Why does it fail?

Discussion in 'Science' started by HereWeGoAgain, Dec 4, 2019.

  1. perdidochas

    perdidochas Well-Known Member

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    Ice is the most common
     
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  2. yguy

    yguy Well-Known Member

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    Way too easy. Those units are made to transfer heat from one side to the other, and they'll do that anywhere in a house that you put them; but if you put one in the middle of your living room, all the heat that gets sucked out of the room by the evaporator will just get dumped back into the room by the condenser.
     
  3. Monash

    Monash Well-Known Member

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    Newtons laws of motion have not been 'debunked' as you seem to claim. They are still perfectly good at their defined role calculating the trajectory and momentum of bodies in motion at low velocities. And they are still applied for this purpose.What they were not designed are the complexities of relativity which subsumes newtons laws when defining things like the curvature of space/time, the properties of singularities and/or motion at or near the speed of light - none of which were were known at Newtons time. Likewise Relativity breaks down when trying to explain gravity at the quantum level and physics inside singularities. It to is regarded as an incomplete theory.

    Despite this no serious scientist would argue that Einstein has been 'debunked'. Within its limitations it is simply too useful and accurate to discard. Same thing with Newtons laws of motion - not debunked just incomplete but useful. In fact there is currently no complete theory of physics which unites all known physical forces and principals in one unified whole.
     
    Last edited: Dec 14, 2019
  4. william kurps

    william kurps Banned

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    We are talking gravity here..
    https://www.google.com/amp/s/www.nbcnews.com/mach/amp/ncna1038671
     
    Last edited: Dec 14, 2019
  5. Monash

    Monash Well-Known Member

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    So was I. Newtons laws allowed for the orbits of planets and satellites to be accurately charted by allowing for the influence of gravity on their motion. Einstein then went on to show that gravity warps space and time in a manner not previously understood. Neither in and of themselves fully explained the origin of gravitational force. Neither do they integrate it with the other known physical forces. They both expanded upon our knowledge of the effects of gravity however and produced useful predictions as a result.
     
  6. Bowerbird

    Bowerbird Well-Known Member

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    You have been watching the ABC :evileye: :p

    https://www.abc.net.au/news/science...-lying-to-our-children-about-physics/11789858
     
    Last edited: Dec 15, 2019
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  7. An Taibhse

    An Taibhse Well-Known Member

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    One of the best videos I seen regarding Einstein’s was staged earlier this year, hosted by Brian Greene, a String Theorist, on a PBS special that makes both the man and the evolution and genesis of his work easier to understand... and why many hold him in reverence. It is laced with humor and human insight.
     
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  8. Bowerbird

    Bowerbird Well-Known Member

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    Catch up with Dr Karl here. He won an igNobel prize for the research he did to get kids involved with science - it was on bellybutton lint :p.
     
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  9. Monash

    Monash Well-Known Member

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    Saw it but didn't read it. Point is both men made huge contributions to physics. The fact that subsequent generations are discovering 'new physics' using tools and observations neither man had access to is hardly a reason to denigrate the insights they did have. We simply wouldn't be where we are now without them.
     
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  10. politicalcenter

    politicalcenter Well-Known Member

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    I personally think that kids should be taught the basic physics first. Like where a fulcrum should be placed to move an object and how to solve real problems in the real world. For the average child and most adults string theory is useless and pointless. Let's not get the horse before the cart. Teach the basics first because Euclidean geometry may be wrong when figuring bent space it still serves us well. Teach the basic math first because Einstein never built a house.
     
    Last edited: Dec 16, 2019
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  11. WillReadmore

    WillReadmore Well-Known Member

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    Plus, work is being done, so the unit will add to the heat of the room. And, if it is evaporation based it will add moisture to the air, making it feel hotter, too.
     
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  12. WillReadmore

    WillReadmore Well-Known Member

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  13. HereWeGoAgain

    HereWeGoAgain Banned

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    Gravity acts just like a magnetic field, between any two objects with mass.

    Why does it fail?
     
  14. HereWeGoAgain

    HereWeGoAgain Banned

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    It is often said that everything is relative.

    Why does it fail?
     
