KITES

Some questions about kites…

• How is it that something that is heavier than air can fly?

• How can it stay suspended in the sky with no means of propulsion?

• Why do kites of differing shapes fly? • How does size and weight affect the ability of

a kite to fly? • Do different types of kites have different flying

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History of kites

First, let’s take a look at the history of kites.

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Did you know that kites…..

• Kites originated in China about 3000 years ago?

• They were outlawed during the 18th century because they distracted shopkeepers from their duties?

• They have been used to pull boats, carriages, sleds and ice skaters?

• They have led to major scientific discoveries?

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The kite has helped to make many people famous throughout history.

Who are these people?• Benjamin Franklin

• Alexander Graham Bell• Wilbur and Orville Wright

• Leonardo da Vinci

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Benjamin Franklin

Leonardo da Vinci

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Wilbur and Orville Wright Alexander Graham Bell

Famous Discoveries with Kites

• In the 15th century, Leonardo da Vinci discovered how to use a kite to span a river– This method was later used in the construction of

one of the world’s first suspension bridges in Niagara Falls, New York

• Benjamin Franklin discovered electricity while flying a kite in 1752

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• Avid kite flyers as children, Wilber and Orville Wright developed this love into the first successful airplane. In August of 1899, they built a biplane kite. This characterized Wright’s airplane for years to come.

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Famous Discoveries with Kites

• Bell developed the first tetrahedral kite: the strongest, most rigid symmetrical structure that can exist in nature. In 1907 Bell’s kite flew for seven minutes and lofted a man 168 feet into the air.

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What is a kite?

Definition:

A kite is an unpowered, heavier-than-air flying device held to the

earth by a line.

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What are the different parts of a kite?

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Different Kite Designs

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diamond delta box

cellular Sky dancer

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dragon

stunt kite parafoil

birds fish

Materials used to build kites

• Most kite sails are: nylon, polyester, paper, or plastic.

• Most kite spars: are wood, fiberglass, plastic, or carbon.

• The best kite materials are lightweight and strong.

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Forces at Work on a Kite

• In order for the kite to fly, the upward lift force must be able to overcome the downward force of gravity.

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What creates the LIFT force?

• For a kite to use wind to offset the pull of gravity, the kite must be positioned or angled so that the wind is split over the surface of the kite into two separate streams of air.

• This air flow above the kite is faster, creating a low pressure environment whereas the air flow below the kite is slower causing the pressure to be higher resulting in "lift" which carries the kite into the air.

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Kite

Bernouilli’s Principle

Wind is made up of moving particles (atoms) which move from one direction to another.

21Bernoulli Principle Video

Lift and your Kite• The amount of lift required to cause a kite to

rise depends on the overall weight of the kite in comparison to the surface area of its sail(s).– The less amount of lift required, the easier your

kite will fly with minimal wind. – This means you should aim to create a very light

kite with a large surface area!

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Drag and your Kite• A flying kite will disrupt the continuous flow of air

around it, creating resistance against the air flow. This resistant force is known as "drag“.

• Drag reduces the lift of a kite and will cause it to fly lower on the horizon.

• A longer tail will help to stabilize your kite by adding drag below the kite without adding too much weight. The tail will help keep the kite pointed into the wind.

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How It’s MadeSeason 5, Episode 13

• http://www.youtube.com/watch?v=rbHIo7Wxt68

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