Barometer vs Manometer – Find the difference?


We employ a variety of equipment to measure pressure. Manometers and barometers are devices that measure pressure, although their uses and events differ. For instance, it’s possible that their operating concept is similar. This article will explain what a barometer and a manometer are, as well as how they differ from one another. In this post, we also go into their calculations, work, and applications.

What is a barometer?

The air pressure above or below sea level can be measured using a barometer. Weather patterns created by high and low pressure along with the barometer aid in weather forecasting. Evangelista Torricelli, an Italian physicist, created the first barometer in 1643. He places mercury in a vacuum, examines its attributes, and creates the barometer for the first time in history.


The weight of the mercury displayed on a glass tube’s scale determines how well a barometer functions. The barometer’s mercury level drops, which is visible on the scale, when the mercury weight exceeds the atmospheric pressure. When the weight of the mercury is less than the air pressure, the barometer’s mercury level rises, allowing it to more accurately anticipate the atmospheric pressure. By observing the changes in mercury levels, you may determine the air pressure. When mercury levels rise, the mean atmospheric pressure rises as well, or the other way around.

Types of barometer:

There are two major types of barometers, which are given below:

Mercury barometer:

A mercury-filled Torricelli tube serves as the basis of the mercury barometer. As atmospheric pressure rises, greater pressure is exerted on the tube, raising the mercury’s level as shown by the scale. The liquid level drops as the atmospheric pressure drops, and you may compute the pressure from this by measuring how much air pressure is lost on the tube.

Aneroid  barometer:

A brand-new, sophisticated, and digital barometer is the aneroid barometer. It is made up of an aneroid capsule with a metal box constructed of copper and beryllium alloy. This metal box is firmly sealed due to atmospheric pressure because we want the levers and springs to expand and compress more effectively. Additionally, this barometer displays the atmospheric pressure on a digital scale.

What is a manometer?

A piece of equipment called a manometer is used to gauge pipeline pressure. Manometers have been used to measure pressures other than atmospheric pressure. any kind of pressure, including that in steam, liquid, gas, etc. Because of its high density, mercury makes up the majority of the liquid in the U-shaped tube of this instrument, which has both ends accessible to the air.


As you are aware, the manometer’s tube is open on both ends; one end is connected to a source pressure via a gas-tight seal, and the other is left open to atmospheric pressure. As you are aware, the test pressure is always one atmosphere (atm) above atmospheric pressure, and the liquid level in the tube rises as the pressure increases.

Differences between manometer and barometer

Physical characteristics:

A manometer is a U-shaped, open-ended tube that is filled with mercury or water and is free from air pressure that presses from both sides. It can measure various gaseous pressures. The mercury level typically moves along the testing pressure with one end linked to any high-pressure, bulb, or gas sealed and the other end open for ambient pressure.

Liquid inside:

A heavy liquid with a high density is needed in a barometer, depending on its size, thus mercury can fulfill all the instrument’s requirements and clearly display variations in air pressure. No liquid has been required for use in digital or aneroid barometers; just air cells have.

Most manometers employ heavy liquids, but open-ended manometers use lighter liquids like water, oil, benzene, and bromides to prevent poisoning and toxicity that can occasionally cause by mercury.

Pressure calculation: 

Height disparities in manometers can be calculated in hectopascals using measurements in millimeters or inches. Which arm of the tube contains more liquid is measured when the manometer’s one end is opened and one high-pressure gas is connected to it. When there is more liquid on the open-end arm, the gas exerts more pressure, which is added to by air pressure. When there is more liquid on the opposite arm, the gas exerts less pressure, and you can measure the pressure of the test gas.


A meteorologist uses a barometer to anticipate the weather, and it has been utilized for weather forecasting. By measuring air pressure, barometers are able to forecast changes in weather patterns.

With the exception of air pressure, a manometer can measure all types of pressure. The blood pressure instrument that doctors use to gauge our body’s BP level is a popular form of manometer and is referred to as a sphygmomanometer.


Both the barometer and the manometer have been used to measure pressure, although the barometer can measure atmospheric pressure, which aids in weather forecasting, while the manometer can measure pressures other than atmospheric pressure for liquid, gas, and steam.

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