AV Geeks Lunch 5-17

Yeah. Hello everybody. It's Kid Alzheimer. Welcome to the AV Geeks lunchtime streaming show. It's very bright. Um I've got some new reading glasses that were supposedly uh low glare no glare, but guess what? They're glared. Um so I'll try to position my head and make this work. Anyways, um Yeah, I hope everybody had a good weekend. Um I hope you're also ready to watch some 16 mm films. Uh that last film was from the Oregon archive. We scanned a bunch of films for them and are actively still doing that. Hope to do some more um in summer. Anyways, that was amphibious craft and it was just some raw footage. We didn't quite know uh there was no title. It just kind of raw stock of an amphibious vehicle. Um, so really no information beyond that. Um, this next film is also from uh, Oregon Archives and based in Pittsburgh. Uh, this is Everybody Knows and I have not seen this and it is by the US Chamber of Commerce, which I will just guess is given the time period, is probably anti-communist and pro free enterprise. Um, because that's what the US Chamber of Commerce is all about and not so much about the the rights of workers. It's more about the rights of businesses. Um, so they actively fought the 40-hour work week. They said they were like, that's anti-business, that's socialist. So, um, here we go. Everybody Knows. Believe me, thinking is the hardest work in the world. It makes an 8-hour day seem like child's play. I know what a man goes through as he begins to change his mind. I I know it doesn't just happen overnight. No, not in a week or a month or a year. It takes a lot of months and a lot of questions before things begin to make sense. I've been bowling with the boys every Thursday for as long as I can remember. Great bunch of guys. Each with a mind of his own. On certain matters, there's never any disagreement. There's certain things everybody knows for sure. Just like everybody knows his own name. And we were pretty sure of what we knew. Dead sure. Right up until the very moment we were hit by disaster. That was over a year ago. Many of us are still trying to figure out how our company went broke. Thanks to the boom, some of us found other jobs after a while. But still the sight of that empty plant stayed with us. You couldn't just blink your eyes and make it disappear. There it was. A great big unanswered question. Something for a man to think about. You talk to maybe a hundred people and five say something that sticks in your mind. Almost a year goes by and gradually, bit by bit, you find yourself thinking something quite different from what you thought when you first started. Hi, Bill. Morning, Jim. Well, there's the rest of the day. Take it easy on me, will you? Prices are what they are, I'm going to have to have another wage increase. Yeah, that seems to be the general attitude. But attitude should change with the times, Bill. There's certain attitudes about wages that belong to the past. Everybody knows a fatter pay envelope each year is good for business, Jim. Give a man more money, he can buy more. Only each wage increase does cost somebody something. Money doesn't come out of thin air. Well, we earned more fair and square. Sure you did, but don't forget, other people paid for it. That's because we produced more. As much as your wage increase? That's the question. Which was settled in fair and open negotiation. Well, I don't know anything about negotiations. All I know is food. All my life I've been peddling foods. And after all, what's the difference between running a grocery or a factory? They both have to show a profit at the end of the year, or you've had it. Everybody knows that. But, does everybody act like they know it? You guys act like profit is a dirty word. Year after year, I hear you say, "We got to get more money." And year after year, prices go up and up. Then in walks your missus and complains about the price of this and the price of that. What's one got to do with the other? Plenty. When you guys ask for more money, you get it. Every year, regular as clockwork. But when I ask for more money, that's something else, huh? Yeah, look. Take this package here. The man who makes it, he gets more money. The people who make the box that it's packaged in, they get more. The guy who trucks it here gets more. And I have to pay more for it, year after year. So? So, in walks your wife and wants to tear my head off when I charge another 10 cents a box. A profiteer, she calls me. Me, a profiteer. Oh, believe me, brother, that's rich. I have never charged so much and made so little in all my life. Still, you're getting another 10 cents a box. Yeah. Another 10 cents that walks right out of my cash register into the pockets of every man who had anything to do with making or delivering that package. And they in turn have to spend that extra money in the higher prices they're paying. So, in the long run is anybody really better off? It was a couple of weeks later that I met the former president of our local union. Now, they don't come much brighter. Still, even he had a hard time explaining why we lost our jobs. Look, Bill, my job was to give you guys what you wanted. Well, we never wanted that to happen. You