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Rachel Kaiser gives an amazing presentation on all the stuff we wish we knew to make understanding HVAC science easier for us to grasp.
Read all the tech tips, take the quizzes
and find our handy calculators at https://www.hvacrschool.com/
Stock and Crypto AI Prediction : https://stocksignalslive.com
Rachel Kaiser gives an amazing presentation on all the stuff we wish we knew to make understanding HVAC science easier for us to grasp.
Read all the tech tips, take the quizzes
and find our handy calculators at https://www.hvacrschool.com/
Hi thanks for watching this great presentation from rachel kaiser at the second annual hvacr symposium in claremont florida. She did this remote presentation. Rachel is an amazing scientist. Her husband, eric kaiser, does a lot of education in the hvac trade, so she helps to lay the groundwork on the science that we need to know in order to better understand the hvacr trade very appreciative to rachel and all of the speakers and sponsors for the Second annual hvacr symposium, so here we go rachel kaiser and science.
The way i heard it i'm going to go ahead and get started, and i want to welcome you to science. The way i heard it, i'm rachel kaiser and i'm a practicing scientist. I have been practicing science since i was a very young child and much longer than any job schooling or a formal education variety, or anything like that. So, that's why i identify as that practicing scientist and we're going to talk and explore around science in practice, as well as the theories that go behind it on how we navigate the world around us and how that will then relate to hvacr.
So hopefully this. What do you we're going to start here with our first question? What do you think of when you hear the word science giving you just a few minutes to think about that, because that's going to be part of today is it's reflection and thinking about what these words mean to you and what your experiences have led. You to think about so: do you think of a person wearing a lab coat with a lot of test tubes or beakers in a lab, or do you think of the person? That's diving off the edge of a boat to uh navigate a coral reef? Do you think of something that is physical, or do you think of something that is living, and so those are some of the topics that you want that come to mind for some people when they hear the word science, and so, let's begin by what you think Of when you hear that word so dictionary definition of science is captured here, you can see we're talking about a system, a systematized knowledge in general, so we're looking at an opportunity in which we're systematically collecting information um. It goes back to how skills are reflecting on that application of facts or principles that we gather and then share in a systematic way, and so those will play a key role as we move forward and have our discussion today.
A key piece to keep in mind is hearing versus experiencing, and this is as true in science as it is any other field. You have theory of what you talk about should happen and you have the real world um evidence that you collect is that real world evidence complete, or is it aligning or not? Aligning with the theory that we read about have demonstrated to us through a variety of methods, that's a very important differentiator and oftentimes. The things that we hear help to guide where we go in the future and how we learn about different topics affects how we engage and what we want to pursue as we move forward. Like i shared, i have been practicing science science.Since i was a very young child. I got my first microscope when i was in first grade. I played um bio biology, i'm so sorry, biological exploration throughout my yard. All of the time it was about taking the world that i had around me and putting that into practice and quantifying what i was able to collect.
A key piece that i want to cover before we move on is also something called bias. So if you look here, you see this math equation. This makes a lot of people flinch. If you're it's one of those cases that you're often in the camp for or against something like you see on the screen, that would be conscious bias.
We also have to blend in that. We have both that conscious, as well as an unconscious bias, and that's going to be an important thing for all of us to continue to think about for ourselves, because that grouping of biases is going to be critical. When we're looking at our outcomes and how we can analyze and move forward uh from what we call the data we collect so before i continue, i want to give a quick short story about one of my experiences and the way i heard it when i was In school, so i was put into a challenge class and it was 1986, and that was the year that they were putting the first um teacher into space. As you i'm sure many of you remember, it was the challenger the whole time of challenger.
As far as the actual spacecraft - and i was in a a course at my school and we were going to study rockets now - i was very very excited and um we had our own space, it was separate. We were going to build model rockets, we were going to launch them. We were going to do all kinds of additional study and understanding behind what it took to launch a rocket. What was involved in being an astronaut? What was the pieces that were going to come out from the scientific experiments that the teacher was going to get to participate in from? Because when? From my small town, there was actually one of the teachers from our our school district? That was one of the finalists, and so it was a really big community activity.
As far as everyone was very excited about the upcoming launch and the process in general, so to get to be part of that in the the school itself was very exciting. So one of our first classes about the rockets and how they worked was simply, how does the rocket take off and the teacher stood up in front of us and proceeded to share that rockets launched by pushing off of the earth? Now i at the time was a first grader and the teachers and what they said about how science in the world worked. That was the place where i was going to absorb and they were the experts and i was going to absorb what they were saying. That was the perspective and the bias that i came in with i being a very excited kid after school rushed to my dad to share with him how i had just learned how rockets actually took off they pushed against the ground.I shared with my father and he was irate. He was not excited about this sharing of information. As i was beaming and glowing about what i had just learned. He was aghast he proceeded to march over to my elementary school and find the teacher and share his dislike that they had just incorrectly told a whole group of young students that rockets pushed off of the ground to launch.
