Why We Can't Invent a Perfect Engine: Crash Course Engineering #10
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Date: 2022-04-04
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Comments and reviews: 10
Mikayla
The way I see it, the 2nd law isn't _fundamentally_ about energy at all. Rather, it's all about probability. It's not that we _can't_ make a perfectly efficient engine, it's just the the probability of it happening is practically 0, but actually slightly higher. What's really going on is that entropy is a measure of the number of states a system can exist in. We talk about macrostates vs microstates. For example, if our system consists of a single vase, one potential macrostate would be -broken-. A microstates is an exact configuration of particles. There are FAR, FAR more microstates that correspond to -broken vase- than -not broken vase-, so a system consisting of a broken vase has higher entropy than one consistenting of a whole vase. This is where the misleading description of entropy as being a measure of -disorder- comes from. Most macrostates we'd consider disordered are higher entropy simple because there are more microstates that correspond to them. But this isn't what entropy is about. So what does this have to do with energy and efficiency? Well anytime we apply energy to a system to do work on it, we're changing the state of the system. Even if we intentionally apply the energy in a very specific manner, there are simply SO MANY ways for some of the energy to be wasted compared to the number of ways for it to all be used for useful work. There's nothing _stopping_ a 100% efficient heat engine from existing, per se, but the probability of it even a single perfectly efficient heat engine cycle to occur is such that we'd never expect it to happen in any way imaginable amount of time. _However, _ given infinite time, it's virtually _guarenteed_ to happen, not just once, but an infinite number of time. That's because _anything_ with a non-zero probability of occuring, no matter how tiny, will eventually occur given a sufficiently long period of time. However, the probability is such a thing is probably on par with the probability of all the particles in your body quantum tunneling at the exactly the same time in such a manner to teleport you someplace. It theoretically _could_ happen, but don't count on it. I think the amount time needed for it to have even a 50% chance of occuring is longer than the age of the universe, though I'm going on memory.
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The way I see it, the 2nd law isn't _fundamentally_ about energy at all. Rather, it's all about probability. It's not that we _can't_ make a perfectly efficient engine, it's just the the probability of it happening is practically 0, but actually slightly higher. What's really going on is that entropy is a measure of the number of states a system can exist in. We talk about macrostates vs microstates. For example, if our system consists of a single vase, one potential macrostate would be -broken-. A microstates is an exact configuration of particles. There are FAR, FAR more microstates that correspond to -broken vase- than -not broken vase-, so a system consisting of a broken vase has higher entropy than one consistenting of a whole vase. This is where the misleading description of entropy as being a measure of -disorder- comes from. Most macrostates we'd consider disordered are higher entropy simple because there are more microstates that correspond to them. But this isn't what entropy is about. So what does this have to do with energy and efficiency? Well anytime we apply energy to a system to do work on it, we're changing the state of the system. Even if we intentionally apply the energy in a very specific manner, there are simply SO MANY ways for some of the energy to be wasted compared to the number of ways for it to all be used for useful work. There's nothing _stopping_ a 100% efficient heat engine from existing, per se, but the probability of it even a single perfectly efficient heat engine cycle to occur is such that we'd never expect it to happen in any way imaginable amount of time. _However, _ given infinite time, it's virtually _guarenteed_ to happen, not just once, but an infinite number of time. That's because _anything_ with a non-zero probability of occuring, no matter how tiny, will eventually occur given a sufficiently long period of time. However, the probability is such a thing is probably on par with the probability of all the particles in your body quantum tunneling at the exactly the same time in such a manner to teleport you someplace. It theoretically _could_ happen, but don't count on it. I think the amount time needed for it to have even a 50% chance of occuring is longer than the age of the universe, though I'm going on memory.
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Anil
not perfect but near perfect
sterling engine gives that
we can easily changed water into hydrogen and oxygen and use hho gas for flames and foods cooking so we use some sterling engine and produced electricity and this electricity is used for hydrolysis of water and we collected the hho gas under the water sealed tank or in some balloon of punctured proof polymer bag and used the gas when we have no more sun out their
so all the world wide scientists are required to do something about this formula
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not perfect but near perfect
sterling engine gives that
we can easily changed water into hydrogen and oxygen and use hho gas for flames and foods cooking so we use some sterling engine and produced electricity and this electricity is used for hydrolysis of water and we collected the hho gas under the water sealed tank or in some balloon of punctured proof polymer bag and used the gas when we have no more sun out their
so all the world wide scientists are required to do something about this formula
reply
Dan
You can work and research Thermodynamics following the career of Chemical or Mechanical Engineering. This is an extremely broad field that governs the laws of nature. Therefore the approaches can be extremely different. In CE, it is much more focused on Equilibrium of solutions/mixtures of solids, liquids and gases and different chemicals (which is hardly seen by MEs. In ME it is much more on Heat Cycles.
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You can work and research Thermodynamics following the career of Chemical or Mechanical Engineering. This is an extremely broad field that governs the laws of nature. Therefore the approaches can be extremely different. In CE, it is much more focused on Equilibrium of solutions/mixtures of solids, liquids and gases and different chemicals (which is hardly seen by MEs. In ME it is much more on Heat Cycles.
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Aerospace
I am an aerospace engineer and I have been mocked by these -physicists- for being an end-user of their theories and equations. Guess what! -
Sadi Carnot, the father of Thermodynamics, was actually a mechanical engineer. On behalf of all mechanical and aerospace engineers in the world: -
IN YOUR FACE Sheldon Cooper!
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I am an aerospace engineer and I have been mocked by these -physicists- for being an end-user of their theories and equations. Guess what! -
Sadi Carnot, the father of Thermodynamics, was actually a mechanical engineer. On behalf of all mechanical and aerospace engineers in the world: -
IN YOUR FACE Sheldon Cooper!
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TheHolyDarkness
:: hypnotically stares at the brown lady-nerd with the British accent and forgets the topic: :
Huh? Wut? Oh, right. In other words we're dying. Yep.
.
There are still joys in life though. :)
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:: hypnotically stares at the brown lady-nerd with the British accent and forgets the topic: :
Huh? Wut? Oh, right. In other words we're dying. Yep.
.
There are still joys in life though. :)
reply
docsaq
If only static nature or increase in entropy and randomness is believed how did chemical materials went to become less and less random in the form of creation of life and evolution. just wondering
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If only static nature or increase in entropy and randomness is believed how did chemical materials went to become less and less random in the form of creation of life and evolution. just wondering
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Mahmoud
Thank you
this video helped me a lot and explained things that i didn't understand before and i watched it more than once in different time to remember or understand things
Thanks a lot
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Thank you
this video helped me a lot and explained things that i didn't understand before and i watched it more than once in different time to remember or understand things
Thanks a lot
reply
oldcowbb
i hate calling entropy disorder, it's very Bayesian. Also, saying that the entropy of the universe always increase is assuming the universe is a isolated system, which we don't really know.
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i hate calling entropy disorder, it's very Bayesian. Also, saying that the entropy of the universe always increase is assuming the universe is a isolated system, which we don't really know.
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Conner
There should be another rectangle at the end of the episode that says -Want to know what an Existential Crisis is click here- and the CC Philosophy episode is hyperlinked.
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There should be another rectangle at the end of the episode that says -Want to know what an Existential Crisis is click here- and the CC Philosophy episode is hyperlinked.
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Peter
2: 15 Why do people say nickleback is useless? Like I've been called a nickleback fan as an insult after saying I like rock. Is that band really that bad?
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2: 15 Why do people say nickleback is useless? Like I've been called a nickleback fan as an insult after saying I like rock. Is that band really that bad?
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