How Low Can It Go? Design a Kite that Flies Best in Low Winds

Building Three Types of Kites

1. Build three different kinds of kites to compare. For example, you could compare a box kite, a diamond kite, and a sled kite. Visit this NASA website for pictures of different kinds of kites.
   1. The size and surface area of the kites should be roughly equal.
   2. A wide variety of kite kits and kite accessories are available at department, hobby, and toy stores. You can even design and build your own kites from scratch.
2. Completely assemble each kite.
3. Attach 1 meter (m) of flying line to each kite.

Setting Up the Test Area

1. Place the fan in a room that has at least 3 m of open space in front of the fan so you can fly the kites. If you don't have that amount of space at home, get permission to use your school gym or another large room at school. The area should be free of drafts.
2. Point the fan in the horizontal direction that you will use for the experiments.
3. The center of the fan should be 1 m above the ground.
   1. If you are not able to adjust the height to 1 m, simply use the available height and modify the procedure accordingly.
4. Starting at the fan, lay down a 3-m line of masking tape on the floor, perpendicular to the front of the fan.
5. Mark the masking tape every 0.5 m, using the washable marker.

Measuring the Wind Speed

1. Turn the fan on its lowest setting.
2. Use the anemometer to measure the wind speed at different distances form the fan.
   1. Use meters per second (m/s) as the units for wind speed.
   2. Measure the wind speed at the 0.5-m marks on the masking tape.
   3. Use the meterstick to ensure that the anemometer is at the same height for each reading.
   4. Use the framing square to ensure that the meterstick is at a right angle to the floor.
3. Make a data table that shows the distance, in meters, and the corresponding wind speed.
4. Graph the distances from the fan on the x-axis and the wind speeds on the y-axis.
5. Repeat steps 1–4 of this section for the fan's middle and top speed.

Testing the Kites

1. Place the meterstick perpendicular to the floor, 3 m away from the fan.
   1. The meterstick should be upright, in relation to the floor.
   2. Have your helper hold the meterstick upright.
2. Tape the flying line from the first kite to the top of the meterstick.
   1. Start with 1 m of flying line, but feel free to adjust to a length of string that works best for you.
3. Have another helper hold the kite out toward the fan, so that the flying line is horizontal to the ground, and the kite is facing the fan.
4. Turn the fan on its lowest setting.
5. Let go of the kite.
6. Record whether the kite flies (the string is horizontal or higher) or whether it falls back down. Record in which distance each kite started to fly.
   1. Add a column to the data table, showing distance from the fan and wind speed.
7. Repeat steps 2–6, but this time, at the position 0.5 m closer to the fan.
8. Record whether the kite flies (the string is horizontal or higher) or whether it falls back down.
9. Repeat steps 2–6, getting progressively closer to the fan, in 0.5-m increments, until the kite flies.
10. Record the distance at which the kite first flies. You can identify the wind speed at this distance, based on your previous measurements.
11. Repeat steps 2–10 with the fan set at the medium and high speeds.
12. Repeat steps 2–11 with the other two kites.
13. On the graphs for wind speed vs. distance, add an arrow showing at what distance each kite started to fly.
14. Record your observations about which style of kite is best for flying at low wind speeds.
15. Once you have worked through the whole procedure with each kite, repeat Measuring the Wind Speed and Testing the Kites at least two more times so that you have three trials. This ensures that your results are accurate and repeatable.