There's a couple flaws in that in when you step back and think about it, one, how would rockets ever fly when they got to the space if their movement was actually reliant on the ground? On top of that, it negates the entire principle of newton's third law. Now, obviously, as a first grader, newton's laws were not being outlined in the way that would later learn. But my dad, who was a restaurant owner and uh cook, very clearly said it's like. I may only have a high school education, but i know that rockets do not push off the earth to launch, and i wanted to share this, because this is a piece that ties into the kinds of things that we're going to be exploring further.
Today, it's often how we hear something initially, that plays a big part and let's see, if my ah there we go. So i wanted to step back and do a few takeaways from sharing this story about my first exploration into rockets as a young child and one of the key and simplest is that rockets do not push off the ground to fly. They leverage propulsion, utilizing newton's third law, and that is that for every action there is an equal and opposite reactions, so the the propellant actually is forced out, and it is therefore of the rocket itself and it is the reverse force that propels the rocket forward. Another key takeaway is that what you think about a topic is likely going to change and expand and morph as you get new data and more information on it.
So it's not as simple statements that tend to be what is important in the end. It's actually about painting a more complete picture about what is happening around us. I also learned one very important piece and that questions are good and that even when experts say or someone that is perceived to be an expert, you don't need to accept everything that they convey at face value, question those pieces and do it in a respectful way. When you're looking at some that one that is considered an expert, but that doesn't mean that they have all of the answers and again never fall into the the the trap.
The bias, the piece that says that, simply because a individual has a specific education level that they don't know or understand how specific things work. So this jumps us to going to the basis of scientific, the scientific method which is utilized across all the science fields. To be able to move understanding and solving problems forward, i'm sure that solving problems is something that almost everyone has encountered in some way. So what we have is we have our first step, which is up here in the red box, is where we list our problem statement or our question that we want to answer.That's the first step that we want to ex to frame out when we are starting down a scientific method process. The next one is here in the orange box, and that is where we get the current state. We we start to explore what is the basic understanding of what it is that our question back here framed around: what are the conditions? What do people generally understand about it? It's the context that will start to help formulate our next step, which is our exploration into. What's going to take place and you start to form what you think is going to happen that this yellow box is often referred to as your hypothesis step.
So that's where, like i said, it's iterative, so we take our question. We take move to our orange box, where we look at what our whole circumstances and the understanding that we have, and then we formulate our hypothesis or what we think our outcome will be. Next, we move to what actions are we going to take to test that hypothesis here represented in green and as we go through those actions, we collect data that data then gets analyzed as we move to our next step, which is here represented in the blue box. That's where we analyze those results, and we start on the process of do we have enough data to answer the question.
This then quickly moves us to the final box in the method which is draw our conclusion. Drawing our conclusion does not actually end this process, because what we often have happen is exactly as we have shown here. We come back up, that's data and analysis that we have done actually a spawn. That did we ask the right question: did we have enough information about how the the system or the pieces were actually going to work, and did we form the hypothesis? Any of those steps could have been too broad or were not um, framed in a way that actually allowed us to draw a conclusion that we would be able to leverage to go forward.
So what you do is you go back up and start over with reframing or re-asking another question or narrowing what your problem statement is and then you walk yourself through the method. Yet again you again say: what more now do i understand? Having done this? The first time, what can you add to that? How can you refine your hypothesis? What additional actions can you take? That would continue to build on testing. That hypothesis, was your analysis itself? Was it to broad? Did you utilize too much of a personal bias that led you to see data that was or wasn't actually there? So all of those pieces allow you to continue this flow through the process of asking a question, drawing a hypothesis testing it and drawing a conclusion from that specific set and going through again. So you want to make sure whenever you come into these kinds of situations when you're looking at these methodologies, that you understand what assumptions you're making you're never in when you're in this orange box, uh process for the scientific method, you're.Never in a state where you're going to have full understanding of the entire environment or what people are going to know or what even the system is capable of. So it's important to understand where you're having to make assumptions, because everyone is going to have to make a given level of assumptions and always always remember that as you go through, there's no incorrect outcomes. Every piece, when time element that you go through this method gives you more opportunities to learn about yourself about the system you're trying to gain greater understanding about, as well as how to become better problem solvers now i know that on a slide where you're just walking Through and seeing these blocks it doesn't have, nearly the impact is actually walking through some work around utilizing this method. So we're going to do that now we're going to practice some of this scientific method.
Now, i'm hoping that all of you in some way have available to you some type of a piece of paper. Now it could be as much as a small instruction booklet uh, an actual just piece of paper, something that meets that criteria, i'm hoping that you have available somewhere close to you and then another object with more weight, a pen, a pencil, a sharpie. Some kind of writing implement. Hopefully you have that available because we are going to leverage these two pieces of items materials you can choose whatever word you'd like to use to practice some of those steps that i just outlined in the scientific method, so we're gon na start the scientific method in Action and no you didn't get rid of the colored boxes, they're still with us, so question: will the paper or the pen hit the ground first? This is the simple question that we're going to leverage to be able to see this process.
That is called the scientific method in action, so the current state um for those of you here just write down what you think the current state is, if you don't have an easy way to write at least think about it in your head. What is the current state so i'll? Give you just a few minutes to think about that and then i'll give a few discussion points. All right has everyone, hopefully had a bit of time to write down or at least think about what they view as the current state current state. Let's start here with the piece of paper, i would say it's solid.
