Def: Pressure = Force

                       Area

 

Def: Pressure is force per unit area.

 

	Unit of Pressure = n/m2 or Pascal (Pa)
	The smaller the area the greater the pressure.
	The greater the depth, the greater the pressure.

	A liquid will always find the same level in connected tubes.
	The deeper you go in a liquid (Depth & Density) the greater the pressure. The denser the liquid the greater the pressure.
	Atmospheric pressure is sufficient to support a column of methylated spirits 30cm high but only 24cm of water. This is because water is more dense than methylated spirits.

 

Atmospheric pressure presses equally in all directions.

 

	Normal atmospheric pressure is sufficient to support a column of mercury 76cm high or 1,000 hectopascals.
	High pressure = Dry Weather, Low Pressure = Wet Weather

Aneroid barometer (No Liquid)

 

	Pressure in a fluid depends on depth and density.
	Pilots use altimeters to measure altitude, which is also a form of barometer