Activity: Make a Kite

Jasmin with the kite

On SCOPE's Flight episode, you saw Jasmin make a kite. Here's how she did it. Watch the clip.

What you need

• Paper
• Crayons
• String (for the bridle)
• Bamboo
• Ribbon
• Tape
• Fishing line (for flying line)

What to do

1. The paper needs to be a diamond shape, with the bottom triangle being twice the size of the other.
2. Now is the best time to decorate the kite.
3. After decoration, turn the kite over and tape the bamboo sticks in place. They will form a cross when taped onto the kite's length and width. Make sure you tape the longest stick first.
4. Fold you ribbon in half and tape the middle of it to the tail of the kite.
5. Next take about 15cm of string and tie a loop. This is then attached to the middle of the bamboo cross and poked through a hole to the non-bamboo side of the kite. This is the bridle.
6. Lastly, attach the flying line to the bridle.
7. Go fly a kite!

What's happening?

Humans have been flying kites for a very long time. The ancient Chinese were great kite builders. Legend has it that lightning was discovered to be electrical during a science experiment by Benjamin Franklin with a kite - not one to try at home though.

The science behind flying a kite is fairly straightforward, and is actually quite similar to aeroplane flight. Kites are flown so that they angle into the wind, and as air hits the kite it is deflected downwards. If air is being deflected downwards then according to Newton 's laws where every action has an equal and opposite reaction, the kite is pushed upwards.

Another way to think about it is that the air travelling under the kite is slowed down by hitting in the kite, whereas the wind that travels over the top is not slowed down. This results in air travelling faster over the kite than under it. The effects of this is that the kite is pushed upwards, just like an aeroplane wing, because the faster moving air has less pressure than the slower moving air, and the kite moves from higher pressure to lower pressure (up!).

This theory of faster fluids creating lower pressure is called the Bernoulli principle. Try blowing between two inflated balloons to see what happens as fast moving air moves between the two balloons, creating an area of lower pressure.