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That diagram at 1:42 is almost exactly how your house gets electricity (unless your grid is fed by solar or wind). The power plant uses coal, natural gas, oil, nuclear fission or even garbage to create heat in what they show as the boiler. Then just replace that piston with a steam driven turbine that turns a big generator and boom, your house has glorious power.
Which mathematics? There are so many fields. Arithmetic, Algebra, Geometry, Trigonometry, Calculus, Statistics, Set Theory, Topology, Real/Complex Analysis, etc...
Maybe a General Math applicable too all fields... cause every profession needs at least one math field or branch or a few.......and students in secondary schools need all of them in basic....and math majors need all of the branches in advanced. :)
Thanks! The production value is great. However: At 05:00 you say that there is an isothermal process where heat is slowly added, but the animation shows lots of heat (Q_H) escaping. What gives? At 05:04 You say that the isothermal expansion is 1/2 AB. Shouldn't it be the *entire* path AB? At 05:15 you say "the temperature drops whilst the heat stays constant, which also makes the volume expand". Well this is misleading: a temperature drop would cause an isolated system volume to contract. However in a Carnot engine, the system is doing work on the atmosphere, converting internal energy into work, and dropping the temperature. It's best to say that the expansion work drops the temperature, not that a colder temperature causes an expansion. Also, when you keep saying "the heat stays constant", shouldn't you be saying "there is no heat flow" or something equivalent? At 05:40 you say "the heat doesn't change" but perhaps you should be saying that there is no heat flow, or the system is thermally insulated, or something else equivalent. The way you explain it sounds as if heat is a state property, when it's not.
before my summer vacation they were exactly sincronised with what i did at school. in the vacation they we don't do, so it's perfectly sincronized now too :)) helps me a lot, as this year we have a bad teacher
Excellent video on engines! I'm really looking forward toward our next segment of the course: Electricity and Magnetism! Time to explore Electric Potential and Gauss' Law!
I spent an hour this morning reading about thermodynamic engines from a Physics textbook and still had trouble understanding. Then I watch this 10 minute video and immediately understand what's going on.
Compilation Guy>>>> And I need a crash course on basic gymnastics and acrobatics that covers front- and backhandspring, front and back somersault, aerial, side-somersault and handstand.
I'm doing a degree in physics. We have t covered this yet and I find this confusing. I really only think people enjoy watching these videos if they already understand the topic. I don't think that crash course's style is at all suited to physics
pro tip to watching these fast videos: pause between sentences to mimic a realistic conversation and time for your brain to understand what she just said.
The animation of a refrigerator at work is completely reversed and incorrect: after the liquid is turned into a gas it is compressed at which point it flows to the condenser to shed the heat extracted in the fridge(and the heat generated by being compressed) and return to a liquid. This liquid is then sent through an orifice or long, thin capillary tube so that it pressure is reduced hence it's temperature lowered. This liquid then goes to the evaporator inside the fridge where it absorbs heat from the interior and boils into a gas before returning to the compressor. The animation shows the compressor as a "decompressor" or expansion device(orifice, capillary tube) and that is opposite of it's true function as the whole thing is reversed.
Failure is always a option. To say that it isn't one is an illusion. The trick is to avoid failure. If one runs into a failure state, learn from it to increase the chances of success.
A nice recap for those that understand the principles already but far too quick for new comers. Was hoping to use this in a lesson on the Otto cycle but it's above and beyond my year 13 pupils!
Is there a quantity to describe how well a real engine compares to a Carnot engine working across the same temperature range. Like actual efficiency/Carnot efficiency
I found a little bit confusing the explanation about the reason of isothermal processes in carnot cycle.. It's isothermal to favor reversibility?? It does not make too much sense, because the heat transfer is with the hot source and cold sink not within the cycle... I mean there is indeed a temperature difference between the hot source and the hot isothermal process, the only fact that maintain the process isothermal is that it's doing work at the same time that it absorbs heat... Other remark is that the T-s diagram is more apropiate to understand heat engines cycles and it efficiencies (just need to spot the ratio between the area under the cold curve and the area under the hot curve)
I don't think this series has really explained entropy well enough for a T-s diagram to be helpful to anyone hearing about thermodynamics for the first time. As far as reversibility goes, isothermal and adiabatic processes are required, du to the definition of reversibility. Any heat transfer from a high temperature to a lower one produces entropy. A reversible process produces no entropy. If there is no temperature difference during the heat exchange, no entropy is produced, making isothermal processes the only reversible kind of process that allows for heat exchange, while adiabatic processes pass for reversible by not having any heat exchange that can produce entropy.
