BACKGROUND:
Bernoulli is the name
of a Swiss family of famous scientists and mathematicians, from 1650's
to 1790's. Daniel Bernoulli (1700-1782) was the most famous. He was a
doctor, mathematician, professor of botany, anatomy and natural
philosophy. His most important work was Hydrodynamica dealing
with the theory of statics and motion of fluids, the subject of this
pre-lab.
The forces that lift an
airplane and hold it up, are due in part to the air that flows swiftly
over and under its wings.
Make a wing by placing one
end of the strip of paper between the pages of the book so the other end
hangs over the top of the book as shown in the diagram on the right.
Move the book swiftly through the air, or blow across the top of the
strip of paper. It flutters upward.
It doesn't matter whether
you move the air over the strip of paper by blowing or whether you move
the paper rapidly through the air, either way it rises.
Bernoulli's Principle states that an
increase in the velocity of any fluid is always accompanied by a
decrease in pressure. Air is a fluid. If you can cause the air to move
rapidly on one side of a surface, the pressure on that side of the
surface is less than that on its other side.
PROCEDURE:
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Draw the following picture on
the board.