Bernoulli's Principle

Bernoulli's Principle

Bernoulli's principle, physical principle formulated by Daniel Bernoulli that states that

"as the speed of a moving fluid (liquid or gas) increases, the pressure within the fluid decreases."

Experiment 1

Water flows from high pressure region to low region.

Pressure at A > Pressure at B > Pressure at C.

Experiment 2

Pressure at B becomes lowest because the speed of the water is the highest.

Experiment 3

Pressure at B becomes lowest because the speed of the water is the highest.

Bunden Burner

• When the burner is connected to a gas supply, the gas flows at high velocity through a narrow passage in the burner, creating a region of low pressure.
• The outside air, which is at atmospheric
  pressure, is drawn in and mixes with the gas.
• The mixture of gas and air enables the gas to burn completely to produce a clean, hot, and smokeless flame

Aeroplane

• When a wing in the form of an aerofoil moves in air, the flow of air over the top travels faster and creates a region of low pressure. The flow of air below the wing is slower resulting in a region of higher pressure.
• The difference between the pressures at the top and underside of the wing causes a net upward force, called lift, which helps the plane to take-off.

Insect Spray

• When the plunger is pushed in, the air flows at a high velocity through a nozzle.
• The flow of air at high velocity creates a region of low pressure above the metal tube. The higher pressure of the atmospheric air acts on the surface of the liquid insecticide causing it to rise up the metal tube.
• The insecticide leaves the top of the metal tube through the nozzle as a fine spray.