The pressure of an object is how much force it is exerting over an area. For example, if an elephant has a mass of 1000kg, and occupies an area of 10m2, then using the formula:

  $ pressure = \frac{force}{area} $

The pressure exerted by the elephant = 10000N/10m2 = 1000N/m2 or 1000Pa (Pascals)

This shows why it hurts more if someone stands on you with stilettos, it hurts more than if the same person (i.e. the same force) stood on you with normal shoes - the pressure is greater for the former, as stilettos take up a smaller area.

Pressure due to LiquidsEdit

$ pressure=density \times gravity \times height $


Pressure in GasesEdit

Pressure can be measured in gases with a N-tube partially filled with a coloured liquid. Atmospheric pressure pushes down on one side, and the gas of whose pressure you want to measure pushes down on the other side. The difference in hight between the two levels of the liquid tells you the difference in pressure.

You can also measure atmospheric pressure with a barometer.