Question

What is an aneroid barometer?
Draw a neat and labeled diagram to explain its construction and working.

Answer 1

Aneroid barometer is a portable type of barometer.

In this, no liquid is used. It consists of a metal box corrugated to make it flexible. The lower side of the box is fixed to the base of the instrument and the upper side is supported by a stout spring S. The box is partially evacuated. So it tends to collapse under the pressure of air. The stout spring balances the thrust on the metal box due to normal air pressure and prevents the box from collapsing.
When atmospheric pressure changes, the surface supported by the spring S moves in if pressure increases or out if the pressure decreases slightly. This small movement is increased considerably by a system of levers one end of which is connected to the spring S. The other end of the lever system is connected to a chain which is wrapped round a spindle carrying a pointer. The pointer moves over a scale which is graduated to read the pressure in centimeters or inches.