It has a lot of surface area um. I mean it's white in this case on my example, but given that my question is, will the paper the pen hit the ground first and i'm just thinking through current state? My piece of paper doesn't have any holes in it um those are the kinds of things that i would start on understanding and then, as a current state, beyond simply that the piece of paper, the material i'm going to use, it's also that i work under the The overarching idea that we are all going to be affected by gravity, because i'm dropping the piece of paper on earth and so gravity will play an effect. So that would be my current state is. I understand that the reason i'm standing here is that gravity is affecting me, so those that adds in to what our current state is and then it would be the same kind of look at the other material i'm going to use um.In my case, i have a sharpie and again solid, no holes less surface area than the paper, and from that we would then move here to the yellow box prediction or hypothesis, and that ties right back to our the way. I heard it if you hear the word hypothesis, which i tend to use. Is that help you think about what it is or just simply saying the word prediction all we need is for you to predict what you think is going to happen when you go back to the question of will the paper or the pen hit the ground first, So write it down, keep it in your head. What's your prediction, so we then move to testing the prediction through actions so we're gon na start the pen, i'm gon na i'm asking all of you to go ahead and stand up.
This is the moment to not sit in a chair, not sit in the seat of your van, not sit at your dining room table, but stand up and participate in doing some of these actions that not only test this prediction but start to make this more of An experience, even if it is something as simple as a pen and a piece of paper. This is the start of how we get to understand the scientific method and how we can use it in day-to-day experiences all right. So the first step we want to do is drop the pen, it's a little harder to see, and it's going to be less helpful. But if i drop this pen it felt i'm going to go on a limb and hope that your pen also falls.
I cannot see if your pens are falling, but hopefully they are. We will then move to the next step where we have the piece of paper again we're going to move to dropping just the piece of paper all right. Our third and final action, step after we've, retrieved the pen and piece of paper, is we're going to drop them at the same time. Now we want them to be as close to being dropped from the same height each time, we're not going to time them.
We, this is not about the exact accuracy of a measurement. This is about what we can observe with our eyes, because most scenarios are dependent on our observation and data collection as individuals. It is the addition of instrumentation gauges and a lot of the tools that we use in various scenarios that just add to the data that we're able to collect to narrow down the kinds of actions and data analysis that we're able to do. But in many cases you can do it simply with what you have, which is your eyes, your ears and your sense of touch so we're going to bring our items at roughly the same height and we want to drop them at the same time.What happened again think about that write it down if you can, or at least hold it in your mind as to what happened, if you want, you can drop them again. If you didn't see, i did not watch my paper and pen on this time. I have to admit i looked at my slide, so i am going to do it one more time, so paper pen drop all right that time. I actually watched the items fall, so i was able to collect data from the actions that test our prediction.
We now move to that next step in the scientific method, where we analyze the results, so the first piece goes back to dropping the items individually, not looking at it as a comparison. Did both items fall to the service below them? This cycles, us back to that understanding that we talked about in the the orange box of working under the assumption that we have gravity acting on us and the objects around us. Did you notice anything throughout the process of dropping the pen, the paper individually or together? That was unexpected. Did your piece of paper waft in a way that you didn't think would take place? Did your pen somersault as it went down um your options of what you saw are open and limitless? What were your assumptions? We covered one of those assumptions.
The idea that gravity was still going to work on all of our objects. That's still an assumption. It's not one that many of us ever get to break free of, but it is still an assumption that gravity is going to work. How we have always historically interacted with it, so our final piece for round one of the scientific method is drawing our conclusion.
This brings us to that third test step where we drop the two objects together, which item hit the ground? First, where did you have places for error or bias? For instance, did? Did the two items actually get dropped from the same height if i drop them like this? Is that a cause for error? Is it bias that i'm already anticipating that the pen will fall faster and hit the ground first? So i'm giving the paper a fighting chance? Those are the kinds of things that would allow for bringing in error or bias during our experimentation step that affects what our data is and what kind of conclusion we can draw now. I can only speak from my experiment but in my case the pen, my sharpie, hit the ground first, but we need to be ready to iterate and continue to build on this process and we want to test those assumptions all the time. So our assumption - because i showed it that way - was actually that this piece of paper was flat. I never said it had to be flat.
If this piece of paper is now a ball, is it going to fall at the same rate as that flat piece of paper versus our pen? We don't know until we experiment with it again, and that is the part that the scientific method gives us all kinds of opportunities to iterate and repeat so that we can better understand. What's going on around us, our next step, a way to iterate what? If we change not just the physical appearance of the item, what if we change the items so based on what we just studied in our experiment, we go back to a new question which hits the ground first a feather or a bowling ball. As you can see, i have jumped from the red question. Orange is going to be very the orange the understanding our situation, the world around us is something that many times people want to skip.What is it that we know about the system that this test is going to take place in? What are those pieces going to be? What do we actually know about the bowling ball and the feather? That's something that you want to have play into what your hypothesis or like i said this - is your prediction so again in this iterative state? What's your hypothesis, what's your prediction between this feather and bowling ball being dropped when you get to the analyze, what you see is whether we look at the first part of the video where they dropped the bowling ball versus the feather. Just like we did the paper and the pen or when the second part when they put the room under vacuum and drop the two. So our conclusion changes because they iterated in that video so which item hit the ground first depends on which iteration we want to look at, and it comes back to understanding the world that we are looking at and where that data is coming from, because if i Only had shown you, the second part of the video, and you were not given the details that they had pulled that room down under vacuum. What would your conclusion have been? What would it have been? What you had expected? The likelihood is not because would have would one of your assumptions have been well, it would be in a vacuumed room that starts to help.
