What makes a barometer work

Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products.

List of Partners vendors. Share Flipboard Email. By Jenny Worboys. Featured Video. Cite this Article Format. Worboys, Jenny. Winds and the Pressure Gradient Force. How to "Speak" Weather Forecasting. Your Privacy Rights. To change or withdraw your consent choices for ThoughtCo. At any time, you can update your settings through the "EU Privacy" link at the bottom of any page.

Since he was careful not to let any air into the tube, there was a vacuum in the space that developed above the mercury column. Indeed, this was the first time anyone in a laboratory had ever created a vacuum and a vacuum made that way is called a Torricellian vacuum in honor of its inventor.

Around sea level, the atmosphere will force down a pool of mercury and make it rise in a tube to about mm about 30in in height. A fluidless aneroid barometer is developed. It consists of a small, flexible metal box called an aneroid capsule, made from a beryllium and copper alloy. The metal box is tightly sealed so that changes in atmospheric pressure outside of the box allow the levers and springs inside the box to expand and contract.

The barometers were mainly used to measure patterns of weather. When used in combination with wind observations, barometers can provide considerably accurate weather forecasts for the short term. They are also used to measure an aircraft's speed by checking the air moving pressure against the aircraft. They also serve as indicators of altimeter settings for providing aircraft altimeter altitude information.

This post examines what exactly a barometer is, the different types of barometers, and detail how each one works. Barometers have evolved through the centuries and come in all shapes and sizes. It is also used in more industries than just the weather and climate sectors. However, it still predominantly remains a meteorological instrument.

You might be wondering why a barometer is such a vital part of any weather measuring device. You can see a detailed explanation of how atmospheric pressure influences the weather in this article. Since no evidence of an actual experiment could be found, Evangelista Torricelli is widely acknowledged as the inventor of the barometer in Torricelli was the first scientist who concluded that the air in the atmosphere had weight and exerted pressure on objects below it.

This argument was not supported and believed by most of his peers, including Galileo. Torricelli continued to work in secret due to the politics and beliefs of the time.

He realized he needed a liquid heavier than water to conduct his experiment. As a result, he successfully used mercury and became known as the inventor of the mercury thermometer. Blaise Pascal became aware of Torricelli's design, and over time, went on to test and perfect Torricelli's design. As stated in the introduction, a barometer is a meteorological instrument that measures the atmospheric pressure of air in the environment. Before looking at how they work, the different types of barometers first need to be identified.

Since each barometer functions in a different way, it will then be possible to look at each one separately and describe how it works. Barometers can be divided into four main types. Each one will be briefly described, and in the next section, we will look at how each one works. Invented by Evangelista Torricelli in , as discussed in the previous section, the mercury barometer is one of the earliest barometers ever designed. It uses an open flat pan and a sealed vertical glass tube filled with mercury to measure changes in air temperature.

The water barometer we are familiar with today is better known as a weather ball barometer. This simple device consists of a sealed glass container with a long narrow open spout connected to it. It is partially filled with water. The aneroid barometer was invented in by Lucien Vidi, a French physicist. In space, there is a nearly complete vacuum so the air pressure is zero.

On Earth, because there are many miles of air molecules stacked up and exerting pressure due to the force of gravity , the pressure is about Why might that be? If you've read How Hot Air Balloons Work , you know that hot air is less dense lighter than cooler air. And that would be true. These same sort of pressure differences occur all over the planet for various reasons. These pressure differences have a big effect on the weather, so if you know the current air pressure at your house, as well as the pressure trend, you are able to predict certain things about the weather.

As a very loose rule, a high-pressure area will be clear, and a low-pressure area will be cloudy and rainy. Sign up for our Newsletter!