think I did? You know what my seniority is now? One year. And during the 10 years I was your president, did I ever let you guys down? You wanted higher wages, right? You wanted more purchasing power, right? That's why you elected me. Everybody knows that. And if the company hadn't have gone broke I'd have got you an increase this year, too, believe me. But that's that's not what I'm trying to figure out. Well there's just no simple explanation to why the plant closed, Bill. Well, I know it's not simple. There's so many things related to so many other things. All acting one upon the other. For instance, for instance, a lot of things. The price a customer pays the cost of making the product the wages a company pays the profits a company needs to stay in business and productivity. That is what each of us produces in a day. They're all tied together. Oh, I don't know all the answers myself, but somehow this thing called productivity seems to be the key to the whole question. It's that complicated, huh? Yeah, seems to be. And there's lots more to the story, too. Nobody wants inflation or higher prices, like the times we've all heard about when German marks or French francs or Chinese yen were worth about a dime a bushel. Nobody wanted the company to go out of business. Yet we seem unable to prevent things like that from happening. Supposing we didn't get that last wage increase, could the company have survived? Look, Bill, I'm no accountant. My business was simply to get you boys higher wages, no more, no less. And that's how it went. No matter who you talked to, there just wasn't a clear, simple answer. Well, hello, Mrs. Donald. Oh, why, hello, young man. A cup of black tea, please. Real old-fashioned winter. Mm. Certainly is. Hope it doesn't hurt the turnout tonight. A little snow never stopped people from coming to a church social. Never you fear. I certainly hope not. People haven't changed that much since I was your age, young man. Well, I guess they haven't. Nothing really changes, after all. That's a strange thing to say. Well, it's true, isn't it? Even in this day and age, companies still go broke. Yes, I found that out. The company I had stock in went broke. No. I used to work there. I heard you were a stockholder. That's true, I was. But you see, like most other stockholders, some of whom even worked in the plant, I only had a small investment. Oh, please understand. My husband thought he was leaving me well provided for for the rest of my life. But with this terrible inflation, everything became so expensive. I could hardly make ends meet. You're a well-to-do woman, Mrs. Alden. Not really, young man. Not with this inflation. When they stopped paying dividends, I didn't even have enough income to live on. I just had to sell my shares for what little I could get. I'm sure that those who bought them lost all they invested in the company. I lost my job. And I a great deal of money. But costs were so high. The company couldn't sell enough at the price they had to charge to cover the higher costs. So, they simply went out of business. Several months later, I noticed one of the old company's top salesman was now in business for himself. I stopped to pay him a visit. Bill, customers just won't pay for something they don't get. Each time you fellows got another wage increase, we had to raise our prices. The simple truth is, our customers weren't getting anything extra for the additional money we had to charge them. Well, then we shouldn't have jacked up our prices. Then how could we pay for our wage increases? Somebody has to pay for them. And that somebody is Mr. John Q. Public. So, why didn't the company take the increase in wages out of profits? That's just about what they did, Bill. They added increased wages to costs until there wasn't any profit left. And you can't keep a company going without profits. Profits have to go for improvement of the plant, the machinery, for development and research of new products, to pay the people who let us use their money, that is the stockholders. It's added costs that boost prices. Not only cost of our own wage increases, but everybody else who demanded and got more money, from the man who dug the raw materials out of the ground to the retailer. And it got so bad that after a while we couldn't sell our products for what it cost to make them. Well, everybody knows higher wages are good for business. You pay people more, they can buy more. Everybody knows that. Sure. Sure, everybody knows that. Until they find out something different. And so, that's how it was. More months went by. Fortunately, in a small town you finally get to meet just about everybody. One night at the end of a PTA meeting, I introduced myself to the president of that company. Well, Bill, that's a tough one to answer. You can't isolate just one thing or one economic factor and say that's it. That's why it happened. Everything's related to everything else. Connected, sort of. What one group does seriously affects the others. You're the second man to tell me that. The former president of our local union told me the same thing. Well, it's true, Bill. Shouldn't take two ex-presidents to convince you that during a boom, people