Tell us where we need to watch out for places that we can have error in what we have going on around us. If you want to call it error, if you want to call it bias, if you want to call it not understanding what it is that we're working with, and that happens all the time - and that is one of the the key learning points is knowing that we Aren't going to understand everything that that environment has and so um it's key to take that and be able to work through repeat the process, because, hopefully we run into scenarios where the answer isn't what we expected, but the other part to just highlight is what the Video does is, it shows us the difference between what we typically experienced in the real world, which is the bowling ball, hitting that crate long before the feathers ever came versus the theory. If you sat in a science class, the theory says that the two should hit at the exact same moment, because it's only because of the air resistance in which the feathers or in our earlier experiment, the piece of paper falls more slowly and that's something that we All need to keep in mind, because the way we hear things, often in a formal science class, is all formulated and tested against theories that don't necessarily have the same experience when you put them in the real world and that's what we need to realize makes a Big difference at being able to leverage the theories in a academic sense versus leveraging them in a meaningful way in the world in which we all work. So this is another important takeaway um in the case, if you had of our bowling ball and feather, if you had said the bowling, ball would hit the ground first, and you only saw that second half of the video where they hit at the same time, you Could easily move to the conclusion that you were wrong and that that incorrect hypothesis or incorrect prediction was bad science and that's not true those bad bad.The incorrect data are great opportunities to learn and are critical for us to actually build not only a better personal ability to solve problems in the future, but actually to grow the entire um approach to how we experience the world around us. And so that's why i most much appreciate this ralph waldo emerson quote in which bad times have a scientific value. These are occasions a good learner would not miss. So, let's always make sure that we take those bad times and learn from them, because they all have value when you iterate and use the scientific method approach to solving the questions and problems that we face every day, all right.
So i've been talking a lot about the scientific method and about how we can know about air resistance, and i've talked about some rockets and all the kinds of things that are probably pretty. Typically things that you might consider of a science class or a chemist, or a physicist or an engineer, but what about why, as hvac professionals, hvcr professionals should you care about this scientific method? Does it matter whether you hear something or experience it as i've been demonstrating with the bowling ball and feather hearing about a theory of how those will fall versus experiencing them in the the real world, not in a vacuum? They have significant differences in what the outcome will be, and here we're going to do is we're going to take the day in the life of an hvac technician and see if that really is still a day in the life of a scientist. So, let's explore that a bit more and we're not going to leave our scientific method behind what we are going to do is we're going to make two changes here, we're going to stop referring to it as simply the scientific method and we're going to start calling It the problem, solving method, because that helps to not just take what we have heard over and over and transition it to something that i'm sure almost all of us have had of. We have a problem.
We need to solve it. That problem, then, is what do i have before me. What do i think needs to take place? I then follow through on those actions. I see what is the outcome, and then i decide whether that fixed my problem or if i need to do something more if that sounds familiar, that is the problem solving, which is the same as the scientific method we've been talking about.We're also going to take this problem-solving method and apply that to a question around hvacr, no more rockets. So here's our question is hvacr a science now just to be sure we're all in the same uh playing field. I have a few definitions: hvacr is still heating, ventilation, air conditioning and refrigeration and science is still skills, especially reflecting a precise application of facts or principles all right. So that's where we're going to leverage these definitions related to is hvacr of science and now we're going to walk through the different steps of the problem.
Solving method for this question: are you ready to go all right, so we've moved to our current state and understanding. Hvacr is typically considered a trade. Would you agree, ironically, the department of labor does not even classify classify hvacr as a skilled trade. Despite that uh, the list that you see is only the start of the many areas of understanding that so many roles in the hvacr broad field require for executing successfully.
Because you don't want to end up being like george over here and looking at a pile of thermostat wire and not having any idea what to do. His problem may stem from not having opposable thumbs, but i think he was also lacking some of these critical abilities of being able to understand electrical or even work the tools. So that's where our current state and understanding from an outside perspective of hvac are a trade. But is not the reality that so many base concepts across such a diverse set of often trades carpentry, metal, working building shells written and verbal communication, all of those pieces play into what you have to do as hvacr professionals.
So our prediction: now i have filled out the prediction that hvacr is a science that is the hypothesis or prediction we are going to walk through test for and against analyze and draw a conclusion from because remember, science is nothing but perception, so the department of labor May say it's not a skilled trade, but we're going to see if we can show that hvacr is a science all right. So we have two keys areas here in the action portion to test that prediction to see. If hvacr is a science, now we're gon na start with the survey portion in this part of the testing we're gon na, i have already gone and asked a variety of people with diverse backgrounds with different work. Experiences different education levels, different parts of the country.
