Since Bernoulli's Principle tells us that faster moving air results in
a decrease in air pressure, we can see how air can be caused to push
unevenly on objects around us. Airplanes, by lowering the pressure over
the wing, are able to get pushed into the air by the higher air
pressure underneath the wings. This is explained more fully in . The following experiment help to demonstrate how lift is
created by the application of Bernoulli's Principle:
Materials:
• 1/2 a sheet of
typing paper (cut lengthwise)
• ruler
• tape
Procedure:
This experiment involves making a simple "wing" to help us
understand how a wing's shape allows it to apply Bernoulli's Principle
and thus gain lift. Begin by folding the piece of paper in half
widthwise. Next, tape the top edge of the paper so that it is about
1/2" from the bottom edge; this will make the top half of the paper
curved like the top of a wing. This is your model wing. Slide the wing
over the ruler so that the curved side is facing up and the folded seam
is facing you. Holding the ruler in front of you with the wing hanging
down, blow straight at the folded seam. The wing will lift up from its
hanging, at rest position.
Think about the
following:
• By having a
curve over the top of the wing, what happens to the distance that the
air over the top of the wing has to cover--compared with the distance
the air has to travel under the wing?
• How
is the velocity of the air going over the top compared to the velocity
of the air going under the wing? What is the effect of the air pressure
over the top of the wing/under the wing? Why is the wing lifted then?
• Explain
your rationale of why the wing will be lifted to the person sitting
next to you.
