Measurement Tools

# Barometer: Types, Work And Definition With Photos

We will explain that what are types of barometer in detail with definition and the work of barometer. In addition: we will express that what is atmospheric pressure? types of barometer

## What is a barometer? types of barometer

A barometer is a measuring instrument used to evaluate atmospheric pressure. In other words, it detects the pressure exerted by the atmosphere on a certain point. Its unit of measurement is the hectopascal (hPa), the unit hecto means one hundred. Being invented by the physicist and mathematician named Torricelli, it is also known as the Torricelli tube.

The mercury barometer often determines the unit of measurement, which is called “inches of mercury” or “millimeters of mercury” (mmHg). A pressure of 1 mmHg is 1 torr (by Torricelli). types of barometer

## What is atmospheric pressure?

It is the force exerted by the air on any point in the atmosphere. That is, when the air is very cold, it descends and the pressure increases, and if, on the contrary, the air is very hot, it rises, and the pressure decreases.

## How does a barometer work?

There are different types of barometers, because each type varies its construction and manufacture, each one has a different principle of operation.  types of barometer

## Types of barometers types of barometer

There are mainly 2 types according to the operating principle of mercury and aneroid, although within each type of barometer we can find some variations, such as in mercury we can find Torricelli and Fortín, in the aneroid we find altimeters and barographs .

### Mercury types of barometer

Torricelli tube

The first barometer was built in an 850mm long glass tube which contains a liquid (usually mercury), it is also made up of a larger container filled with the same fluid as the tube. Its operation is based on the displacement of the mercury inside the tube, which as the atmospheric pressure increases, the weight of the air exerts more pressure on the container which causes it to push the liquid higher inside the tube. When the pressure drops, the air becomes lighter, and less force is exerted on the container causing a drop inside the glass tube.types of barometer

Normal pressure equals 760 mm inside the Torricelli tube, atmospheric pressure can also be measured in atmospheres (atm); 1 atmosphere, was defined as the mean atmospheric pressure at sea level.types of barometer

1 atm = 760 mmHg = 101.325 Pa = 1013.25 hPa

Fortín Barometer

Basically it is the modification of a Torricelli tube, since being the first barometer it had the disadvantage of not being transportable due to the danger of air entering the tube or, even worse, because the shocks of the mercury with its upper part could break it. easily. These drawbacks were overcome with the Fortín barometer.types of barometer

### Aneroid types of barometer

This instrument does not use mercury, and is also called a holosteric or metallic barometer. It works through a metal capsule in which a vacuum has been generated. Said capsule has elastic elements (flexible diaphragm) which undergo deformations due to changes in atmospheric pressure. These variations are those that modify the position of a needle that travels a circular scale graduated in millimeters of pressure. It adjusts according to the indications of a mercury barometer.

Barometric altimeters

This type is used mainly in aviation with the peculiarity that its scale is converted into meters or feet of altitude. Indicates the difference in altitude between the point where it is located and a reference point; it is usually used to know the height above sea level.types of barometer

Barograph

This instrument is dedicated to continuously recording changes in atmospheric pressure. To take the reading, an android barometer is incorporated.