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Topic Review (Newest First)

  • 09-15-2012, 09:02 PM
    JNXMN
    Quote Originally Posted by Andy Schoen View Post
    Certainly, it is not a scientific hypothesis. But it does provide a nice explanation of where energy came from in the first place, if it cannot be created or destroyed. In other words, it didn't come from anywhere.



    That you are. Energy is energy. What purpose does it make to redefine it? A waste of intellectual effort in my humble opinion. James Maxwell had it correct. And thermodynamic law remains the basis of all natural science (at least as long as I will live).

    The only question here is if positive energy existed at T=0, where did it come from? Or if energy was zero at T=0 (the more elegant solution, IMHO), what created the positive/negative energy to begin with?
    another point of view maybe? the first law defines the physic in OUR dimension and at the time concept we understand currently. maybe when the study of physic advance we'll discover more and see thing from different angle?
  • 09-15-2012, 08:27 PM
    timebuilder
    Quote Originally Posted by hvacrmedic View Post
    I borrowed his train and referred to relavity of motion, but I wasn't necessarily referring to any of Einstien's original hypotheses, and don't in general subscribe to his version of relativity. The question here is whether energy can be created from nothing, and that's a question that's outside the realm of physics. It may even be a meaningless question.


    Or, it may be VERY meaningful, yet be beyond our comprehension.

    We might hypothesize, that energy could not have come from what we conceive to be "nothing," but it is really nothing? Did God act as the source for this energy, and in fact, use his energy to create ALL matter and energy? Did he move energy from another dimension of reality?

    At this point, we can stick safely with the understanding that we have here, and trust that there is a far greater understanding that we may never achieve....
  • 09-15-2012, 08:23 PM
    Andy Schoen
    Quote Originally Posted by hvacrmedic View Post
    Speculative.
    Certainly, it is not a scientific hypothesis. But it does provide a nice explanation of where energy came from in the first place, if it cannot be created or destroyed. In other words, it didn't come from anywhere.

    Quote Originally Posted by hvacrmedic View Post
    So the question becomes, where did the absolute energy come from? (Note that this is just another way of asking the same question again).
    That you are. Energy is energy. What purpose does it make to redefine it? A waste of intellectual effort in my humble opinion. James Maxwell had it correct. And thermodynamic law remains the basis of all natural science (at least as long as I will live).

    The only question here is if positive energy existed at T=0, where did it come from? Or if energy was zero at T=0 (the more elegant solution, IMHO), what created the positive/negative energy to begin with?
  • 09-15-2012, 08:05 PM
    hvacrmedic
    Quote Originally Posted by Andy Schoen View Post
    Or perhaps more correctly, the total sum of energy in the universe is zero. http://en.wikipedia.org/wiki/Zero-energy_universe

    No need to figure out where energy came from. And the First Law still applies.
    Speculative. Energy is after all a mathematical concept, as are positive and negative. In any case, from where did the positive and negative energy originate? Suppose we invent a new physics term, "absolute energy", which is defined as the sum of the absolute values of the positive and negative energy components in the universe, or of some arbitrary closed system. What's to prevent us from doing this? So the question becomes, where did the absolute energy come from? (Note that this is just another way of asking the same question again).
  • 09-15-2012, 06:38 PM
    Andy Schoen
    Quote Originally Posted by hvacrmedic View Post
    Maybe energy doesn't exist at all? That would resolve the paradox wouldn't it. If it never was, then it didn't have to be created.
    Or perhaps more correctly, the total sum of energy in the universe is zero. http://en.wikipedia.org/wiki/Zero-energy_universe

    No need to figure out where energy came from. And the First Law still applies.
  • 09-15-2012, 12:23 PM
    JBM1000
    To even measure absolute zero or below takes a transfer of energy be it a crossover of dimensions of the 4th kind or staying inside our tiny barely able to compute reality. "That is one of my better lines of pure B.S. I must admit"!
  • 09-15-2012, 10:57 AM
    hvacrmedic
    Quote Originally Posted by mgenius33 View Post

    Sounds like we are touching on Einstein's theory, and Socrate's statement noted in my signature...

