Bernoulli's principle describes the relationship between pressure acting at a spot on a liquid's surface and particle velocity.
According to this principle, the total energy of a small amount of incompressible liquid traveling through a stream from one point to another remains constant during the displacement.
The action of paint gun
We all know that a spray gun is a type of atomizer or a device that sprays liquids.
The figure shows a rubber bulb (represented by 'B'), a narrow glass tube (represented by 'T'), and a narrow aperture at the end (represented by 'O') in a spray cannon mechanism.
The tube is put into the liquid, as can be seen. When we squeeze the rubber bulb, air rushes through the tube and out the tiny aperture at the other end.
Because the 'O' aperture is narrow, the velocity of the air as it departs will increase.
As a result, the pressure near 'O' decreases and there is a pressure difference.
The liquid in the bottle rises through the vertical tube due to the pressure differential. However, the liquid is blown into a fine spray by the stream of air that comes through the tube as the bulb is squeezed.
As a result, we may claim that a paint gun's action is based on Bernoulli's principle.
Hence, the paint gun's action is based on Bernoulli's principle.