  15. HereWeGoAgain

    HereWeGoAgain Banned

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    1) x = y = 1 [x is defined to be equal to y and both are defined to be equal to 1]
    Therefore
    2) x^2 = y^2
    3) x^2 -1 = y^2 - 1
    4) x^2 -1 = (y- 1)(y+1)
    Since x = y = 1, the following is true
    5) x^2 - 1 = y - 1
    So equation 4 reduces to
    7) 1 = y+1
    Since y = 1 we get
    8) 1 = 2
     
  16. WillReadmore

    WillReadmore Well-Known Member

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    Assuming you mean why is that first sentence wrong ...

    Magnetic fields act on a mass based on factors such as the composition and magnetic properties of the mass, while gravity works on mass.

    In fact, a magnetic field can repulse a mass.

    Also, as the distance between the two objects increases, magnetic attraction/repulsion decreases FAR faster than does gravity. Think about what it would take for the Sun and Earth to have magnetic fields powerful enough to affect our orbit.
     
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  17. HereWeGoAgain

    HereWeGoAgain Banned

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    What is required in order to make heat flow from cold to hot?
     
  18. HereWeGoAgain

    HereWeGoAgain Banned

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    You are still missing a key distinction, but you touched on it.
     
    Last edited: Dec 16, 2019
  19. HereWeGoAgain

    HereWeGoAgain Banned

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    Specifically, Newtonian Physics is valid where we have weak gravity fields and speeds much, much less than the speed of light.

    Relativity mathematically reduces to Newtonian mechanics where the above conditions are true. That is to say that that Newton's Laws are accurate to a large number of decimal places. And the equations from Relativity reduce to the equations from Newtonian Mechanics.

    In a similar vein, the equations from Quantum Mechanics reduce to classical physics for very large numbers of particles and at large scale.
     
    Last edited: Dec 16, 2019
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  20. WillReadmore

    WillReadmore Well-Known Member

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    Well, gravity doesn't "act just like" if one actually means that the mechanism is the same, as gravity is a warping and magnetic fields are not.
     
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  21. HereWeGoAgain

    HereWeGoAgain Banned

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    Well, you've been dancing all around it so I spit it out. There are no magnetic monopoles. All magnets have opposite poles. Gravity is always an attractive force between masses.

    The reason the strength of a magnetic fields falls off faster with distance than does gravity, is because there are two poles and not one.
     
    Last edited: Dec 16, 2019
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  22. WillReadmore

    WillReadmore Well-Known Member

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    Better answer! I thought I more or less had that covered by just saying that a magnetic field may repulse while a gravitational field can not. But, saying why is obviously better.
     
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  23. Monash

    Monash Well-Known Member

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    Pretty much what I tied to say in an earlier post but expressed much more eloquently.
     
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  24. Monash

    Monash Well-Known Member

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    :smile: The question is posited around a false concept of what the terms 'hot' and 'cold' actually define.

    Any object that is 'cold' by default contains less thermal energy and is in a lower energy state than the surrounding environment. Likewise a 'hot' object holds more energy and is at a higher energy state that its local environment. By definition cold is therefore the relative absence of heat.

    The laws of thermodynamics make it clear that energy (like water) runs downhill, not up. So in theory the only way to extract heat from the cold object and transfer it to a hotter one would be to put the cold object in a even colder freezer (heat exchanger) thereby lowering its temperature even more while at the same transferring the heat you have removed across into the 'hot' object. A process BTW that would not only be extremely inefficient because heat would be lost at every stage of the process. This is because neither the freezer, heater or the transfer mechanism can ever be 100% effective - again according to the laws of thermodynamics (spoil sports :steamed: ) but also because the freezer and heater would have to have an external power source to run.

    P.S there might be some experiments in QM where the effect described could perhaps be observed but any such effect would transient and minute in scale - and most definitely not applicable to any real world purpose.
     
    Last edited: Dec 17, 2019
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  25. HereWeGoAgain

    HereWeGoAgain Banned

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    Bingo!
    In order to make heat flow from cold to hot, you have to do work on the system.

    Air conditioners make heat flow from cold to hot. .
     
    Last edited: Dec 17, 2019

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