go along believing you can raise wages indefinitely. Just keep increasing purchasing power and everybody's better off. The great American dream. Only for us it turned out to be a nightmare. A nightmare because we lost sight of the essential truth that higher wages are good when they're the result of greater output per worker per day. And most increases in productivity are the result of profits being used to buy new machinery. So we can produce more goods and make jobs easier and safer. We got into trouble when wages increased and output per worker per day didn't go up as fast. A vicious circle. Exactly, Bill. We were running a race we couldn't possibly win. Wages went up. The increased output per worker per day that would have enabled us to pay these higher wages lagged behind. Lagged behind because we weren't making the profits needed to buy the machinery which, properly utilized, would have enabled us to increase output. And because of this lack of profits, stockholders and bankers were increasingly reluctant to let us use their money. And when we stopped paying dividends, we're just about through. Each wage increase, whether to our own employees or to the employees of the companies that supplied us, just accelerated this process. But we just had to have more money. You know what's happened to the cost of living. I know, Bill, but you get inflation every time there's an increase in wages unjustified by an increase in productivity. Every time, sir? It's one of the economic facts of life, Bill. Higher wages are good as long as they're truly earned. As long as they produce some additional value that the customer's willing to pay for. And when wage increases are not earned, all they create is higher prices. And when wage increases are not earned, all they create is higher prices. There was the answer to all my questions. Everything I heard came clearly into focus now. And really, it was simple. But it was something to keep a man thinking. Thinking about wages and prices racing each other higher and higher each year. A race in which nobody wins anything of real benefit. I realized it must end. That we must find the proper balance between what we want today for ourselves and what we want for the future. For our children. Because after all, that future belongs to them. If you would like a free copy of a pamphlet covering the film you have just seen, address a card or letter to the Chamber of Commerce of the United States, Washington 6, D.C. and ask for Everybody Knows. So essentially, uh I was right. Um it was a guess. I hadn't even seen it. Um but it was a guess. Uh and this is where the, you know, free enterprise the the whole thing about, you know, what who makes money and all that stuff comes from this kind of post-war boom uh boom of uh these these films that kind of talk about like, well, you know, America's the greatest system, capitalism is the greatest system. And, you know, contributed to what I think was, and this is me soapboxing, okay? This is my personal opinion. Contributed to where we're at now with this uh salary vast amount of salary CEOs being paid an insane amount of money um and workers not being paid uh or being paid for their time. And then, you know, when there's movement to say like, "Well, you know what? We need to pay workers more." And it's like, "Well, we're not making enough money. So, the the shareholders will be upset. Blah, blah, blah, blah." And it's like, you know, it's it's really frustrating. Anyways, uh excuse me, but that this is where it comes from. This all of this stuff, these beautifully produced, beautiful color films that talk about how you shouldn't ask for a raise. Uh all right. So, we got something uh on the telecine back here set up. Which way do I go? There's a telecine right there. Um it is a military film and it's uh US Air Force training film. It's declassified and it's super faded red. So, here it is. Refrigeration principles of mechanical refrigeration. You've probably heard the story about the salesman who was so good he could even sell a refrigerator to an Eskimo. It's not true, of course. Eskimos don't need refrigerators. They have nature's own way of keeping their food cold. But in warmer climates, refrigeration is part of our daily lives. We use it to keep ourselves comfortable, to keep our food fresh, and our beverages cold. You might say that a refrigerator works by taking heat on the inside of the box and getting rid of it on the outside. Refrigeration is the transfer of heat from a place where it is not wanted to a place where it is unobjectionable. To do this, a refrigerator uses a unit inside the box that takes up heat and a unit outside the box that gets rid of it. These units are called the evaporator and the condenser. They are tied together by connecting lines referred to as the suction line and the liquid line. Also in the system are the compressor, which is a pump, the expansion valve, and in many systems, the receiver, a kind of storage tank. A chemical substance called the refrigerant flows through the system. It's the refrigerant that picks up BTUs of heat from inside the box and discards them outside. In the process, the refrigerant changes from a liquid to a