Come Fly With Me

Karlene Kurth Walther Lutheran High School
900 Chicago Ave.
Melrose Park, IL 60160


For intermediate grades through high school

1. Students will state Bernoulli's principle which is "the pressure in a moving
stream of fluid is less than the surrounding fluid."

2. Students will observe examples of Bernoulli's principle.

3. Students will apply what they have learned about guiding airplanes by
designing and constructing a model glider whose direction of flight can be

Materials needed:

For Demonstration: notebook paper, shoebox, text book, medium sized ball,
straws, water, beaker, vacuum cleaner with exhaust valve, ping-pong ball

For Activity: shoebox, styrofoam, thread, rubber bands, unsharpened pencils,
straws, fan


Through opening demonstrations students should be able to formulate a
relationship between moving air streams and the effect they have on objects in
the path of the stream. The following demonstrations will be utilized:
1. Place two textbooks with a sheet of notebook paper on top on the table
top. Ask a student volunteer to attempt to blow the sheet of paper off
the books by blowing under the paper. (The paper should be forced down.)
2. All students hold their textbooks vertically and place a sheet of
notebook paper in the book so that the paper hangs over the edge away
from them. Students attempt to force the paper down by blowing across
the top of the paper. (The paper should be pushed up.)
3. A student volunteer blows through a funnel which has a ping-pong ball in
it. He/she attempts to blow the ping-pong ball out of the funnel.
Attempt to blow when the funnel is right side up and also when it is
inverted. (The ball should stay in the funnel regardless of the
direction the funnel is held.)
4. Place medium sized ball on the nozzle of the vacuum cleaner exhaust.
Turn the vacuum cleaner on. (The ball should levitate at some height
above the vacuum cleaner in the air stream.)
5. Blow through a half straw across the top of another half straw that is
placed in a beaker of water. (A spray of water should come out of the

After these demonstrations the instructor will lead a discussion of the
events observed. Stress where the high pressure regions and where the low
pressure regions are. Diagram this on the board, label the highs and lows. It
should be apparent that the low pressure areas are where there is a moving
stream of air. State Bernoulli's principle. Relate the principle to air
Introduce the activity of controlling direction of flight. Define terms
ailerons, elevators, rudders. (Ailerons are flaps that can be raised or lowered
on the wings, elevators are flaps on the tail, and rudders are on the tail.)

1. Wings and tails are made of styrofoam meat packages. Wings have dimensions
of 20 cm x 5 cm. Ailerons should be rectangles on the back edge of the wing
and evenly spaced from the center of the wing. Sides of the ailerons should
be cut and the front edge should be folded. Tails are 15 cm x 4 cm with
elevators made the same way as ailerons but they will tend to be a bit
smaller. About 3 cm from each end of the tail fold the tail up and place a 2
cm slit though the folded part to form rudders. These should be folded to
the left and right.

2. Attach the wing and tail to the pencil with rubber bands.

3. Adjust the wing and tail so that the plane balances when holding by a thread
attached to the front and rear of pencil.

4. Hold plane in front of wind tunnel. The wind tunnel is made of a shoebox
that has sections inside made of poster board and the back cut out. Inside
the sections are rows of half straws. This provides a steady even stream of
air flow when placed in front of a low speed fan.

5. Test each control by bending the ailerons, elevators, and rudders in all

Conclude activity with a group discussion of concepts. Results of the tests
should show that ailerons cause one wing to dip to the right or left, elevators
cause the plane to nosedive or rise up, and rudders control left or right turns.
Relate these movements to air flow and high and low pressure.

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