Building kites and flying kites is an informal pastime as well as a competitive sport in many parts of the world.
In Korea, men, women and children fly kites during the first few days of the New Year.
Kites' flying is an important part of the boys' festival held each May in Japan, and in China, one day each year is celebrated as Kites' Day.
On those days, thousands of kites shaped like fish, butterflies and dragons float over the cities and towns.
There are also kite-flying competitions held yearly in the United States and Canada.
Types of Kites There are many different types of kites.
The simplest kind of kites is the two-stick single plane bow kite.
It can be purchased ready-made or it can be assembled from do-it-yourself kits or made completely by hand.
For simple kites the sticks can be of any strong lightwood with a straight grain.
The covering material can be ordinary brown wrapping paper, or a lightweight clothe, such as silk or nylon.
Plastic sheering of various kinds is also used.
In addition, cloth is used for the tail and a string for the flight line.
There are more advanced types of kites that can be made.
The box kite consists basically of two rectangular boxes, open on two parallel sides each and connected by a common framework.
Lawrence Hargrave invented it in the 1890's.
Box kites are more difficult to build than stick kites, but they are excellent flyers and will maintain their position for long periods.
Box kites also adjust well to changes in the wind, and they do not require a tail.
How to fly kites Kites fly, like airplanes, on the aerodynamic principle of wind pressure against a heavier-than-air object.
The motor and propeller of the airplane create a wind pressure as they move the plan through the air.
When the pressure is great enough to overcome gravity, the plan is pushed up and allowed to remain aloft.
The same effect of wind pressure is created by the kite flyer as he runs across an open field.
As the kite moves against the wind, the string tips the face of the kite forward.
The wind pushes up on this tipped face and lifts the kite, just as a wedge pushed under an object lifts it up.