    I borrowed his train and referred to relavity of motion, but I wasn't necessarily referring to any of Einstien's original hypotheses, and don't in general subscribe to his version of relativity. The question here is whether energy can be created from nothing, and that's a question that's outside the realm of physics. It may even be a meaningless question.
  • 09-15-2012, 10:19 AM
    mgenius33
    Quote Originally Posted by hvacrmedic View Post

    Suppose you're stationed by the railroad track and you're watching a train pass by. You have good info that the mass of the train is X kg, and you measure its speed at Y m/s. You calculate it's KE as

    kg(m/s)^2 or XY^2isn't this the formula for Force=ma, KE= 1/2mv^2

    which in this case turns out to be a rather large number. A passenger on the train however measures the speed of the train as exactly 0 m/s. He calculates that the KE of the train is zero. It has no kinetic energy from his frame of reference. It should be obvious then that the KE that you attributed to the train is not an intrinsic property of the train, but rather just a perception, like color, relating to your particular frame of reference.
    Sounds like we are touching on Einstein's theory, and Socrate's statement noted in my signature...
  • 09-15-2012, 10:09 AM
    mgenius33
    Quote Originally Posted by gregscott View Post
    So, can you think of anything that does not require the transfer of heat?
    A form of energy that doesn't require the transfer of heat?
    Potential Energy...
  • 09-14-2012, 11:12 PM
    JNXMN
    it's actually referring to energy, heat is just one form of energy.
  • 09-09-2012, 09:44 AM
    hydra
    My brain hurts! Excellent explanations though.
  • 09-09-2012, 08:42 AM
    Saturatedpsi
    Quote Originally Posted by hvacrmedic View Post
    What does this have to do with hvac anyway?
    Thank you.
  • 09-09-2012, 12:45 AM
    hvacrmedic
    Quote Originally Posted by Greend88 View Post
    I'll throw a loop for you guys. Ask yourself if energy can not be created then how did it become to be? Did the initial energy of the universe just pop out of nothing?
    Maybe energy doesn't exist at all? That would resolve the paradox wouldn't it. If it never was, then it didn't have to be created.

    A perception of a thing is not neccesarily a property of the thing. Take color for instance. If we say that some object is red, then this only means that it reflects red light and absorbs all other visible frequencies of em waves. But...we are hardwired by evolution such that we instinctively think of the color of an object as an intrinsic element of the object itself--something it "has". In reality, color is just something we percieve, and doesn't belong to the object at all, being light of some wavelength emitted from a source external to the object. To complicate matters, the "color" of an object will also change with relative motion to the object (due to the Doppler Effect.) It's no different with energy.

    Suppose you're stationed by the railroad track and you're watching a train pass by. You have good info that the mass of the train is X kg, and you measure its speed at Y m/s. You calculate it's KE as

    kg(m/s)^2 or XY^2

    which in this case turns out to be a rather large number. A passenger on the train however measures the speed of the train as exactly 0 m/s. He calculates that the KE of the train is zero. It has no kinetic energy from his frame of reference. It should be obvious then that the KE that you attributed to the train is not an intrinsic property of the train, but rather just a perception, like color, relating to your particular frame of reference.

    The bottom line is that our mode of thinking is tailored by evolution toward survival, and along with that came an aptitude for engineering, but not so much an ability to understand the true nature of the building blocks that we stack together. Anything beyond the engineering value of our physics is pure philosophy, which should be avoided for the sake of sanity (unless you're only speculating for personal amusement, or maybe for profit). Physics beyond the math is also called metaphysics.

    I apologize for getting carried away with this. I've had this discussion with real physicists many times. The ideas above are not mine, just ideas that I was finally forced to accept.

    What does this have to do with hvac anyway.
  • 09-08-2012, 08:02 PM
    R Mannino
    Quote Originally Posted by Greend88 View Post
    I'll throw a loop for you guys. Ask yourself if energy can not be created then how did it become to be? Did the initial energy of the universe just pop out of nothing?
    The Law of Conservation of Matter and Energy states it can not be created or destroyed............no the mass of the universe is finite and the energy in it is also finite. The Law just proves we can manipulate it.

