It is fair to say that physics is a specialized field requiring a good amount of background knowledge and understanding to fully comprehend. That being said, I do think there are some topics that are valuable for everyone to at least get a vague handle on. One such is the way that we go about measuring vacuum pressure.
Now, I know that the first image that this phrase likely elicits for you is of a vacuum cleaner. While this concept can be applied to them, that is not the main focus of this article. Rather, I will be discussing the formula and how to apply it in a practical sense. If you are ever uncertain about a word or phrase, look at a resource like this one, https://www.britannica.com/science/vacuum-physics, for more details.
What is Vacuum Pressure?
I think the best place to start with this is by explaining what a vacuum is in the first place. There are a few ways that we can define it. There is no matter in a space considered a vacuum, and generally speaking, the pressure is so low that if there are particles of matter, they don’t actually impact the space.
We measure it in a unit called pascal. As far as creating a vacuum, there are several methods. One such is to empty the desired location of all air using a specialized pump. The other is to use a swift injection of fluid. You can learn more about this concept if you study something known as Bernoulli’s Principle. It sounds complicated, but once you dig into it further, it really is not that bad.
Measuring it – How it Works
As I mentioned above, most of the time the unit used is Pascal. However, Torr is another option. We base the measurements on a vacuum off of the natural atmospheric pressure. This is seven hundred and sixty Torr or approximately fourteen Pascal. So, keep that in mind as I discuss this concept further.
Something else to note is that there are two types of systems. These are “others” and “coherent” ones. The differences are not incredibly critical to this article, but I wanted to point this out in case you would like to learn more about them.
As far as measurements of vacuum go, for a coherent system, the formula is fairly simple. It is based on the principle that “F” equals force, “P” equals pressure, and “A” equals unit area. So, the formula is “P” equals “F” divided by “A.” Obviously, you need to know all of those values before you can accurately calculate the figure you are looking for.
Because Pascal (Pa) as a unit of measurement is so small, the bar was invited. One bar is equal to one hundred thousand Pa. The most complex part of these calculations is all of the different units and systems that are used across the world. For example, the “mbar” is the most popular form of measurement in Europe right now.
Why it Matters
If you are not a physicist, you have probably been wondering why this is so important to understand. Well, I will admit that it is specialized knowledge. That being said, if you look at pages like this one, you can start to get an inkling of why it is valuable for many people.
One such is that vacuums are a part of many products, be it in their use or their manufacturing of them. We may not realize it, since at face value it seems to only be useful for cleaning mechanisms, but in truth, it goes far beyond that. One of the primary motivations is heat transfer.
When at surface pressure, heat transfer is usually impacted by the size of gas molecules in the space they are occupying. Taking out some of the guesswork here can be valuable, to say the least, due to the nature of how vacuums are created. Some might argue that it is more trouble than it is worth, but many scientists who dedicate their lives to this field include this as one reason that they continue.
Something important to note is that there can be adverse chemical reactions, so removing any potentially hazardous gasses is quite critical. It is easy for an intended vacuum to be contaminated, so the utmost care must be taken to ensure that this does not happen. If you are unfamiliar with the procedures involved, I would highly recommend studying them further before you attempt them for yourself.
Thankfully, if you are a manufacturer, or trying to become one, there are ways to outsource these things. You could also hire scientists of your own to tackle any potential roadblocks throughout the process. Just remember that there is more to it than in a vacuum cleaner, so expand your horizons a bit!