Entropy example, Need explanation
Entropy example, Need explanation
(OP)
Hi all,
I had a thermodynamics lecture a few week ago where our lecturer showed a video of an egg falling and smashing into the floor, which was then replayed in reverse showing the egg come back together, he then asked us can anyone explain why that isnt possible... The answers of "because it cant" or "because that dosnt make sence" were not really suffice haha. I know the 2nd law of thermodynamics is involved, but leaving the law aside, what is a good way of explaining this??? Please help!
Thanks
I had a thermodynamics lecture a few week ago where our lecturer showed a video of an egg falling and smashing into the floor, which was then replayed in reverse showing the egg come back together, he then asked us can anyone explain why that isnt possible... The answers of "because it cant" or "because that dosnt make sence" were not really suffice haha. I know the 2nd law of thermodynamics is involved, but leaving the law aside, what is a good way of explaining this??? Please help!
Thanks





RE: Entropy example, Need explanation
RE: Entropy example, Need explanation
RE: Entropy example, Need explanation
RE: Entropy example, Need explanation
Sorry if asking the same question again, its just our lecturer wouldnt even accept the 2nd law as our answer that day, he just smiled and kept saying " but why not?"
RE: Entropy example, Need explanation
2nd law of thermodynamics - "not only can't we get something for nothing, but we always lose in the process."
Good luck,
Latexman
RE: Entropy example, Need explanation
IMHO, the underlying reason for the obvious asymmetry, or irreversibility of all events, whether macro or microscopic, is the impossible (invariant) time arrow reversal.
Am I right?
RE: Entropy example, Need explanation
RE: Entropy example, Need explanation
It appears to me that the impossibility of reverting the time arrow or, if you wish, cause and effect processes, is the irrefutable answer to all those why's.
RE: Entropy example, Need explanation
RE: Entropy example, Need explanation
Best to you,
Goober Dave
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RE: Entropy example, Need explanation
Good luck,
Latexman
RE: Entropy example, Need explanation
RE: Entropy example, Need explanation
I suppose enough work can be done to reassemble the egg and get it back to its original condition, but then, we are back to the philosophy discussion. But the Heisenberg uncertainty law would suggest that it can never go back to the initial condition.
--Mike--
RE: Entropy example, Need explanation
One example is the process of operating an automobile- the gasoline flows from the tank to the fuel injectors, is combusted in the cylinders, exhausted thru the tailpipe, and some heat is lost thru the radiator to the ambient air. As far as the first law is concerned, all those processes can be reversed and maintain conservation of mass and energy; the exhaust gas would get sucked up by the tail pipe flowing from a low pressure zone to a higher pressure zone , heat from the colder ambient air would flow back thur the hotter radiator to the antifreee mixture and into the hotter cylinder,the exhasut gases would from a mixture of gasoline droplets and ambient air in the engine cylinders, and the droplets form a liquid stream back into the gas tank. But, in my limted experience, that never has happened.
RE: Entropy example, Need explanation
RE: Entropy example, Need explanation
You need to think about what entropy really is. Basically, the universe is running down (think of it as a giant watch spring that is slowly unwinding, with no means of rewinding it). The second law of thermodynamics says that whenever energy is exchanged or converted from one form to another, the potential for energy to do work gets less. This really is what entropy is all about. It is a measure of the lack of potential or quality of energy; and once that energy has been exchanged or converted, it cannot revert back to a higher state. Ultimately, everything throughout the entire Universe will end up at the same temperature, so the entropy of the Universe is always increasing.
Reversible adiabatic processes are good enough describing for some practical processes, but there is always some loss of energy (friction) in the real world, even if it is quite small.
Let's replace the egg with a simpler example, say a brick wall. Suppose the brick wall is knocked down - it can be rebuild so that it looks just the same as before but, in mixing the mortar adding the water and moving the bricks the universe has not actually lost any energy (because that cannot be destroyed or created) but the ability of the universe to do useful work with that energy has been ever so slightly diminished.
I've just re-read this and I'm not sure if it helps or not
RE: Entropy example, Need explanation
rmw
RE: Entropy example, Need explanation
We all know the egg Mcmuffin came before the chicken Mcnugget.
RE: Entropy example, Need explanation
rmw
RE: Entropy example, Need explanation