What science, by definition, is to them? What we will then do that test is seeing if those perspectives of a diverse group of people matches with the work that is done in hvacr, so remember, they're defining what science is and then we're going to analyze to see. If those perspectives match the kind of work that gets done in hvacr traits, our second is we're going to explore. One topic we have limited time and the options are pretty large, but we're going to take one topic and look at that topic that is applicable to the hvacr fields and compare how you usually experience and hear about that topic in a a typical science classroom versus Utilizing the the topic itself as an actual hvacr professional. So let's get started with the action portion.We will start on the survey and in case all of them will be marked as to which portion of the action we are covering at the moment. So our first survey is actually comes from what science is from a high school math physics and chemistry teacher. So they think that science is the study of how to understand the world around us through different lenses of thought, for clarity in understanding ourselves and our world. Does that resonate? Is there parts of that that feel that you think have application to the kinds of things that you do as an hvacr professional all right? Our next comes from a commercial hvac service technician.
It's everything. Science is the human endeavor to understand nature. There are rules that must be followed. One must base ideas on data or information that can be tested by others.
Ideas are rejected if they fail to support what is known. Our next actually comes from a research scientist. They have scientists in their name. I take that and remember what we want to apply for biases in the different roles, a rigorous approach to gaining understanding that allows us to get as close to the truth as possible at any given time.
The product of science is the currency with which progress is purchased. Next, we gather some uh definition of science from an hvacr trainer. They say the ever evolving study of the world around us. Do you feel that that has relevance again to the kinds of activities that you do on a daily basis as hvacr techs professionals? Any of those roles in the the wide field that is next um? We have the definition from a sociological mapper.
They say the process of understanding and explaining things using observation and experimentation from a residential hvac technician. They provided the definition of science as being science is the study of all living things. Our next data point comes from a retired service technician in the electronics industry, and here they say, science is a body of knowledge that can be summed up as widely based on animal vegetable and mineral, though they aren't mutually exclusive. The overlying condition is that the knowledge that is gained and or known in these areas can be verified by facts and can be measured.
Our next data point comes from an hvac control systems designer their definition of science is. It is the way we structure and format data, so we can understand and process how things in nature work. It is by measurable and defined means to track and record what we explore during the seeking and testing of our hypothesis. One of our last data points comes from a mechanical engineer, in which science is the methodology for how we learn and discover the world around us through answering questions and solving problems.So this brings us to analyzing these results and we're parsing this out, because we have that two-prong approach. We have the survey data and the topic. So our first piece is the survey and what is science? I captured a few pieces as takeaways because i do not expect people to memorize those quotes from a variety of backgrounds as we went through them. Many of them referred to nature the world around us as being critical.
Do those topics the world around us? Does that not apply to hvacr a next uh highlight many of them mention study or working to understand again going out. Does an hvacr professional also work to understand, what's happening with a system uh refrigerant a um, even just as a teacher of the the skill set you're working to understand what it is that your students need all of these seem to fit under studying and understanding the World around us and then one of the final points, many of the the survey uh respondents had measured measurable around facts. So does this also apply to hvacr? Do you not leverage a variety of tools and instruments to collect data and measure how a system is performing? Do you not rely on facts about how something is supposed to work to be able to help guide when you are problem solving or going in and trying to fix an issue that you have arise with a piece of equipment? So this does bring us do all of these topics tend to apply to hvcr all right. So we're back to our topic and just to remind you, we are in their action step around looking collecting the data that will determine whether hvacr is a science and we're working on the prediction.
That hvacr is a science all right, so you'll notice that one piece i have gas laws in quotes because they're gas laws and the term laws often has a very um clear definition that pops into people's minds. So that's something to keep in mind, because that falls into the way we hear it versus the way we use it all right, so we're gon na take a little bit of a trip on these topics into a science classroom. Obviously this is my one of my comfort areas, just like that math equation. So it's important to understand that that's part of my bias is that stating historical facts about the scientists that came up with these laws or theories is part of what gets me excited is understanding the context and the time and the limitations that they had of of What they could experiment with and still draw the kinds of conclusions that we use so we're going to start here with boyle's law.
This is robert boyle scientist from the 1600s and he is the one that worked out the relationship between pressure and volume. Now, before we get any further, the key here is: these: are gas laws now, let's take out the laws and let's call that theory, but they still are the gas theories, so we aren't talking about relationships that are going to work if you switch to a liquid Or a solid or any of your fluids and the pieces where you start to have multi-phase of a particular compound this and the what we're going to continue to talk about. It's important to remember we're only talking about these theories applying to gases, so boyle figured out that pressure and volume were related and inversely. So essentially, what we have is shown on a graph and gets even better when we pull out an example.Probably reminds you of something: if you went through a lot of regular science class examples, something you'd see in a regular textbook. Look, you have a bunsen burner, it's heating, a given uh vessel. It has molecules of a substance at a given amount. So in this case, our problem is listing 17.5 milliliters of a particular gas and it's at 4.5 atmospheres all of these in units and and um vessels, and things that don't necessarily apply or come up in a real world experience.
