What are the applications of atmospheric pressure?

Atmospheric pressure enables suction, lifts liquids in straws and pumps, operates barometers and syringes, and helps vacuum cleaners and suction cups work.

Air exerts about 101.3 kPa at sea level. Devices exploit pressure differences: when you lower pressure in a container or tube, higher outside air pressure pushes on fluids or surfaces to produce motion or grip.

Common applications

• Drinking through a straw: You reduce mouth pressure; outside air pushes the drink up.
• Syringes and pipettes: Pulling the plunger lowers internal pressure; atmospheric pressure drives liquid in.
• Vacuum cleaners: Fans lower pressure in the intake; higher room pressure forces dusty air into the nozzle and bag/filter.
• Barometers: Atmospheric pressure balances a mercury column height or deflects an aneroid cell, indicating weather changes.
• Lift pumps: Limited by atmospheric pressure; on Earth, suction can raise water to ~10.3 m at best.
• Suction cups: Pressing expels air; outside pressure holds the cup to the surface.
• Packaging and sealing: Vacuum packing lowers inside pressure; atmospheric pressure keeps seals tight.
• Lungs ventilation assist: During inhalation, thoracic expansion drops alveolar pressure slightly below atmospheric; air flows in.