www.TeachEngineering.org: Free Curriculum for K-12

Massachusetts Science
- 4.1 Describe and explain the manufacturing systems of custom and mass production. (Grades 6 - 8) [2001]
- 4.4 Explain basic processes in manufacturing systems, e.g., cutting, shaping, assembling, joining, finishing, quality control, and safety. (Grades 6 - 8) [2001]
- 1. Differentiate between weight and mass, recognizing that weight is the amount of gravitational pull on an object. (Grades 6 - 8) [2001]
- 6.4 Identify and explain lift, drag, friction, thrust, and gravity in a vehicle or device, e.g., cars, boats, airplanes, rockets. (Grades 6 - 8) [2001]
- 8. Recognize that gravity is a force that pulls all things on and near the earth toward the center of the earth. Gravity plays a major role in the formation of the planets, stars, and solar system and in determining their motions. (Grades 6 - 8) [2001]

Does this curriculum meet my state's standards?

Basic elements of flight
Basic manufacturing systems and processes

Do you know how a plane flies? Believe it or not, it is all because of the unique shape of the airplane's wings. Bernoulli's Principle states that as the speed of a moving fluid increases, the pressure within the fluid decreases. As the plane flies, the air traveling over and under its wing is considered a fluid. The wings of the plane are designed so that the top of the wing is curved while the bottom of the wing is flat. This creates a longer distance for the air on top of the wing to travel than the air on the bottom of the wing. Since the air on top and bottom of the wing must travel from the front of the wing to the back of the wing at the same time, the air on top of the wing must travel faster to make up for the longer distance traveled. Now applying Bernoulli's Principle, because the air on top of the wing is traveling faster, it decreases the pressure on top of the wing. Because there is a lower pressure on top of the wing and a higher pressure on bottom of the wing, it creates an unequal force on the wing causing it to lift, thus allowing the plane to fly. In this activity, students will apply this mechanism of flight to designing tetrahedral kites.

Drag:	A frictional force acting on a body (as an airplane) moving through a fluid (as air) parallel and opposite to the direction of motion.
Lift:	The component of the total aerodynamic force acting on an airplane or airfoil that is perpendicular to the relative wind and that for an airplane constitutes the upward force that opposes the pull of gravity.
Gravity:	A force of attraction between two objects due to the mass of the objects and the distance separating them.
Tension:	Two pulling forces directly opposing each other that stretch an object. Tension in the string keeps a kite from flying away.
Relative Wind:	The relative wind, therefore, is the airflow produced by the aircraft moving through the air. The relative wind is in a direction parallel with and opposite to the direction of flight.

Background

NEWTON'S 3rd LAW OF ACTION AND REACTION states that for every action there is an equal and opposite reaction.

BERNOULLI'S THEOREM states that as air passes below a wing, air also passes above it. The air on the top of the wing moves a longer distance over the curved surface of the wing, thus it moves faster reducing the pressure above the wing. The air below the wing moves more slowly causing the air pressure below the wing to be larger than the pressure above the wing. It is the change in relative pressures above and below the kite that allows the kite to lift.

Kites were the first flying devices ever made by humans. The word "kite" gets its name from a bird in the hawk family known for its grace in the air. Kites come in a wide variety of shapes and sizes and have been used for many purposes throughout history, although today, kite flying is done largely for recreation. See Figure 1 for a full picture of a tetrahedral kite.

Figure 1: Example of tetrahedral kite.
click for copyright

Recommended Resources:

http://easyweb.easynet.co.uk/~s.stapleton/kites/build.html

http://www.asahi-net.or.jp/~et3m-tkkw/history-table.html

http://www.geocities.com/Colosseum/4569/history.htm

http://www.zianet.com/katgraham/kites/eddylesson.html

http://www.intellicast.com/KITEcast/Windandkites/

http://www.skratch-pad.com/kites/fly.html

http://wings.avkids.com/Curriculums/Vehicles/kite_summary.html

Preparation

Obtain Materials
Photocopy Worksheets

With Students

Phase One: Making Pyramids

Obtain six straws, measure and cut a 72" (182.88cm) long piece of kite string. Thread 4 straws on the kite string. Hold on to the ends. Keep approximately 3" (7.62) of string towards end A.
Arrange the straws onto a diamond shape and use the pipe cleaner "needle" to feed the string through the starter straw, so that it comes out between straw 1 and straw 2.
Add the fifth straw and place it across the center of the diamond.
Feed the "needle" back through the third straw so that it comes out between straw 2 and 3.
Add the sixth straw. Pull up the straws so that a triangle is formed. Tie it off so that your triangles form a stable pyramid shape. Now, using steps 1-5 make 9 more pyramids!

Phase Two: Building the Kite

Pictures of each step can be seen at http://ford.berea.k12.oh.us/Kitewebpage/Tetra.htm (Ref. 1).

Using the template, carefully trace and cut out 20 tissue paper shapes.
Cover two sides of each pyramid with tissue paper. Fold the edges of the tissue paper around the straw and glue in place.
Assemble the kite. Begin with the bottom layer. Arrange three pyramids side by side so that they only touch by one corner and the front of each is a covered panel (all of the covered panels should lie in a plane). The other covered panel should be lying flat on the table. Knot the pyramids at the points where they meet. Arrange two pyramids behind those three so that the front covered panels of the two new pyramids faces the same direction as the front three. The back corners of the front three just meet the front corners of the two behind. Knot the two pyramids at all points that touch. Attach one more pyramid to the back corners of the row with two, again facing the covered panel forward. Be sure that all knots are secure!
Add the second layer of pyramids. Arrange two pyramids side by side (make sure the covered panels are on the bottom and front). Knot them to each other. Align the bottom corners of these two with the peaks of the front five pyramids on the bottom layer. Knot these two pyramids to the bottom layer. Arrange and attach a third triangle behind the two you just attached. Be sure that all knots are secure!
Add the third and final layer. Attach a single pyramid on top of the second level still having the covered panel facing forward. The finished kite itself looks like a giant pyramid. Be sure that all knots are secure!
Attach kite strings to the corners where the front panel meets the back panel. With the strings here, the panels will face downward when in flight and the triangles will look like birds in flight.
Add a tail to keep the kite properly oriented towards the wind.

Phase Three: Flying your Kite

Check the knotting. Attach flying string. Go out and fly your kite!

How and why do objects move upward?
Why do kites fly?
How can a team of students most efficiently produce a finished product - the tetrahedral kite - using manufacturing processes?
How will modifications of the project's initial design alter the kite's performance?