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Air pressure pushes in all directions but slow-moving air
pushes harder than fast-moving air.
Airplane Wing Shape
This experiment is a
demonstration of Bernoulli’s
Principle. Swiss mathematician
Daniel Bernoulli (1700-1782)
showed that faster-moving air
exerts less pressure than
slower-moving air. When you
blow between the two balls,
you lower the air pressure
between the balls. So the
higher air pressure surrounding
the rest of the balls pushes
them together.
Air Pressure and Flight
Put a sheet of paper just below your mouth and blow
hard over the top of it as in the illustration. If you do
this, the air pressure under the paper is greater than that
above it, so the paper rises up. That’s how planes fly.
slower
-moving air—high pr
essure
faster-moving air—low pressure
lift due to pressure
difference