gas. Then, in the condenser, it changes back to a liquid. At the same time, the pressure increases in the compressor and decreases in the expansion valve. Before you can understand how the system works, you must learn why and how these changes take place. That means learning some basic principles concerning heat. To begin with, take a swimming pool and Cathy, who was swimming in the cold water. After she has dried off, she finds the air warm. But Helen has just come from the steam room, and she thinks the air is cold. The words hot and cold are relative. They are used to compare one thing to another. As the girls gossip together, Cathy gets warmer. Heat from the air passes to her body and warms her. But Helen gets cooler. Heat passes from her body to the air. Heat always passes from a warmer substance to a cooler one. If you put an ice cube into water, the water is cold, but the ice is even colder. By comparison, the water is warm. Heat will flow from the water to the ice. This changes the ice, which is a solid, to water, which is a liquid. If you heat the water, it turns into a vapor. This vapor is a gas. These three, solid, liquid, and gas, are called the three states of matter. All matter around us exists in one of these three states. Now, let's see what happens to temperature if you apply heat to the ice. The thermometer reads 32° Fahrenheit. As the ice changes to water, the temperature stays constant at 32°. The heat is causing the change of state from solid to liquid. Then, as you continue to heat the water, the temperature increases until it reaches 212°. The water starts to boil. The temperature remains at 212°. Heat from the flame is now being used, not for a change of temperature, but for the change of state. Remember, heat is taken in for the change from solid to liquid. Heat is taken in for the change from liquid to gas. Now, a change of state is always accompanied by a gain or loss of heat. This is a very important point. Any substance takes in heat when it boils or changes from a liquid to a gas. And any substance gives off heat when it condenses or changes from a gas to a liquid. Here's a container filled with gas. We add a thermometer to measure the temperature of the gas and a pressure gauge to measure its pressure. What happens if you push in on the piston? Answer, the pressure increases and the temperature increases. Now, let the piston out. The pressure goes down and the temperature goes down. The rule is, when a gas is compressed, the pressure goes up and the temperature goes up. When a gas is allowed to expand, the pressure goes down and the temperature goes down. It's true for any gas. Now, let's see how a refrigerator works. We'll begin at the receiver where the excess refrigerant is stored. It is in the liquid state and under high pressure. The high pressure forces the refrigerant through the liquid line to the expansion valve. This valve causes a pressure drop. The high pressure liquid becomes a low pressure liquid. This is like letting air slowly out of a balloon. The air in the balloon is still under high pressure, but the air that gets through expands and its pressure drops. In the same way, refrigerant that passes through the expansion valve expands and its pressure drops. The low pressure refrigerant flows into the evaporator. Now, if any of the food in the box is warmer than the refrigerant, heat will flow from the food to the evaporator. So, in the evaporator, the refrigerant takes in heat and begins to boil. Remember, any substance takes in heat when it changes from a liquid to a gas. The gas is sucked through the connecting line into the compressor. As the piston moves down, the suction valve opens. The gas is sucked into the compressor. As the piston starts up again, the suction valve is forced shut and the discharge valve is pushed open. On this stroke, the gas is compressed. Remember what happens when gas is compressed? Pressure goes up, temperature goes up. The gas, now at high pressure and high temperature, flows into the condenser. The gas is hot, hotter than the surrounding air, so it gives up heat to the air. As the refrigerant loses heat, it starts changing back into a liquid. To complete the cycle, the liquid refrigerant returns to the receiver. Now, let's review the whole thing. Refrigerant under high pressure flows from the receiver to the expansion valve. The valve causes a pressure drop. The evaporator takes in heat from the box. If anything in the box is hotter than the refrigerant, it gives up its heat to the refrigerant. As the refrigerant takes in heat, it changes from a liquid to a gas. Remember, any substance must take in heat in order to change from a liquid to a gas. The compressor sucks the vapor out of the evaporator and compresses it. This increases the pressure and temperature. The vapor is now hotter than the surrounding air. So, in the condenser, heat is given off to the air. As the refrigerant loses its heat, it changes from a gas to a liquid and flows into the receiver. Now, let's consider some additional points that many refrigeration students have trouble understanding. In the evaporator, the temperature may be very low, perhaps 21° below zero. And yet, the refrigerant