How Does A Barometer Work?

There are two types of barometers and both of these models work in different ways.
A mercury barometer has a glass tube that contains mercury and that sits upside down on a container called a reservoir. This barometer works by the level of the mercury in the glass being balanced with the amount of pressure in the atmosphere. It is designed to act just like a set of scales, so if the mercury weight is less than the atmospheric pressure, the level of the mercury in the glass will rise.
The pressure of the atmosphere is the weight of the air and this helps experts and weather enthusiasts predict certain weather conditions. As such, the level of mercury will either move up or down the glass tube depending on the air pressure around it.
These days, a digital barometer is usually used by weather stations, although mercury versions are usually the most readily available to the everyday weather enthusiast.
A digital barometer works by using electrical charges to measure the air pressure. This helps weather stations to predict changes in the weather in a more accurate and timely fashion. For example, if the atmospheric pressure is slowly rising on the digital barometer scale this will predict more settled weather. On the other hand, if the pressure suddenly drops and continues to drop over a period of a few hours, this will usually predict an impending storm.

The barometer works by balancing the weight of mercury in the glass tube against the atmospheric pressure just like a set of scales. If the weight of mercury is less than the atmospheric pressure, the mercury level in the glass tube rises. If the weight of mercury is more than the atmospheric pressure, the mercury level falls.

A barometer is used to predict the weather. It works by regsitering atmospheric pressure. Generally speaking, a fall in atmoshpere will result in bad weather and a rise will indicate good weather.
There are two types of barometer, a mercury barometer and an aeroid barometer.
The mercury barometer works on the principle that a column of mercury will rise and fall with the changes in atmospheric conditions. When the atmospheric pressure falls the weight of the mercury causes the column to fall and vice versa when the atmosphere rises.
The aneroid barometer is not widely available and is oftent hought to be less reliable. This works by a pointer which is attached to a vacuum filler pair of metal bellows. The bellows expand or contract under atmospheric pressure which causes the pointer to move to indicate either rising pressure or a fall in pressure.
Baromters should always be fixed to a wall which backs onto the outside of a house. This gives more accurate readings than if fixed onto an internal wall.

A mercury barometer measures atmospheric pressure, when the atmospheric pressure falls the weight of the mercury causes the column to fall and vice versa when the atmosphere rises.

It measures atmospheric pressure, which is by balancing the mercury's weight inside the clear glass tube against the weight of the air in the atmosphere.