The purpose of this experiment was to determine what shape produces
the least amount of aerodynamic drag.
I became interested in this idea when I was reading a book on blimps
and I wondered what shape produces the least amount of drag.
The information gained from this experiment will help anyone who needs
aerodynamic information such as people working in Boeing who are designing
jet liners and hobbiests who need some basic aerodynamic information.
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My hypothesis was that the "teardrop" design would produce the least
I base my hypothesis on information from World Book Encyclopedia that
says that a teardrop shape will produce the least drag.
The constants in this study were:
the wind tunnel used
setting of vacuum cleaner
material shapes are made of
surface area of shapes
source of dry ice
room wind tunnel is in
type of spring scale used
size of spring scale used
fullness of bag in vacuum cleaner
type of glass used on all sides
type of wood used on all sides of wind tunnel
method of making shapes
tools that helped me make the shapes
device use to hold the shapes
type of attachment used to fasten shapes to spring scale.
The manipulated variable was the shape used.
The responding variable was the amount of drag produced.
To measure the responding variable I used a spring scale connected to
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||small vacuum cleaner
||30x60 cm plywood panel
||20x30 cm plywood panel
||30x40 cm plywood panel
||12.5x30 cm plywood panels
||12.5x30 cm strip of styrofoam
||hand drill with .62 cm bit
||heavy duty black trash bag
||roll of black cloth tape or duct tape
||bottle of epoxy glue
||device for poking small straw-sized holes
||can of flat black paint
||double sided cone, teardrop, cube, and sphere, all with same frontal
||can of yellow paint
1. Stand the two strips of plywood edgewise on a flat surface, separated
by 30 cm.
2. Lay the largest panel across the strips so that the edges match
3. Nail them together.
4. Punch holes in the styrofoam 1.25 cm apart.
5. Punch a hole between the two center holes.
6. Put the straws into the holes in the styrofoam.
7. Cut off the straws where they protrude.
8. Lay the 20x30 cm panel across the left side of the structure so
it fits neatly over the vent to create a box.
9. Nail the panel into place.
10. Paint the panels black.
11. Lay the piece of plexiglass on the top of the tunnel so that it
fills up the remaining space.
12. Paint the styrofoam shapes yellow so that no small holes are to
13. Allow the paint to dry.
14. Hang the spring scale above the wind tunnel.
15. Take out the styrofoam vent piece.
16. Attach the shape you are going to use to the spring scale using
17. Make sure the wind tunnel is air tight.
18. Do necessary adjustments.
19. Hook up vacuum cleaner to the bottom of the wind tunnel, making
sure no air can get out.
20. Measure the weight of the shape you are going to use.
21. Turn the vacuum cleaner on.
22. Measure the spring scale.
23. Subtract the first measurement from the second.
24. Repeat steps 14-23 twice, with different shapes.
25. Record data.
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The original purpose of this experiment was to determine which of these
shapes produced the least drag: double-sided cone, teardrop, cube, and
The results of the experiment were that the teardrop produced the least
drag, 1 gram, the double-sided cone was second, with 1.5 grams, the sphere
was third, with 3 grams, and the cube was fourth with 6.5 grams.
See the table and graph below.
My hypothesis was supported.
The results indicate that this hypothesis should be accepted.
Because of the results of this experiment, I wonder if the surface texture
made a difference
If I were to conduct this project again I would vary surface texture.
table and graph
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The people I would like to thank for help on my project are: Mr. Ken Newkirk,
Mrs. Rita Pasckvale, my father, Mr. Jeffrey J., and my mother, Mrs. Holly
Aerodynamics is an interesting subject. It is the study of how
air and water affect objects moving through them. The four basic
principles of aerodynamics are lift, drag, thrust, and weight.
Lift is the force that keeps aircraft in the air. It is dependant
on thrust to give it enough energy. The standard aircraft wing is
rounded at the front and on the top, flat on the bottom and with a leading
edge at the back. Air flowing over the top goes faster than the air
flowing under the wing and so creates a zone of lower pressure. The
low pressure zone creates more lift the more rounded the wing is and the
faster the wing is traveling, but creates more drag.
Thrust is the force acting to propel the airplane forward. Thrust
is usually created using a gasoline engine driving a propeller or a jet
engine. The more thrust there is, the more lift there is.
Drag is the force that slows the aircraft down. Drag is created
when molecules of air collide with the molecules of the hull. This
is a type of friction. The denser the atmosphere and the faster the
aircraft is going, the more drag there is.
Gravity pulls an airplane toward the earth. Weight is the total
pull of the earth on each of the molecules of the aircraft. The lower
the altitude and the more massive the plane, the more weight there is.
For an airplane to fly, its weight must be counteracted by an equal amount
Aerodynamic efficiency has to do with how much drag is created by speed.
By rounding corners and polishing surfaces, aircraft can become much more
efficient. Also, there are different tricks to make aircraft much
more efficient, but they are mostly known only by the professionals.
One trick is to have a rounded shape in the front, tapering to a point
in the back. This leads the air smoothly into the airstream.
Without this technique, swirling air pockets form in the air behind the
shape, slowing the shape down.
Aerodynamics is, therefore, a complicated and interesting subject.
It not only covers aircraft but also cars and any other method of transportation,
especially boats, the only difference being lift does not apply to ground
and sea-based methods.
"Aerodynamics", World Book Encyclopedia, 2000.
"Beginners Guide to Aerodynamics", avalible on http:\\www.nasa.gov
downloaded on November 2, 2000
"Aerodynamics", Encarta 2001
Jim Mc Cabe, "An Introduction to Aerodynamics", availible at http://www.nas.nasa.gov/services/education/resources/tutorials/jmccabe/aerodynamics-introduction.html
"Aerodynamic Drag Force", Robert Vigars, availible at http://www.instruct.uwo.ca/kinesology/241a/ppoints/ss20/
"Aerodynamics: Drag", Encarta 2001
Mr. Newkirk is the best science teacher (in my opinion) in the state
of Washington. He gave me huge amounts of help and encouragement
regarding my science project. Also, I hope he will give me a better
science grade for writing this paragraph, even though he said, smiling,
that he would not. Mrs. Pasckvale is Mr. Newkirk’s aide in the classroom.
She was of great aid in helping me get the materials in my project and
helping me to remake my board and journal after it got trashed at the Regional
My father and mother also gave great support. My father helped
me construct the wind tunnel and do the experiment, and he gave me invaluable
help on doing my procedures and the rest of my journal. My mother
helped me with the aesthetics of my project. She helped me to revise
my display board, among other things.
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