is boiling. How can anything boil at such a low temperature? Water boils at 212°. But, other substances boil at other temperatures, some higher than water, some lower. The refrigerant known as R12 boils at -21°. There's no mystery about it. It's simply a property of the substance. The refrigerant in the suction line is carrying all the heat it picked up in the box. But, its temperature is only about 5° above zero. If you touch the line, it feels cold. How can something that's cold be carrying a lot of heat? Remember, hot and cold are relative terms. You know, when water boils, it's very hot. But, refrigerant boils at a much lower temperature. So, the refrigerant can take on heat, change to a gas, and still seem cold. Again, the reason is because the two substances have different boiling points. You have seen the basic principles of refrigeration. Study the system until you understand it thoroughly. Memorizing isn't enough. You must understand what happens and why because all the rest of your work will be based on these same principles. Um fairly dry for a military training film, but also kind of interesting. Um and I What's interesting about it in my mind is the fact that um what they used to kind of keep the interest level high like that's raw like a cartoon of a of a woman in a bikini and then one woman who's like in a towel and um so uh very similar to Mrs. Puff Miss Puff the uh the uh toner commercial which is basically explains using similar animation how xerography works and then they have this shapely uh Miss Puff that shows up in it and she's at the beginning and the end. Um I Oh, I should say that um if you're interested in in uh technology like this and how things like these work um there's an amazing series that came out in the '80s called The Secret Life of Machines And it was made by this uh British sculptor Tim Hunkin, who uh it was a BBC show, and Tim basically would make these sculptures and would use mechanical things to make the sculptures. And so he kind of was also an illustrator and had I think he had like a syndicated cartoon comic about how things worked, and they turned it into a show. And so he's been re-releasing them. Um he's been restoring them, which is questionable, but at least they're they're better quality than what was available before. And so he covers different types of household technologies. And he does one on refrigerators, which is really great. And he does kind of a thing he does all these kind of examples and the one about the sewing machine is also great cuz they have like a a giant sewing machine manned by people. It's It's really really good. And the the other part of this is that I have a film that he did called Why Things Go Wrong, and I reached out to him and I said, "Hey, I can scan this film for you if you'd like to put it online." And he got very excited. And so he's kind of a hero of mine. His his stuff is really really great. So Tim Hunkin, um just look on YouTube Tim Hunkin or Secret Life. Um some really really fun stuff. His stuff about um magnetic tape is phenomenal. He does one about videotape is really really good. I've actually shown it to people trying to who are trying to learn about the mechanics of how videotape works. It is voodoo. All right. Um let's plan for some success. Are you ready? Thanks, Cornett. Aren't you going to high jump this year? Yeah, going to beat Bud Madison's record. What do you think Bud will get in there? That's Bud Jones again out on the track. Yeah. That's my dog. You're not going out for track this year, Bill? Not this year. Well, the team won't seem the same without one of the Madison boys. We've grown used to you and your brother. Excuse me, Miss Evans. I have to run. That'll be all for today. Oh, I'd like to ask Bill Madison to stay for a few minutes after class. Well, I'm glad you could stay, Bill. Come on and sit down. I want to talk with you. I missed your name on the list for the track team, Bill, but Well, your brother used to talk about your practice sessions together. You tried out for high jump last year, didn't you? Yes. Well, Oh, what's the use, Miss Evans? I I like track anyway. Excuse me. Goodbye. I've got to run. I know, Bill. Sit down, Bill. Now, tell me about it. Well, like you said, Bud and I used to practice together at home. We used to practice all the time. Only the practice was for me, not Bud. He was trying to teach me to jump the way he could. Huh. Fine chance I had of doing that. But, Bud was patient. He'd show me how and then let me try again. I tried. I really did. But, it wasn't any use. I wasn't any good at the track meets. Just took up space on the bench. So, why should I go out for the team this year? There wouldn't be a Madison on the team, anyway. Only one of us was good. And you're not that one. You feel that you Well, what shall I say? I'm the failure as as far as track is concerned. Are you on your way home now, Bill? Well, yes. Well, will you walk away with me? I think I might be able to show you something. Why, sure. Sure. What is it? I was just thinking what a poor player that boy is. Who? Um that one, the one with the ball. He's all right. He recovered it. Oh, but he's just not in the same class as the others. Why, he could never get to play on a real team. Just give him a couple of years. After all, he's only a kid. Oh. You mean we shouldn't judge him by the same standards that we use for the others? Of course not. The other boy's bigger than he is. Maybe you have something to learn from him, Bill. I'll say goodbye, Bill. You think it over. Something to learn from him. Why, he's trying the same play again. And he's as sure of himself as if he hadn't just fumbled. He expects to win. Something to learn from him. Well, try again. No, that's no good. Remember how Bud always made that jump? Easy. You'll never be able to jump like that. You're a failure. You mean we shouldn't judge him by the same standards that we use for the others? Wait a minute. 