Why barometer uses mercury

This is because 1 atmospheric pressure causes mercury to rise to mm up in the tube. The mercury barometer was invented by Evangelista Torricelli. He was a physicist and mathematician. Torricelli was born in Faenza, Italy on October 15, He died on October 22, , in Florence, Italy.

Evangelista moved to Florence, Italy to assist Galileo. In the vacuum experiments of Evangelista, Galileo suggested he use mercury. He filled a four-feet long glass tube with mercury. He then inverted it into an empty dish. A part of the mercury from the tube escaped but some of it remained. He observed the creation of a vacuum in the tube. Torricelli was the first scientist to create a sustained vacuum and discover the principle of a barometer. He studied and realized that the day-to-day height variation of mercury was caused due to the changes in the atmospheric pressure.

The atmospheric pressure at any level in the atmosphere depends on the weight of the air present overhead. A mercury barometer can be referred to as a device or a scale that measures the weight of the atmosphere above the location. With the understanding of the principle of a See-Saw, figuring out the functioning and principle of a mercury barometer is simple. A mercury barometer serves as a balance.

The weight of mercury present in the device balances the weight of the atmosphere at a given place. The atmospheric pressure cannot be measured on a balancing scale due to the presence of air on both scales. Therefore, a Mercury Barometer works on the principle of balancing the atmospheric pressure with the volume of mercury present in the device. However, there are traditional kinds of mercury barometers as well.

We have discussed the working of a traditional mercury barometer below. Also known as a Torricellian barometer, it consists of a container filled with mercury and a glass tube that has one end sealed. The open end of the long and hollow vertical glass tube is positioned at the bottom of the mercury container.

At sea level, with the increase in the air temperature, the mercury in the glass tube rises because the increase in temperature pushes down on the mercury inside the container.

With the decrease in the air temperature, the mercury in the tube drops down due to the decrease in the pressure. The working of the mercury barometer is affected by the increase in altitude. At a higher altitude, the pressure falls with the increase in altitude. The atmosphere at higher altitudes does not push down on the mercury in the container which does not result in the rising of mercury so far in the tube.

The positioned glass tube has measurements or markings on its side. The atmospheric pressure is recorded by reading it through the measurements on the tube. Whether it is a barometer or a thermometer, mercury is used. This is because the use of mercury is more convenient than using water.

In effect, water is less dense and less heavy than mercury. Due to this, the air pressure lifts a certain volume of water much higher up the tube than the same volume of mercury.

You might need a tall tube to use water in your barometer which will make it so enormous to be impractical. A mercury barometer is primarily designed to be used for measuring atmospheric temperature. However, there are various other uses of a mercury barometer. Reading a mercury barometer is not an easy task but not too complex. It requires the correct height to be measured after the content is balanced in the glass tube.

Mercury has high density and low length is essential for pressure measuring. Its high density helps to make small manometers. It does not evaporate like water would, and its lower freezing point means it will not freeze up at 0 deg C. Simply it has compactness, visibility and stability. In barometer mercury is preferred over water because mercury has high density and low vapour pressure.

Atmospheric Pressure is the force per unit area exerted on a surface due to the weight of air molecules above it.

It is caused by the collisions of the air molecules with that surface. We measure atmospheric pressure with a barometer- the height of a column of a mercury indicates the pressure exerted by the air. Asked by: Umbelina Arrobo asked in category: General Last Updated: 7th May, Why is the fluid in a barometer mercury rather than water or another liquid?

Mercury is commonly used in barometers because its high density means the height of the column can be a reasonable size to measure atmospheric pressure. A barometer using water , for instance, would need to be What is a barometric liquid? Barometric Liquid Defined A barometer is an instrument used to measure atmospheric pressure and the liquid inside it used to measure the atmospheric pressure is barometric liquid.

Barometer uses Mercury A highly Poisonous liquid metal as it's liquid. What will happen if water is used in place of mercury in a barometer tube? That is, if water is used in barometer tube instead of mercury, the length of the tube must be greater than A greater height will be difficult to hold in a vertical position and needs a high tower to install the barometer.

So, we cannot replace mercury by water in the barometer. What are the factors that affect the atmospheric pressure at a place? Factors Affecting Air Pressure: Temperature: As the temperature increases, air expands because of which its density decreases which results in low pressure.

Which liquid is used in aneroid barometer? How do we measure atmospheric pressure? A barometer is a scientific instrument used in meteorology to measure atmospheric pressure.

A simple barometer consists of a long glass tube closed at one end, open at the other filled with mercury and turned upside down into a container of mercury. Why mercury is used in sphygmomanometer?