- When the piston is pulled up, the atmospheric pressure inside the cylinder will decrease.
- The atmospheric pressure outside pushes the liquid up into the syringe.
Working Mechanism of Siphon
When the sucker is pressed into place, the air inside is forced out. As a result, the pressure inside the sucker become very low. The sucker is then held in position by the high atmospheric
pressure on the outside surface.
When a person sucks through the straw, the pressure in the straw become low. The atmospheric pressure outside which is higher will force the water into the straw and consequently into the mouth.