Question

What is meant by atmospheric pressure? Mention three examples to illustrate its effect.

Answer 1

1. The pressure exerted by the Earth's atmosphere is called atmospheric pressure.
2. It is the normal force exerted per unit area of Earth's surface by the column of air above that surface.

Its effect can be illustrated in the following examples.

1. Drinking straw - When we suck the air inside a straw dipped in any liquid, the air present outside (in the atmosphere) pushes the liquid inside the straw, and eventually, inside our mouth.
2. Fountain pen - When we fill ink in a fountain pen, we squeeze the tube of the pen. This leads to the air inside the tube being pushed outside. This causes a low pressure inside the tube and the atmospheric pressure pushes the ink inside the tube.
3. Syringe - When we fill any liquid inside the syringe, we pull its plunger outwards. This creates a low pressure inside the syringe tube and the atmospheric pressure pushes the liquid inside the syringe.