What is a Barometer?
A barometer is a device used for measuring atmospheric pressure through air, water, or mercury. You must have heard forecasters giving measurements in millibars (MB) or mercury. The changes in air pressure are measured with barometers for predicting short-term changes happening in the weather. As air pressure is monitored by weather forecasters, falling barometer measurements signal upcoming bad weather.
Usually, when a low-pressure system is about to happen, you must be prepared for rains and storms with warmer weather. When a high-pressure system is about to come, you can expect cooler temperatures and clear skies.
The Invention of a Barometer
You must be wondering whose idea it was to come up with a device that measures air pressure. Well, the answer is Evangelista Torricelli. The barometer’s invention is credited to Torricelli, an Italian physicist and mathematician who studied under Galileo. Torricelli started to use his vacuum theory for gauging air pressure as well as making predictions through them.
Even though he was behind the barometer’s invention, the name was coined by the Englishman Robert Boyle somewhere in the mid-1600s. He came up with the term by combining two words which means “measuring weight” in Greek.
Types of Barometers
Barometers usually come in three different kinds. Aneroid barometers are used in meteorology for measuring pressure without the use of any liquid. Mercury barometers are also used, which come with vertical glass tubes immersed in vessels brimming with mercury. When there is a rise in atmospheric pressure, mercury also spikes up.
These days, there are cutting-edge digital alternatives that anyone can use- from amateur learners to the more experienced and professional meteorologists. You will be surprised to know that even your phones can be used as barometers. Today’s contemporary smartphones now come with pressure sensors built inside their bodies for picking up changes in the weather. They can also calculate the current altitude of the user.
How does it Exactly Work?
You already know by now that a barometer uses pressure for predicting the weather. It uses atmospheric or barometric pressure for this. The gravity of the Earth’s surface pulls towards itself the weight of the layers of air present in our Earth’s atmosphere. A barometer would pick up on the differing pressure. As the air motion in our atmosphere determines the weather, the barometer would enable the user to monitor the changes while predicting how the weather will be over shorter time periods.
Talking about Air Pressure
We can feel the atmospheric pressure all around us, all the time, no matter where we go. Atmospheric pressure, or air pressure, is a constant force exerted on us by the weight of small particles of air. These small air particles, known as air particles, are not visible to the naked eye. But they are present all around us. They carry weight and hence are always “pushing” down on us. Give this a try- look right up in the air and imagine a long column of air right above your head. It goes all the way up towards the edge of the atmosphere of our planet.
The weight of this column of air is actually the quantity of air pressure exerted on us. When we climb a mountain or go up a higher elevation, the air pressure lowers down. The length of the air column above us gets reduced by the amount of increase in our elevation.
Let’s Talk about Air Molecules
While moving higher up the elevation, you may also experience a ‘pop’ in your ears. It is for balancing the pressure between the outside and inside the ear. ‘pop’ can be uncomfortable for some people. That is why a lot of people stuff their ears with cotton while getting into a flight. As the number of air molecules reduces while moving higher, you may also probably require to breathe faster for breathing in more molecules. It is to make up for the molecular deficit. These molecules also occupy space.
As there is a vast space among the air molecules, the air is either filled in a vast area or is compressed for fitting into a smaller space. It is said that air goes under high pressure when it is compressed. When there is a change in air pressure, it signals low-pressure or high-pressure regions of the air.
These areas are known as fronts. When air molecules are in high-pressure regions, they tend to flow to the low-pressure regions. This flow of air is what we called molecules wind. The strength of the winds is determined by the amount of difference in pressure in areas. The bigger the difference, the stronger will be the winds.
Why Don’t we Feel the Pressure?
The Earth’s atmosphere is continuously pressing down on us with a force of around 15 pounds every square inch. Are you wondering why don’t we feel the air’s heaviness or why doesn’t this extreme pressure crushes us down completely? It is all because we breathe. The air in our bodies balances out that pressure we get from the air present in the atmosphere. It saves us from getting squished by whatever pressure the atmosphere puts on us. We cannot sense the constant air pressure force as the air inside us balances the pressure outside. Moreover, we are all accustomed to that feeling. (See What are the diameters of Domino’s large, medium, and regular-sized pizzas?)
The Popularity of Barometers
When the device was first invented, it was seen as a desirable instrument and was often flaunted as a status symbol. It is said that many rich and scientifically minded people use barometers to adorn their homes and show off their high status in society. It took nearly two and a half-decade for the barometers to get marketed in the private society.
Once the device hit the commercial market, various artisans, including furniture makers and clockmakers, started creating impressive pieces to withhold the barometers and transform them into decorative items for homes. Over the following centuries, these devices gained the status of prized possessions and were solely found in the nobles’ houses.