Experiments with the
venturi tube revealed that air passing through the tube behaves the same way as
water. When the air passes through the tubeís throat (narrow section) it moves faster.
When the air moved faster the pressure decreased. That means the greater the
speed of the air the les pressure exerted.
Suppose air is
moving through a venturi tube that has a small hole in its throat. Tiny bits of
paper scattered near the hole will be pushed into the tube because the outside
air pressure is greater than the pressure in the throat. The greater the
airflow in the throat, the greater the inward will be. This principle is used
paint sprayers and car carburetors to move liquid using pressure differences.
In an airplane the air moving above the plane is moving faster than the air
below. This means that there is a pressure difference as shown by Bernoulliís
If itís still
difficult to understand, consider your garden hose. Without a nozzle the water
flows at a certain rate. With a nozzle the flow of water speeds up.
Another example of
how it works is using a bottle of paint and making it into spray paint. There
is drop in air pressure around the paint therefore causing it to rise.
Meanwhile air is being pushed out of a syringe-like plunger. The air causes the
paint to become spray like. This is the venturi effect.
Which way do you want to go?