I don't know about you, but i do not go up and see if the pressure outside is measured in atmospheres, typically to see how the day is going to be, because that's going to be a key thing to keep in mind. As we continue to talk about these because temperature in these theories, it's critical that they be in specific units for the relationships to be comparable, so we walk through. We have this example, and you end up with an equation in which your pressure of your second vessel times, the volume that you have in your second vessel, is equal to the pressure in your first vessel times the volume in your first vessel and if, in a Class setting you probably get to do a lot of problems leveraging that in which you plug in numbers, that the question, above from the textbook, provides you into the appropriate spaces and you solve for the unknown entity. And it tells you with the fixed amount of gas.
Er, what's the temperature, because we know the other values? What does that tell us about how to use that in the real world? Are you going to have a static system in which the amount of material doesn't change, and these beautiful bunsen burners that allow uh your temperature to always stay exactly the same and somehow magically? Even in this theory, this bunsen burner keeps the entire space at an even temperature. Does that seem realistic? So this is the example and the kind of problem you'd work in science class, but it doesn't feel that it works very well in the real world. We're going to continue on because boil was only the first gas theory. Now we move to charles, so we've jumped from the 1600s up to the late 1700s, and here we have charles law, where he figured out that there was actually a correlation between temperature and volume.So here, when you get your temperature increasing your volume increases and gets represented by a graph as this nice vertical line, which, by the way, if i s goes up so and a key part to remember, is once again we are showing that our temperature is in Kelvin, not your fahrenheit, that you often have it's not even the celsius that many scientists or europe or canada, actually all leverage either it's a switch that you have to actually change the temperature to to do these science class uh math calculations with the key takeaway becomes Volume is directly proportional to temperature. Again, though, it works the same way. You end up with a textbook style question, setting up the scenario that charles had tested with magically other components amount, and in this case, when you have temperature and volume so pressure as well as amount are being held. Constant, are those real world applicable all right? Our third one, we move up to the hundreds here we have gelusak and his experiments where he built on the work that charles had been doing and figured out that there was actually a correlation between pressure and temperature.
But again it's as long as we hold l else, constant, so volume doesn't change and amount doesn't change and we still have a direct, proportional relationship of one goes up. The other goes up here. We have another example where we get a beautiful equation. You do a lot of plug and play when there's solve for a given piece and figure out what the pressure is.
Wonderful and again the handy, dandy, kelvin, taking the relevance of this law or honestly theory and applying it and every one of these. The piece that's critical to remember is it has to be the gas in a so in this case aerosol can it doesn't work when we don't have only a gas, these math equations, so is that the relevant way to bring it for an experience standpoint? We don't stop there, though. We then move to taking boyle charles and gillusax laws theories and combining them together to do the combined gas law this in one one equation. We get the relationship between the temperature, the pressure and the volume, but again the amount is held.
Constant, how many real world scenarios do we have in which the amount is never changed. It's a closed system in which your amount cannot change. There are examples, but they are not um large in number outside of control, where you're intentionally setting them up. That way, you get to do some more math with another equation.
That now has the temperature, the volume and the pressure, and everyone still likes in science class to refer to it as the law, but that law is so narrow in its scope. You're still in an ideal, it also is an ideal gas that is being leveraged to be able to calculate these um problems out in true form. We just keep building, we add on avogadro avogadro was working separately um from the the gas laws in which he expanded around the relationship that you have when you have um when you're looking at a gas and the volume and this piece, his approach makes two key Assumptions where you have temperature and pressure constant - and this is the first time that we actually bring an amount into being variable. So here, where you have two and in this case mole is the amount.It is the um amount of the molecules, and you add it to how met the amount in this case of oxygen. You then only get two moles of water, because the moles isn't how many atoms it's. How many molecules sure this is exciting, because now this is the key part when you're looking at amounts is that number of moles? Is this fun greek letter that looks kind of like a long, legged n? That mole is the amount of any substance and it's based on 12 grams of carbon 12., not carbon 13, not carbon 14. You have to compare it against carbon 12..
Now, i'm not sure about you and your typical um interactions, but do you ever go and analyze? How much you have of something versus carbon 12? Even i don't do that in my lab. One mole of that substance then garners a particular constant, and that is known as avogadro's number. So when we're looking at this from this perspective of from a science class, you end up doing a lot of these examples, leveraging avogadro's number 6.02 times 10 to the 23rd, and then it's always the did. My teacher allow me to have that on the test before we took it, or was it something that you had to memorize? Does any of those questions apply when we're looking at real world experiences? You continue, you bring avogadro's number you bring in how many moles and the volume, and you again get your equation.
You look at these situations where you set up for this ideal gas and you play the math game and you figure out that. Oh, that relationship means that they're directly or indirectly related that's what it's telling you so now that we have addressed the relationship between temperature pressure volume and number of moles. We get to jump to the ideal gas law or theory. Let's call it the ideal gas theory.
Now the best part of this is ideal in its own utilization is just that it's the theoretical gas. So you have the theoretical gas theory. Does that sound particularly useful of an equation? I'm going to? Theoretically, i'm going to have a theoretical gas theory. It does bring a lot of questions so here what we've done is we've combined boyle's, charles guy lucks and avogadro's approach and relationships about ideal gases and put them in one place, some key pieces.
