Where there is increased flow in a fluid or air, you will find decreased pressure. As the air passes over the central part of the tube more energy is used up as the molecules accelerate. This leaves less energy to exert pressure, and the pressure thus decreases. Demonstration of the Bernoulli Effect Two empty soft drink cans are placed on several drinking straws.
Air pressure forces the cans to roll toward each other.
Shower curtain sucked in when shower turned on. As a wing passes through the air its shape makes the air travel more quickly over the top of the wing than beneath it. This creates a higher pressure area beneath the wing than above it. The pressure difference cause the wing to push upwards and lift is created. The faster the wing moves through the air the more air is forced over and under the wing, therefore the more lift is created.