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What is a barometer and what it is used for?

Last Updated: 06.12.23


A barometer is a scientific instrument that is used in meteorology to measure the atmospheric pressure. The atmospheric pressure, also known as barometric pressure, is the pressure within the atmosphere of Earth. The pressure varies smoothly and since it changes with the weather, a barometer is a great instrument for home use and can help gauge these minuscule changes.

The pressure tendency can also help scientists or any person that has done his or her homework to forecast short-term changes in the weather. There are also numerous measurements of air pressure that are used in surface weather analysis to help find surface troughs, frontal boundaries, and high-pressure systems.

You shouldn’t mix the pressure altimeter with the barometers. They might be essentially the same instrument, but they are used for entirely different purposes. An altimeter is designed to be transported from place to place matching the atmospheric pressure to the corresponding altitude.

A barometer, on the other hand, is kept stationary and this allows it to measure the more subtle pressure changes caused by weather. An exception to this rule is when it comes to ships at sea. A ship can use a barometer because its elevation does not change.

For this exact reason, you are likely to find many fishermen that rely on the barometer to keep them safe and to catch more fish. On a fishing ship where the weather can change at any second, such an instrument will help keep the fishers prepared for any subtle change just like an autoclave will provide safety for a lab’s personnel, no matter what samples may enter it, so have a peek here for more insight.

There are many types of barometers available for purchase. The oldest design comes from the concept postulated by Lucien Vidie who used a water-based instrument to predict the changes in weather. The design is rather simple, it consists of a glass container with a sealed body half filled with water.

There is a narrow spout that is open to the atmosphere. When the air pressure is lower than at the time the body was sealed, the level of the water inside the spout will rise above the water level in the body. When the air pressure increases, the water level in the spout will instead drop.

This is the best explanation of how a barometer works and a variation of this type can be easily made at home by anyone who has the time. Of course, for more precise measurements and more complex instruments and techniques are required.

The most common type of barometer nowadays is the aneroid barometer, while the mercury variant ceased to be manufactured due to how hazardous the material could be to human health. The mercury alternative consists of a glass column that is marked off in inches, very similar to how a quality thermometer would look like.

The aneroid barometer, on the other hand, is made without fluid. It consists of a small and flexible metal box called an aneroid capsule. The capsule is made from an alloy of beryllium and copper. The metal box is sealed tightly so that any changes in barometric pressure in the environment will cause an expansion and contraction of levers and springs inside the unit.

While both options work great and use the same basic principles of expansion and contraction, they do it in completely different ways. Although accurate, when compared to aneroid barometers, the mercury variant is relatively simple. Because it utilizes a complex mechanism, the aneroid option can register minute changes in atmospheric pressure.

The use of barometers in modern society has only grown in the last years. What was once a hefty device that required a lot of space, has now been miniaturized enough not to be larger than your favorite infrared thermometer, and sometimes even smaller than that.

Such instruments have been used in weather forecasting since the late 19th century. They are best when used in combination with wind observations as that is when they can give the most accurate short-term forecasts.

You don’t have to be a scientist to use a barometer. They are a great purchase for fishers that want to be sure that no storm will surprise them while they’re on the ocean. Aneroid barometers are also used in scuba diving to help keep track of the contents of the diver’s air tank.

What’s more, you might be surprised to find out that you might already have a barometer near you. Indeed, some phone manufacturers have equipped their flagship smartphones with a built-in and highly precise barometer.


Ioana Moldovan

Ioana’s professional experience in the optics field has helped her understand the value of passing her knowledge forward. Her curious personality helps her gather useful information for her readers and her goal is to make technical information fun and accessible to everyone.

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