    A tree on the forest floor releases the same amount of carbon dioxide if it is left to rot or if it is burned in a fire, the Law in action.
  • 09-08-2012, 12:01 PM
    hearthman
    energy is the potential between atoms created by God caused by the polar charge of electrons or the lack thereof. This results in bonds between atoms that, when broken, releases energy to be used to form new compounds. When you burn a molecule of methane, the bonds between the CH4 and oxyen reform into carbon dioxide and water with the evolution of heat and light.
  • 09-08-2012, 11:15 AM
    Greend88
    I'll throw a loop for you guys. Ask yourself if energy can not be created then how did it become to be? Did the initial energy of the universe just pop out of nothing?
  • 09-08-2012, 10:45 AM
    hearthman

    energy conversion

    Take for example your car's brakes. When your car is in motion, there is kinetic energy that must be dissipated to stop. When you apply the brakes, pads contact the rotors or drums creating friction, which causes them to heat up quickly. Air flowing over the brakes cools the brakes thus transferring the heat by convection and the car stops. Now, think about going down a mountain. You keep riding your brakes until they overheat. What happens? You can't stop and make the headlines.

    Back in the '60s, there were a growing number of motor vehicle accidents from brake failures. The cause was traced to hub caps restricting the flow of cooling air and wheels without adequate air slots. Spoked wheels and those with big spaces can move a lot of air thus often improving braking. If you coat the brakes and wheels with mud, you may not be able to stop hard because the mud insulates the brakes keeping them hot instead of allowing cooling. I've had this happen many times when 4 wheeling.

    Now, think about your rotors and drums. It used to be we turned them down on a lathe to extend their life. However, the amount of allowance you have is so marginal it usually is not worth it. Nowadays, the rotor is ususally replaced out of hand. Why? Because you need a minimum mass of metal to absorb heat from the friction of the brakes without distorting the metal, which would break contact causing failure. It takes a critical minimum mass of metal to stop a car.

    Does this help?
  • 09-04-2012, 12:45 PM
    hvacrmedic
    Quote Originally Posted by syndicated View Post
    As far as the reference to a "closed system", since the universe is a closed system, that point is moot, no?
    Yep. I got that one twisted around somehow. Should have been "isolated" system, and stated like this, "The energy content of an isolated system is constant." In this form there's nothing reduntant about the "isolated system". It defines the boundary conditions relevant to the first law. IOW, the energy content of an open system is not constant.

    When stated in the form that I used initially "energy can neither be created nor destroyed", then boundary conditions are immaterial, since this is a general statement about energy. OTOH, it isn't necessarily true in this form, since we do not know it to be true.
  • 09-04-2012, 09:33 AM
    Saturatedpsi
    Quote Originally Posted by gregscott View Post
    Can you give me an example of one of these conversions?
    I'm not a student of thermodynamics. I read some of the laws 30 years ago, didn't fully understand the implications then and don't fully understand them now. But a little of what I remember tells us all matter contains some amount of heat energy (unless it's at "absolute zero" temperature). So there is always the possibility for naturally occurring heat transfer to take place.

    You also noted:

    "..I suspect that the reference in post #7 to conversion of one form of energy to another still requires the transfer of heat, and that the conversion is never 100% efficient because there has to be a transfer of heat; work was done to complete the conversion, energy was lost in the form of heat."

    Once you throw "work" into the equation, the discussion has to take a different direction. Work requires some input, of some form of energy, to produce some result. If you "input" enough heat energy to a piece of combustible material, in an oxygen containing environment, it will "combust", which is a chemical reaction. In that case, I suppose "heat transfer", from a direct heat energy "input", is the explanation for the result.

    If you apply voltage to a resistive heat element, the element gets hot. There wasn't any direct transfer of "heat" energy to the element. The resulting heat was due to something else, explained by some other law of physics. The electrical energy was inputted to the element, some work was done and some heat energy was a by-product. And don't forget, there was a lot of "energy" input somewhere else, in some other form, to generate the electrical energy.

    The Law of Conservation of Energy is telling us there was no "new" energy created. Some other forms of energy were "manipulated" and expended, in a way that resulted in some heat energy being produced.
  • 09-03-2012, 11:56 PM
    gregscott
    Quote Originally Posted by Saturatedpsi View Post
    There is a lot of that going on naturally, but it's not accomplishing much. Most of the good stuff going on is due to conversion of one form of energy to another.
    Can you give me an example of one of these conversions?
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