5 ft 6 in. Bud could do that easily. But he had 2 years of practice on me. Why don't I set my standards lower for now? Just start where I am and work up. There. Sure, I can jump that. And in 2 years of practice, who knows? Here we go. Why, that's easy. It's fun now, and I'm doing better. But why I don't understand at all. Well, do you still feel like a failure? No. No, not at all. Well, you feel as though you were succeeding. I sure do. I think you have your answer right there, Bill. When you think you're failing, you go right on failing, or you stop trying, and you begin to worry. And how? Well, it's common enough, Bill. Lots of people actually make themselves ill by planning for failure. But you're not doing that now. No, I'm I'm not. I'm thinking about all the practicing I want to do, and how about in 2 more years? But you might say I'm planning for success. Positive thinking, Bill. When we think that way, we put more effort behind our practicing. Of course, it's about the same whether it's high jumping or anything else. Whatever we plan, we expect things. If we're wise, we expect possible things. Now, suppose we picture your expectations in some situation like this. You're hoping for a lot. But perhaps the situation is such that you can fulfill only this much. There's such a difference between expectation and fulfillment, that you're doomed to failure. And each time you fail, you become more discouraged. But, Miss Evans, I've always been told that I should set my goals high. Yes, Bill. Set your final goals high, but set your present goals within your ability to fulfill. Now, look at it this way. Perhaps this is a reasonable final goal for you. But you can't expect this much today. You may expect to accomplish this much today. Your fulfillment equals your expectation. In 6 months, with hard work, you may be able to expect more and fulfill more. In a year, still more. After some time, you can reasonably set this as your goal and succeed. I gather you've learned that already about your high jumping. Once you set your goals within reason, you began to succeed. And now that you're in the habit of succeeding, you can carefully raise your goals little by little. That's right, but you said that was true of other things besides high jumping. I certainly did. For example? Oh, for example, the student who doesn't really try to do his school work because he can't be perfect. The boy who has a little quarrel with his best girl and then worries and feels he's a social failure. The girl who turns down several date offers and then cries her heart out because the one she wanted to call her didn't. Just think how much happier they could be and how much more successful if they would plan for success. Find out what is possible, make plans which can be successful, and do your best. I think I'll go out for track after all. I may not win anything this year, but I'll be learning, and next year Next year you can plan for higher success, Bill. Yes. Thanks, Miss Evans. Plan for higher success. You just watch me succeed. That's what I plan to do, Bill. Cornett makes it so easy. It's like all you got to do is this. And as Rick Kay is prone to say during a Cornett film is, "Make a list. Make a list, go down the list, and check it off." Um yeah. We know how that works, but uh it's like Miss Evans, get out of my life. Leave me alone. Um yeah. I love I love Cornett. The The universe that is Cornett and how how things work in the Cornett world pretty great. Um what do we want to watch? Let me see how long this one is. 16 minutes. Uh this one I don't know how long this is. Gee, Skip, if you only prepared Okay, this one is we're back to science again, and uh maybe this will help explain some of the questions you have about refrigeration. A refrigeration film. This is the nature of heat. Heat, enough to melt steel. Cold, enough to freeze a gas into a solid block. Explosions generating temperatures running to millions of degrees, hotter than the sun itself. These are some aspects of our modern knowledge of heat and its transfer. The modern study of heat begins with Count Rumford in 1798. His studies on the boring of cannon led to the knowledge that the mechanical energy of a turning drill is transformed through friction into heat. And that heat is thus another form of energy. Here, if we touch a bit of phosphorus to the metal, we see that enough heat has been produced to ignite the phosphorus. To understand this, we need to