Applications of Bernoulli’s Theorem

Bernoulli’s theorem finds many applications. Some commonly observed phenomena can also be explained on the basis of Bernoulli’s theorem.

Flow meter or Venturimeter

It is a device used to measure the rate of flow of liquids through pipes. It consists of a manometer, whose two limbs are connected to a tube having two different cross-sectional areas.

Spray gun

When the piston is moved in, it blows the air out of the narrow hole with large velocity creating a region of low pressure in its neighborhood. The liquid (e.g. insecticide) is sucked through the narrow tube attached to the vessel end having its opening just below narrow hole. The liquid on reaching the end gets sprayed by out blown air from the piston.

Bunsen Burner

When the gas emerges out of the nozzle, its velocity being high the pressure becomes low in its vicinity. The air is rushed in through the side hole and gets mixed with the gas. The mixture then burns at the mouth when ignited, to give a hot blue flame.


The carburetor is a device used in motor cars for supplying a proper mixture of air and petrol vapours to the cylinder of the engine. The energy is supplied by the explosion of this mixture inside the cylinders of the engine. Petrol is contained in the float chamber.