past, both for delivery of messages and munitions, and for observation, by lifting an observer above the field of battle, and by using kite aerial photography. Kites have also been used for scientific purposes, such as Benjamin Franklin's famous (but dangerous) experiment proving that lightning is electricity. Kites were the precursors to aircraft, and were instrumental in the development of early flying craft. Alexander Graham Bell experimented with very large man-lifting kites, as did the Wright brothers and Lawrence Hargrave. Kites had an historical role in lifting scientific instruments to measure atmospheric conditions for weather forecasting. Kites can also be used for radio technical purposes, either by kites carrying antennas or by using a kite, which carries up an antenna wire ( for MF, LF or VLF-transmitters). This was done in the past, for the reception station of the first transatlantic transmission by Marconi. Captive balloons may be more convenient for such experiments, because kite carried antennas require a lot of wind, which may be not always possible with heavy equipment and a ground conductor. It must be taken into account during experiments, that a conductor carried up by a kite in the sky can lead due to a high voltage toward ground, which can endanger people and equipment, if suitable precautions (grounding through resistors or a parallel resonant-circuit tuned to transmission frequency) are not taken. Kites can also be used as light effect carrier, for example by carrying lightsticks or battery powered light effects. A German company has developed ship-pulling kites as an additional power source for cargo ships. Trials on a 55m ship have shown that, in favorable winds, the kite increases fuel-efficiency by up to 30%. This SkySails system is planned to be in commercial production by 2008. [3] Kites are also available as an auxiliary sail or emergency spinnaker for sailing boats. Self-launching Parafoil kites are attached to the mast. 
Ancient military use of kitesKites were often used in the military of China as signal equipment. Military adoption of this was more common in East Asia than in Europe. Much like modern flares, kites were flown engulfed in fire to provide a way to deliver messages to nearby or distant allies or soldiers. Kites were also used by Admiral Yi of the Joseon (1392-1910) Dynasty of Korea. During the Japanese invasions of Korea (1592-1598), Admiral Yi commanded his navy with kites. His kites had specific markings directing his fleet to perform his order. Admiral Yi was said to have over 300 such kites. The war eventually resulted in a Chinese and Korean victory, and although kites played a minor role in the war's conclusion, they were by no means a predecessor to modern day radio and/or flares. In more modern times the British navy also used kites to haul human lookouts high into the air to see over the horizon and possibly the enemy ships. The famed Cody Kite (named after the creator Samuel Franklin Cody) (see, for example, this webpage) is known for its classic beauty as well as its lifting abilities. Cultural usesKite festivals are a popular form of entertainment throughout the world. They include small local events, traditional festivals which have been held for hundreds of years and major International Festivals which bring in kite flyers from overseas to display their unique art kites and demonstrate the latest technical kites. AsiaKite flying is very popular in many Asian countries, where it often takes the form of 'kite fighting', in which kite fighters try to snag each other's kites or cut other kites down. Fighter kites are usually small, flat, flattened diamond-shaped kites made of paper and bamboo. Tails were left off of the fighter kites so that agility and maneuverability were not compromised. The usual goal of a 'kite fighter' is to maneuver his/her kite to cut the opponent's string.[4] In Afghanistan this is known as Gudiparan Bazi. Some kite fighters pass their strings through a mixture of ground glass powder and glue. The resulting strings are very abrasive and can sever the competitor's strings. The modernization of the sport of 'kite fighting' comes with newer technology, as canny arms dealers begin importing a flexible razor sharp wire from China, rather than the old, nylon fishing line used for kite string.[5] However, this practice is dangerous since the abrasive strings can also injure people. During the Taliban rule in Afghanistan, kite flying was banned, among various other recreations. In Korea kites were usually flown to make a wish or wish the person flying the kite good luck. The kites were usually flown on festive days and national holidays. In countrysides children used to take part in a fun battle where a person tried to disconnect the main bit of a kite of their opponent when the opponent tried to disconnect theirs. To disconnect an opponent's kite one would have to have a strong, steel-like thread to attach the main bit of a kite to the traditional Korean wooden reel, called Earl Leil In Vietnam, kite flown by adults are "tail-less". Instead small flutes are attached allowing the wind to "hum" a musical tune. There are other forms of sound-making kites. In Bali, large bows are attached to the front of the kites to make a deep throbbing vibration, and in Malaysia row of gourds with sound-slots are use to create a whistle as the kite flies. The Indian festival of Makar Sankranti is devoted to kite fighting in some states. This spring festival is celebrated every January 14 (or January 15 on leap years), with millions of people flying kites all over northern India. The cities of Ahmedabad and Jaipur are particularly notable for their kite fighting festivals. Highly maneuverable single-string paper and bamboo kites are flown from the rooftops while using line friction in an attempt to cut each other's kite lines, either by letting the line loose at high speed or by pulling the line in a fast and repeated manner. The activity is not without risk as the line is treated to be abrasive and flyers can, and occasionally do, fall from the rooftops. In some Indian cities kite flying/fighting is an important part of other celebrations, including Republic Day, Independence Day, Raksha Bandhan, and Janmashtami. 
In Pakistan, kite flying is a ritual for the spring festival known as Basant. However, kite flying is currently banned as some kite fliers engage in kite battles by coating their strings with glass or shards of metal, leading to injuries and death. Kite fighting is a very popular sport in Pakistan, mainly centered in Lahore people spend thousands of dollars in preparing different types of kites and threads best suited to battle. The kites that are manufactured for battling are very different from the conventional kites as they are especially designed and made for this purpose. Kup, Patang, Guda, Nakhlaoo, etc are some of the kites used in the battle and they vary in balance, weight and speed through the air. Threads for kite battling are manufactured using especial glues, chemicals and crushed glass and are numbered based on their ability to cut other threads and to handle kite's weight. Kite Battle is an art and the more experienced a person is in this art the more likely he is to win the battle. It is a very popular social event in Pakistan that happens once a year. Weifang (Shandong, China) promotes itself as the Kite Capital of the World. It is home to the largest kite museum in the world, which has a display area of 8100 m². Weifang hosts an annual International Kite Festival on the large salt flats south of the city. There are several kite museums in Japan and others in England, Malaysia, Indonesia, Taiwan, Thailand and the USA. EuropeIn Greece, flying kites is a tradition for Clean Monday, the first day of Lent. South AmericaIn Guyana, on Easter Weekend thousands turn out for mass kite flying. In the capital city of Georgetown the massive sea wall protecting the city from the Atlantic ocean is filled with throngs of families picnicking and flying kites of all shapes and colors. Many participate in kite flying competitions. In certain South American countries the verb Kitar is used to describe the art of kite-flying. Popular culture
General safety issuesThere are safety issues involved in kite-flying, more so with power kites. Kite lines can strike and tangle on electrical power lines, causing power blackouts and running the risk of electrocuting the kite flier. Wet kite lines or wire can act as a conductor for static electricity and lightning when the weather is stormy. Kites with large surface areas or powerful lift can lift the kite flier off the ground or drag them into stationary objects. In urban areas there is usually a ceiling on how high a kite can be flown, to prevent the kite and line infringing on the airspace of helicopters and light aircraft. In Asia the twine is coated with powdered glass to cut opponent's lines and these threads have been reported to have killed pedestrians or motorcyclists.[6][7] Types of kites
Types of kite lineSee also
References
External links Wikimedia Commons has media related to:
This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia Encyclopedia article "Kite" |
