A barometer is a scientific instrument used to measure atmospheric pressure, or barometric pressure, which is the weight of air in the atmosphere. The atmosphere is made up of layers of air wrapped around Earth and has a weight. The simplest type of barometer is a tall closed tube standing upside down in a bath of mercury, which rises partly up the tube. Today, scientists and meteorologists can measure atmospheric pressure without a mercury-based barometer using a capacitive pressure sensor.
A barometer is a simple instrument for determining the pressure generated by the weight of the atmosphere and can be used for forecasting weather and determining altitude. Meteorologists often use the more precise millibar (mb), equal to exactly 100,000 Pa, to describe pressure. To read a barometer and understand its readings in terms of air pressure, it is important to maintain the air inside the vessel at the current temperature.
To protect the barometer from water, hermetically sealing the housing is possible, but this cuts off the sensor inside from the outside environment. Filling the barometer with colored water and watching the rising or falling level of the liquid in the spout can indicate weather changes.
There are readily available barometric pressure sensors that won’t require building your own rain protection. To clean the sensor, use a sharp tool to remove the adhesive, remove the top cover, and peel off the old waterproof barometric membrane. Many barometric pressure sensors have not been resistant against liquids, making it challenging to integrate them into waterproof products. Garmin recommends cleaning the sensor by running low pressure water over the port.
📹 The history of the barometer (and how it works) – Asaf Bar-Yosef
A barometer is an instrument that measures air pressure, allowing weather forecasters and scientists to better predict extreme …
📹 Isolating your BAROMETER for better Altitude …
00:00 – Start 00:13 – Betaflight & INAV Barometer Configuration 02:18 – Open Cell vs. Closed Cell Foam 03:10 – Finding the …
Thanks for this article. I have been suffering to understand this concept but none was working but now this article with the explanation of the barometer and its history with splendid animation have helped not only me but many other students to understand the complexity and art of learning science. Thank you!
As usual, nice one TED! My 3 observations in this article: 1. At 1:34 Gasparo Berti pulled his idea from his arse, literally! Thanks for the funny animation. 2. Both Aristotle and Galileo behaved like jerks with regards to their knowledge of vacuum, albeit being good in other areas. 3. How brilliant both Gasparo Berti and Evangelista Torricelli were, for thinking outside the box (or tube like you mentioned in the article!)
A vacuum exerts no force. It is the surrounding pressures that pushes the fluid into the tube to collapse the vacuum, and the weight of the fluid that establishes an equilibrium. The classic barometer is therefore a device that uses the weight(and hence pressure exerted by it) of a fluid to measure the opposing surrounding air pressure against it. As proper scientists, we always evaluate how our models would simulate the real world, and not the other way round. The world exists as it is. We merely describe it, not prescribe it. We propose models, then test them. Untested models are merely that, hypothesis, nothing more, but nevertheless, intrinsically valuable.
Worth mentioning that most times bad weather does not cause barometer drop. Small systems bring rain/snow without a drop in atmospheric pressure, actually sometimes the pressure may even increase. Mostly the large systems will cause a pressure drop. In other words., most of the time these barometers are worthless.
3:33 I don’t know if sb wondered about this or not but the reason why increasing the volume of water didn’t affect the pressure of the it and it didn’t need to go lower in the tube to be in equilibrium with the pressure outside the tube is because pressure of liquids only depends on their *density, height and gravitational field strength*. So since the two tubes are the same height, and the gravitational field strength didn’t change and we are using water in both tubes (density of fluid didn’t change) it doesn’t matter. This may seem like it doesn’t make sense but you can google to see the proof of it. And if you still don’t understand, it’s okay, if I wasn’t taking phyiscs this year I wouldn’t have understood either 😂😂😂
Aristotle was not as wrong as you think…that space above the mercury is not a vacuum (a space devoid of matter). Even mercury has a vapor pressure which means there is mercury vapor that has (partially) filled the void. Absence of matter between mercury vapor atoms yes…but THAT space above the column of liquid is NOT a vacuum.
