Monday 27 August 2012

A link about air pressure

http://en.wikipedia.org/wiki/Atmospheric_pressure

This article discusses the concept of air pressure, as well as atmospheric pressure.

A video on the uses of air pressure

This is how you make a game out of physics.
This particular video highlights the use of an air vortex created because of a circular exit hole for the air.

But how does the air come out in the first place?
That is air pressure.

When the air is compressed in the box (By hitting the sides), the air pressure in the box is high. This forces the air out through the hole in the box.

When the air comes out, Bernoulli's principle states that the high velocity will create a low air pressure, eventually creating the circular 'doughnut' shape because the air is moving around itself. 

Air Pressure: Introduction


AIR PRESSURE

"air pressure"

noun
the force exerted by air, whether compressed or unconfined, on any surface in contact with it.
-Dictionary

What is air pressure?
Air has weight. Air presses on every surface. Air pressure is the weight of the column of air above a horizontal surface of unit area (e.g. one square metre). The column of air extends to the top of the atmosphere. As we go up and reach a higher altitude, the pressure is lower because the column of air is reduced.

Who discovered air pressure?

Issac Newton the first European to discover the pressure measurement in units. It was later discovered by a French scientist that pressure decreases with height.

What is the significance of air pressure?

Whenever we go on an air trip, we cannot go too high on a balloon because the surrounding air pressure is too low and air is pressing inwards to create an equilibrium. 

Breathing also uses air pressure by creating a vacuum of low air pressure. By increasing the area in our lungs, we decrease the pressure, forcing air in from the surroundings.


There are disadvantages too, though.

If we go in an airplane and there is a hull breach, the normal air pressure in the plane will rush to the low air pressure of the environment. This causes everything inside the plane to rush into the hole.