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Stability Science: How Tails Help a Kite Fly

更新时间:2012-08-28    来源/发布:www.en369.cn    作者/编辑:英语作文网

Key concepts
Aerodynamics
Wind
Flight
Forces

Introduction
Have you ever tried to build your own kite? Kites have been a source of entertainment through the centuries for kids worldwide. And they've been used for scientific experiments, too—Benjamin Franklin flew one to investigate lightning. (Something you shouldn't do!) In this activity you will have a chance to build your very own kite—a simple sled kite—and use it to investigate how tails help kites fly. After trying out this activity you may add tails to other kites to help them soar to greater heights!

Background
Did you know that, besides Ben Franklin, one of the most famous kite flyers of all time was a 10-year-old boy? His name was Homan Walsh, and without him the Niagara Falls Suspension Bridge may not have been built in 1847. Before construction could begin, someone needed to get a line across the Niagara River Gorge. Homan successfully flew a kite from one side of the gorge to the other over the treacherous rapids below and, after securing his kite string, heavier line was fed across until a steel cable could connect both shores and bridge construction could begin. Homan was rewarded with a $10 cash prize, which was a lot of money in 1847!

How does a kite fly? As someone runs with a kite, the wind going head-on into the kite causes a lift force on it. This force is perpendicular to the wind, pushing the kite up. At the same time, the force of drag pulls the kite back, in the direction that the wind is going.

There are many different kite designs. Some are very old, like traditional Chinese and Japanese kites. Some designs are very new, like the dynamic stunt kites used in sport-kite flying competitions. Their modern materials and designs make them ultra-maneuverable.

Materials
• Printer
• Paper
• Scissors
• Crayons and markers (optional)
• Tape
• Two drinking straws
• Hole punch
• Kite string
• Measuring tape or ruler
• Paper clip
• Plastic grocery bag or other thin plastic bag
• An open, clear area outside

Preparation
• Download the Sled Kite Template (pdf) and print it out on a sheet of eight-and-a-half-inch by 11-inch paper.
• Carefully cut out the sled kite. You can decorate it using crayons, markers or other media.
• Trim the length of the two drinking straws so they will fit in the area marked for the straws. Tape the straws in place.
• Place three pieces of tape in the marked areas covering the black circles to reinforce the holes for the kite string. Using a hole punch, carefully punch the two holes marked by the black circles.
• Cut two pieces of kite string to make each 45 centimeters (cm) long. Tie a string through each hole. Tie them tight, but not so much that you tear the paper. Tie the opposite end of both strings together to one end of a paper clip.

本文标签

Science

Kite

Tails

Help

fly

A

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