We still have the issue that temperature always has to be put into kelvin, because this crazy r, the gas constant, requires the use of temperature in kelvin. This works. This theoretical gas theory still has two key assumptions, and that is that the atomic volume itself is ignored and that you have no intermolecular forces. Those are critical and why it is really the theoretical gas theory.So as we continue to build and we walk through the science class and we're doing all the gas laws, we then come to dalton's law, or often referred to as the law of partial pressures. This is where you take one gas that has a given pressure. It is actually additive to the second gas. That's in that system for a total gas pressure combined from those two.
So your equation, depending on how many states you have is your total pressure - is dependent on every pressure of. What's in that system from a gas standpoint, the key piece here is you then get to do a numerous iterations and then there's this point of. We already know that this theory of partial pressures breaks down at high pressures and low temperatures, because when you hit those areas it takes gases further and further away from being ideal or theoretically relevant. So then, our class, our science class here, is moving us to real gas laws.
This is sounding better because i've brought up over and over what we have is we have these ideal scenarios and these theoretical gases acting in a relationship. So it's the late 1800s now and we have van der waal and he worked out a way to explain why gases were not matching up with all those previous scientists work. That said, this is how gases should behave. So van der waal came up with an equation because that's what you do when you're iterating in this case they had these equations from charles and boyle and gillusak and avogadro, and you put it together and then you run into the problem with dalton's partial pressures and It breaking down at those high pressure scenarios or low temperature scenarios, and how do you explain that so van der waal added a correction factor so now that pv equals nrt equation? Now has some correction factors so correct for the attractive forces that we are between happening between the molecules and correct for the volume of the particles themselves, giving you the ideal pressure times.
The ideal volume is the nrt. That's what we're used to that simple, combined uh relationship now just got a lot more complete complex, because do you have an instrument that figures out the attractive forces between molecules? How about the volume of particles? That is not an area that many people can just pull out of a bag and measure. So this is where our science world meets the real world. Our ideal theories, what we've been looking at with all of these advancements through the 16 17 and 1800s, was based on the same concept as looking at earth as flat to be able to work out how the the gases related the pressure, the temperature.
All these things. They needed to make a set of assumptions so that they were able to have a data set that allowed them to draw a meaningful conclusion, but they had to make a lot of assumptions. This is what led us to ideal or theoretical gases, because there's almost nothing in the real world that fits into that ideal. You then move that the earth is not flat.Sorry, if i just burst someone's bubble, it is spherical, and this is our real gases. They are complex, they have dimension and they don't behave as if they're flat. This is where those theoretical gases and the math and the pieces that we've just been walking through break down, but those gas laws. Those gas theories have real world correlation, but it's not about taking those pretty textbook pictures and doing some math and seeing what the volume is going to be.
That's not going to be applicable or value added to anyone, a scientist that works in a field or a scientist that works in a lab outside of that classroom. Setting those ideal gas laws are about their relationship and not about the graph, the math or the the pictures on um unrealistic expectations of assumptions. So we're going to come back we're back at boyle's law, so we're back in the 1600s and our the fact that pressure and volume are inversely related now, a piece here when we start coming to real world volume in these cases is often helpful to think about. It's the space between the molecules.
It is not in the same sense of volume that we would think of a vessel. Think of this volume that oil is referring to is the space between the molecules. So if we move to the idea of a nitrogen tank and you're in the process that you're wanting to fill a line set in coil and with your nitrogen tank, you have a pressure. Reading on that tank, you um, have you re use the nitrogen and you start filling your line set in coil.
Your pressure on that gauge goes down now we're going to only look at the gas, the nitrogen in the tank that nitrogen in the tank as the tank volume is going down. The space between those nitrogen molecules inside the tank gets larger. So your pressure that you're seeing on the gauge goes down, but your volume of the gas which is in this case the space between the molecules is inverse. It actually increases so your space between your nitrogen molecules in that nitrogen tank gets larger because your vessel, the tank itself, did not change size, but the nitrogen gas left in the vessel did not um just hang out in a little corner like an introvert.
It filled up the nitrogen tank, therefore increasing the space between the nitrogen molecules, and so it's those kinds that this relationship is applicable and helpful to know without ever needing to do any math. It's just as your pressure goes down. Your space between your molecules goes up. The same is with charles law.
Here. Remember: charles 1700s volume is directly related to temperature in the real world. Do we care of temperatures in kelvin? No because it's about the relationship that, if you increase volume, increase temperature or if you decrease volume, you decrease temperature and again we want to think of this volume as space between the gas molecules. Because in these scenarios we have to also remember, we are still only talking about gases.So if you look at your air flow testing of a furnace supply in return, when you have your temperature increase your space between the molecules because they have now heated up, they are acting with a lot greater energy and movement and that moves the molecules themselves further. Apart, increasing the distance between them, or sometimes referred to as the volume of the molecules, it continues, because obviously, temperature we know from the late 1700s is related to pressure. So here, if you have a refrigerant tank, that you filled at 70 degrees fahrenheit, because is that not typically a temperature unit that in the real world in the united states we use? Yes, do you need to convert that 70 degrees fahrenheit to celsius or kelvin? No because this is about the relationship, so you fill the refrigerant tank and the gas in it is it's in a gas form, predominantly we're going to only be considering that is placed in a truck and that truck gets to 130 degrees fahrenheit. What happens to the pressure in the tank? This is where the gas theories are going to be very helpful for you.
