Applications of Atmospheric Pressure

1. Drinking Straw

• air pressure inside becomes lower when air is sucked from a drinking straw.
• the higher atmospheric pressure acting on the surface of the drink pushes the drink into the drinking straw and enables it to be sucked into the mouth.

2. Syringe

• consists of a tight-fitting piston which moves in a cylinder with a nozzle at one end.
• commonly used to injecting medicine into the body and for watering plants
• the pressure is reduced when the nozzle is dipped into a liquid and the piston is pulled up.
• the higher atmospheric pressure acting on the surface of the liquid pushes the liquid into the cylinder.
• when the piston is pushed down again, the liquid is ejected.

3. Rubber Sucker

• it is a rubber cup that can be made to stick on to a smooth wall such as glass or tiled wall.
• made air-tight by wetting its rim before pressing it against the wall to create a partial vacuum by driving the air out.
• higher atmospheric pressure acting on the outer surface of the cup presses it in position against the wall.

4. Vacuum Cleaner

                             

• it applies atmospheric pressure to remove dust particles.
• when it is switched on, a fan sucks out a stream of air to create a partial vacuum ( space X )
• higher atmospheric pressure outside pushes the air and dust particles into the space X.
• dust particles are trapped in the dust bag while the fat moving air is allowed to flow out from the back of the vacuum cleaner.

5. Siphon

Siphon Principle

• the difference in air pressure produces a continuous flow through the rubber tube as long as the point is located lower than the liquid level in the tank.