think of all matter as made up of moving particles called molecules. The more heat these molecules acquire, the faster they move. Thus, heat is the energy of the motion of molecules. Heat is transferred by three methods, conduction, convection, and radiation. Heat in the metal plate is transferred to the phosphorus to set it ablaze at one end of a wire. The heated faster moving molecules at this end of the wire pass their motion or their heat to nearby molecules. Thus, heat is transferred along the wire. In another experiment, we can see how heat from the flame of the burner is transferred along a wire passing from molecule to molecule to melt a ball of wax. This process is called conduction. We can compare how readily various materials conduct heat by fitting them with thermometers. Our test materials are copper, glass, wood, and no material at all or a vacuum. All the thermometers read 29° C at the start of the experiment. The bottom of each test material will receive the same amount of concentrated heat. 30 minutes later, when we compare the thermometer readings, what can we learn? Copper and metals in general conducts heat very readily. The top of the copper block is quite hot. Glass and earth materials conduct heat only moderately well. Wood, like other vegetable and animal fibers, conducts very little heat. And the vacuum in the light bulb conducts even less heat. A perfect vacuum would conduct no heat at all. There are large and important variations in the capacity of various materials to conduct heat. When we make the same test with various building materials, we find that glass is a fairly efficient conductor of heat. Brick conducts nearly as well. Plaster is less efficient as a heat conductor. And fiberboard is the least efficient. Understanding the different rates at which various materials conduct heat, can you explain some of their practical uses? Let's remember that heat is the energy of the motion of molecules. Solid materials conduct heat by passing increased motion along from molecule to molecule. Do liquids and gases also conduct heat? Here is a beaker of water with ice floating on top. A second beaker contains a barrier of steel wool, itself an excellent conductor of heat, and also some ice. We apply heat to the bottoms of both beakers. By speeding up the action in the camera, we can see that heat is readily conveyed to the top of one beaker, but much less rapidly in the second. How can we explain this difference? Let's refer again to the molecular theory of matter. Liquids, too, are made up of molecules in motion. But here, they circulate freely within the container. Now, what happens if we heat some of these molecules? The heated molecules move faster. They tend to spread apart. The heated water expands, making this part of the water less dense than the rest. It rises, and heavier, cooler water comes in contact with the source of heat to be warmed and expanded. So, a current is set up within the liquid. This process of heat transfer is called convection, since heated material is convected or conveyed from one place to another. Adding visible particles to the water, we can see the convection currents as they distribute heat through the liquid. But here, the convection currents are turned aside by the barrier of steel wool, and less heat reaches the top of the beaker. In liquids and gases, it is convection currents, rather than conduction, which transfers the heat. Understanding the convection of heat, can you explain why a chimney on an outdoor fireplace helps create a draft for the fire? Can you explain the workings of this type of hot water heater and its storage tank? Do you understand why a frozen food cabinet can be left open at the top? Liquids and gases transfer heat by convection. Rapidly moving molecules cause the heated portions of a fluid to expand and rise, setting up convection currents. How does heat reach us from the sun, traveling through empty space? It travels as radiation, which we can easily focus with a lens, and so build up intense heat. But can we distinguish between visible light and radiated heat? Using the same lamp and lens, but placing over the lens a filter which absorbs almost all the visible light, we find that there is no apparent sign of radiation reaching the paper. Yet enough invisible heat radiation reaches the paper to ignite it. Using the same lens, we can focus radiation from an electric iron on the bulb of a thermometer and see that all warm bodies radiate heat. Heat travels by radiation. Radiant heat, like the radiations we see as light, can be focused. It can be reflected. Certain materials, like glass, allow radiant heat to pass through. Others, like plants and the earth, absorb it and are warmed by it. In a radiant heated room, how is it possible to feel comfortably warm while the temperature of the air remains invigoratingly cool? We have seen that heat is the energy of the motion of molecules. It is transferred from place to place by three methods: conduction, convection, and radiation. From the beginnings made by Count Rumford, we have developed our knowledge of the nature of heat and its transfer to help solve our practical problems of the control and use of heat. How