The pressure goes up because we know from the 1700s that they are directly related. Temperature goes up. Pressure goes up. We have 70 to 130, so the pressure in that tank is going up.
So you have to take that into consideration when that refrigerant tank gets filled. That comes down to the safety, the the dot regulations, everything you have about putting items in a truck boils back not sarcastically to the the gas theories and why those pieces are in place. So it's about the relationship. If we take here and we, we combine all these pieces - and you look at the combined gas law approach, where you have temperature and pressure and volume able to change a txv or a thermal expansion valve - is a perfect example.
Now this is real world, so we don't have only gas. We know that liquid can come through, so you still have a case in which your temperature pressure and volume as it works through your valve follows all the relationships that we would expect through the combined gas theory, even in the real world, and those are the pieces That we can then leverage to make them applicable for a real world experience we take all of those, and we come back to ideal gas and filling a refrigerant recovery tank. It's the same piece as we just walked through for the truck example, you're filling that recovery tank, these relationships matter, it says ideal in the fear. This is the theoretical gas, but when you take that out - and you only think about gas theory and think of them as relationships applying those to filling a refrigerant recovery tank helps, you be safer and understand where the rules and regulations around weighing and understanding those.The pressure changes and what can happen on storage and these things start to fall into place. We move to dalton and his law of the partial pressures where we need to remember that all pressures are additive. So if you have a contaminated system and you fall under a poor evacuation practice and you have a value that you think that you have hit as far as a pressure for your system, that pressure is not simply related to the refrigerant that you were trying to Evacuate it also had the component from the contamination so that value that you're getting no matter how accurate or good the the device is that you're collecting that pressure on the contamination is giving you false amount, because the pressures are additive and that's a way that you Can see that again, this theory around an ideal gas that is not actually available in our real world can still help you understand and think through some of the pitfalls that you can hit as to is this a system that likely has contamination, and what does that Mean then, to my pressure value that i have actually coming through on my measuring devices, whatever ones you use last piece here: real gas behavior. This is what helped to spark a lot of the work when you added in the information and the correction factors on the theoretical side, because this is where you can see right here.
The red line is representing what an ideal gas, if we just did those math and all those science classroom examples i gave this is how it would map out you put a real gas, which is what we all have to interact with, be it in an actual.
17 thoughts on “Hvac science fundamentals w/ rachel kaiser”
Great videos really enjoy them
I have a question about the conference videos I purchased a ticket and watched a few of them but didn’t get to finish. Can I reopen these videos or do I have to purchase another ticket Are you in Orleans ?
How get traning in HVAC in USA please help me… I want to learn more in HVAC system…. Plz help me
I feel like she's trying way to hard to convince us she's a "scientist"
Great explanation of the gas laws. Thank you for this Bryan and guest.
Im brand new to this field and just went to school and struggled some so i hope these videos help.
This video was like slow torture.
She identifies as a scientist Are you in Ottawa ?
12hr of running calls: feel good, much energy
2 minutes of listening woman speak: very tired, horrible ache
If you guys are watching this video while driving to your next call this isn't the one Service area Kanata??
Painful, feels like a brainwashing course.the only feelings I care about in HVACR is what temp my hand feels.
My hypothesis is this video could’ve been broken up into 2 parts
#1- 43 minute discussion on the scientific method
#2- could have been a discussion on the gas laws. It starts at 53 minutes in.
The 10 minute transition segment was a bit much for me, as was the summary at the end.
HELLO…HOW TO LEARN CONTROL WIRING AND READING ELECTRICAL DIAGRAMS. I AM MECHANICAL ENGINEERING GRADUATE
To the people who are complaining…if you don't like the free training you don't have to watch. Be respectful like it's your family member. Any truly knowledgeable person in any field needs to have solid fundamentals. Only with a sound foundation can you build your knowledge to the 🌙. To the speaker, thank you for your time and insight.
In the late 19th century there was a movement, Mind and Hand, that sought to bring practical to the theoretical that schools taught. The schools train how to write and speak about a topic, but ignored the training of the hands to apply the theory. Likely from where the increasingly defunct vo-tech courses came.
The stereotype scientist works with novel ideas to find new technologies. The engineer designs useful things with as few novel ideas as possible. The technician, the tradesman working in a useful art, applies the scientific method to their problem solving, but with a big dose of "art" since nothing is ideal after the system has been installed for a few years. The tech must balance those elements the scientist discards when they are looking to mathematically explore the ideal so that the systems work as well as possible in the real world.
Look for the writings of Charles Ham on Mind and Hand, the co-education of the mind.
Thank you so much for Bringing strong information
God bless you and your family 🙏….💯
Omg, ! She drabs endlessly!
I’m only about 10 minutes and 38 seconds in and I already don’t believe this lady story.