Do you feel the pressure??

In your Sec 1 chapter on pressure, you learnt how to calculate the pressure exerted by an object using the formula: Pressure = (Force) divided by (Contact Area). Similarly, the air around us (atmosphere) also exerted pressure on our bodies. The atmosphere is the layer of air enveloping the earth. It extends up to 1,000 km above the surface has a total weight of 4.5 x 1018 kg. This weight exerts a pressure on the surface of the earth called atmospheric pressure. But why don't we feel the atmospheric pressure? It is because within our body there is also similar pressure exerted out. You experience popping sensations in your ears when you are travelling in a lift to a very tall floor. Your body is equalizing the difference in pressure in environment. Aircraft cabins need to be pressurized at sea level when flying at high altitude for our comfort. At high altitudes like at top of mountain where air pressure is lower, there is pressure difference between body and atmospheric pressure. Breathing becomes difficult and nose bleeding may occur.

How can you demonstrate the effect of atmospheric pressure? Simply place a few sheets of newspaper are placed over a wooden ruler on the edge of a desk. A sharp blow breaks the ruler in half. Do get your science teacher to help you in this simple demonstration. It will be really cool if you can do this in your group presentation.


Brain-Teaser: You are in a space craft and falls into space (vacuum) accidentally? Will you survive out there?