can the tremendous quantities of heat generated by changes within the nuclei of atoms be controlled and put to practical use. Fascinating. I think about how many films begin and end with an atomic bomb blast. Um it's very comparable to I was watching been going through and watching Colombo episodes. Um and so the uh the great thing is there there was this one it was about this guy who did Robert Culp play this kind of uh motivational research person and he made these commercials or promotional films and he did a promotional film about sales. And it ends with um the Apollo taking off and then I think about oh yeah like how many films do I have that actually end they have nothing to do with space program. But they're talking about society about technology and society and how great America is and it it ends with you know a moon launch. That's how great we are. So I'm not going to leave you with an atomic blast as your last image. Here's some assorted uh canned food commercials. Campbell's new new Noodle O's soups. New new noodle soups that kids will come running for with oodles and boodles of circular noodles. Spoonable, unspillable, non-skid noodles. So, there's never a slip 'twixt the bowl and the lip. First, there's Campbell's Chicken Noodle O's soup. Chicken in a bright, full-flavored broth with lots of little noodles in the round. Mm good. Then, there's Campbell's Tomato Beef Noodle O's soup. Good ground beef in a sassy tomato soup with a whole mob of Noodle O's. New new Noodle O's. Old Noodle O's Noodle O's. Noodle O's. Announcing an amazing new beauty discovery. Bounty complete cooking sauce from Campbell. This one contains everything you need for meatloaf. All you need is the meat. Mix one cup with ground beef, form into a loaf, and bake. Top with the remaining sauce, 5 more minutes in the oven, and you'll serve a beautiful meatloaf every time. Beautiful. Bounty can make you a beautiful cook. New new Noodle O's. Campbell's two new Noodle O's soups. Campbell's Chicken Noodle O's. Tender chicken, golden broth, and lots of noodles in the round. And Campbell's Tomato Beef Noodle O's. Tomatoes, ground beef, and a whole mob of Noodle O's. Both with oodles and boodles of spoonable noodles. Old Noodle O's Noodle O's. Chicken or tomato beef. The early visitors to our land learned about beans from the Indians, and before long You try. started adding delicious touches of their own. Very nice. But, don't you think it could use a little molasses and maybe brown sugar? Now that was flavor. Not bad. To get that same flavor today, try Campbell's old-fashioned beans in molasses and brown sugar sauce, developed from an authentic colonial recipe. What's the meaning of this? We want a good lunch or it's mutiny. Aye. Captain! Did you hear that? Daddy, Mr. John, I have a hunch. Franco-American spaghetti for lunch. If kids ran the world, lunch would always be Franco-American spaghetti. It has the special mild tomato sauce only Franco-American knows how to make. And you can get it with nutritious ground beef. Beef in every bite. Or with six beefy meatballs, all with a mild sauce so good kids never get tired of it. The sauce is boss. A shipshape lunch. If kids ran the world, lunch would always be Franco-American spaghetti. What a hunch. The lunch that never fails. This is how it starts. Something happens to upset you. Something happens to make you tense up, cause nerves to snap. And with each mounting pressure, excess acid may start to flow in your stomach. First a drop. Then another. And another. Result, acid indigestion, heartburn, that burning sensation. That's why wherever you go, always carry Rolaids, one of the most effective medications known for acid relief. Only Rolaids contains this exclusive buffering compound. Rolaids breaks into thousands of tiny particles. Each particle consumes 47 times its weight in excess stomach acid. Helps control the steady acid flow. So, always carry Rolaids for fast, long-lasting relief. Handy, convenient Rolaids consumes 47 times its weight in excess stomach acid. Rolaids. Campbell's new new Noodle-Os. Noodle-Os soup that Sorry about that. Uh anyways, um there's some delicious canned uh food for your lunch. Uh Noodle-Os being the SpaghettiOs um competitor that actually uh I think uh Campbell's actually owns Franco-American now, so all the canned uh circular things are owned by the same people now. Um but I hope you had a a good show. I appreciate you joining us. Um as always, you're welcome to uh buy us some coffee. Um now that we're back in the archive, um caffeine is really great uh to help us percolate. Um also, tell the world that you like AV Geeks by hitting the like or subscribe or ringing the bell notification bell, which is something people talk about. Um comment and share. All those things are uh pretty great ways to say to the robots that run all these things um that you know, we like AV Geeks. We like what this good guy is doing. So, um everybody have a great rest of your day, and we'll be back tomorrow. Um please rewind and love each other and that is yourself included. Love yourself. And we will talk again tomorrow. Everybody take care. 8 7 6 5 4 3 8 7 6 5 4 3 8 7 6 5 4 3 8 7 6 5 4 3 8 7 6 5 4 3