BAROMETER

 

Definition:

Barometer is a device, which is used to measure atmospheric pressure.

MERCURY BAROMETER

CONSTRUCTION:

Mercury barometer consists of one-meter long glass tube closed at one end and a mercury bath.

WORKING:

Fill the tube with the mercury, Covet the open end with thumb firmly and invert the tube in a vessel containing mercury. Remove the thumb some of the mercury will fall in the vessel. The length of the mercury column in the tube is referred to as the atmospheric pressure, which is 760 mm.