Aristotle wasn’t wrong. The apparently “empty” bubble in a barometer is infact not a vacuum, it is filled with vapours of the liquid under it. The liquid surface under that empty gap boils away into the gap until the gap’s pressure has raised to the liquid’s vapour pressure, it’s not a vacuum. Because – just as Aristotle said – nature really does abhor a vacuum. If you got 2 barometers, each filled with different liquids of the same density but differing vapour pressures, they will give different results. Weight (more accurately density) is not the only factor.
there is actually a question about barometers that I have been wondering. Do you need to add water to a barometer over time? I have had the same barometer for many years and only filled it up when I first got it. Over time, water has dribbled out of the spout during days with very low pressure. The barometer never seems to run out of water and keeps dribbling now and then. Do I need to add more water to it now and then?
There is no vacuum in the tubes, theres is vaporized water. the water vaporizes under low pressure because of the anomaly of water. You can test this urself by putting a little bit of water into a syringe. Close the top part of and pull on the back, the water disappers into vaper and is not visible anymore. Let the backpart go and you got water again.
The mass of a 1mm square and 760 mm tall column of mercury is the same of a 10287 mm tall water column with the same section area. Is 10,28584 g the heaviest thing you can lift aplying vacuum on a 1 mm x 1 mm area. Is it correct? Since gasoline has 660 grams per liter density, vaccum could lift it 15,584 meters?
what i don’t get is, since gases and liquids are both fluids, how can the pressure act on the surface of the liquid, due to its lower density, shouldn’t air be able to flow through the liquid which is of higher density and is it not just the air being filled into the barometer tube until the density of air particles inside the column of air inside the tube matches the density of air outside the tube and thus coming into equilibrium? if that is the case it would imply that as altitude increases, the pressure increases and this causes for the volume of air inside the barometer to occupy more space and this totally makes sense when u take into account that if the temperature is highest at the surface of the earth and as we go higher in altitude the temperature decreases(due to distance from the source of heat at the surface of earth) and hence the density of air should also increase.
I mean what are you doing with the whole Aristotle thing? Aristotle was not talking about the vacuum created by sucking air out of a test tube. It was a much more meaningful vacuum… one which he did not even have the correct terminology to define because empty space was not well studied. Nevertheless, modern cosmology and physics does prove that there is no such thing is a total vacuum, and thus Aristotle’s statement that “nature abhores a vacuum” is completely sound. He was not wrong, indeed, he did not know just how right he was!
Galileo was more right and this is a sterling example of the difference between science principles and engineering. The atmosphere does NOT exert an “air pressure” nor is the effect in the tube from the weight of the air. The air molecules do have mass and are pulled ‘downward’ (toward the Earth’s center of mass) and are thus denser at lower altitudes.The air molecules are moving and, having momentum, are able to ‘share’ that momentum with things it contacts. For example, to exert a force of about 14.7 lbs per square inch of your skin…or the surface of a liquid in a barometer. Though not stated in the article, it’s important that the column be measured from the bottom of the tube to the liquid level at the top, not from either the surface of the exposed liquid or bottom of the container. It’s an old wives tale, still believed in the 21st century, that it’s the weight of the air above the barometer that’s pushing down. Not true.
vac·u·um ˈvakˌyo͞o(ə)m/Submit noun 1. a space entirely devoid of matter. Aristotle was right. Near-vacuums exist, but not vacuums. The space was not empty. It was just a very small amount of gas being stretched out to fill up space. Even in outer space, there is still a very small amount of matter. Please correct this using the description box.
I use thin “blister pack” clear plastic to fabricate hold down straps for things like U.FL antennas and such. A piece running from two of the stack mount bolts with the foam glued to that should also work. Of course the plastic would not go directly over the Baro or the foam that is on top of it. I will try it when I get an FC with a Baro on it. Yeah, I use longer stack or FC mount bolts.
It seems very strange to me that he makes that article, glues foam on the barometer and fails to actually show the sensor graph before and after. I suspect that there was not the slightest change, that’s why the article is lacking evidence. For anyone who feels uncertain: just open betaflight, enable expert mode and you’ll see the barometer data.