I don't think this series has really explained entropy well enough for a T-s diagram to be helpful to anyone hearing about thermodynamics for the first time. As far as reversibility goes, isothermal and adiabatic processes are required, du to the definition of reversibility. Any heat transfer from a high temperature to a lower one produces entropy. A reversible process produces no entropy. If there is no temperature difference during the heat exchange, no entropy is produced, making isothermal processes the only reversible kind of process that allows for heat exchange, while adiabatic processes pass for reversible by not having any heat exchange that can produce entropy.
You have stated a contradiction " A reversible process produces no entropy. "; the isothermal process of carnot engine DO produce entropy, you can easly check the T-s diagram or think in terms of dQ = TdS; for heat to be transferred you need to augment the entropy content.
Abraham Vivas Isothermal heat exchange leads to entropy being transferred, but no entropy is produced, in the ideal case. dQ = TdS only deals with entropy transfer in internally reversible processes. I'm not saying the entropy doesn't change in a reversible process, only that no new entropy is produced. Any entropy increase in a Carnot process is brought in with the added heat, and transferred back out again, when the system gets rid of heat.
Only with me or there was an issue with the mic in this video? There is a high-frequency "shhh" in her voice I never heard in any of the videos before o.O
Off topic of the contents of the video ... sound editing seems a bit off, as her 'S' (or soft 'C') are very harsh and cutting, as if that frequency was amplified or something.
Where would electric engines stand? They start off with ambient heat, max torque at 0rpms, output heat is significantly lower than a steam or an IC engine, practically all are reversible. (Edited to fix auto correct errors)
Electric engines convert electromagnetic energy into kinetic energy. It's an entirely different process. In principle, an electric engine is the same as a generator, but used in reverse. If you spin it, it produces an alternating current. If you give it some AC, it will try to spin fast enough to match the frequency of the current.
Can any one help me with this problem my physics teacher wants me to do. Problem) he wants us to remove water from a sealed jar, but we cannot remove lid, put holes in any part of the jar, tilt the jar, and must be done with house hold items, and he said he wanted it done 'now', so i'm assuming i can't just wait for the water to evaporate. ps) the jar is full of water.
LOL! What material is the jar and lid made out of? Also, you say "I can't just wait for the water to evaporate", does that mean the seal lets out water vapour? Then you could heat the water inside.
well I know the water will evaporate, faster if I increase outside temperature, but will all the water evaporate, and wouldn't that be to much pressure for the jar?
That's probably a lot less efficient, since most nuclear plants are basically steam engines hooked up to generators. You wouldn't need an entire cart for fuel (instead, you would probably need several carts filled with cooling water to prevent a nuclear meltdown), but you would use the steam engine to get kinetic energy, to convert to electricity, only to convert it back into kinetic energy. Not that I want to break your steampunk bubble. It's just, if you want a nuclear powered train, skip the conversion into electricity.
A conventional RTG is probably not hot enough, a small fission reactor combined with a cryo cooling system, lot's of heat exchangers and a large water tank, point is that all the coal hassle is gone and a few grams of plutonium is gonna last forever with additional radiation issues i know ;-) A train still needs a lot of electrical power for other functions.
robson668 That's why you connect both the generator and the gear box to the axel coming out of the steam engine. Just make it do double the work. Plutonium should give you the energy you need :) Just don't waste energy and materials by using an electric motor (aka a second generator)
These videos are good overall, but that's just an awful description of how a refrigerator works. She doesn't even mention the pressure difference in the two halves of the loop. Also, all you young'uns with working high-pitch hearing need to learn how to use the equalizer on your computer or phone.
I'm sure someone can figure out how to use Maxwell's Demon for a Carnot engine but I myself can only envision it in a long chain. I'm not sure how many would be needed, I would surmise at least 3 but that doesn't take into account human perception which occurs at ~ .02-.05 secs per frame. It may be a hundred for all I know.
No. A Carnot engine has nothing, directly, to do with Maxwell's demon. It is also important to point to point out that, as of Sept 22, 2016, Maxwell's demon remains a totally imaginary device. It was and is a thought experiment. Even as a thought experiment, it is generally considered that it could not violate the second law of thermodynamics, though the theoretical thinking involved is quite abstract. There have been practical devices built that have some characteristics of a Maxwell's demon, but none of these, either in theory or practice, violate the second law.
I think I should clarify what I mean by a "practical" device that has some characteristics of a Maxwell's demon. By practical, I mean a real device working with real atoms and molecules, not merely a theoretical construct. However, these devices are not practical in a larger sense. They are laboratory research devices. They allow research into interesting physics and chemistry. They will not power your lawnmower.
