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Does Warm Water weigh more?

  1. Apr 12, 2004 #1
    i read that a stretched spring weighs more than a coiled spring becuase energy increase weight (e=mc2)

    so, does warm water weigh more than cool water? assuming of course it is equal volume and none of the warm water has evaporated?
    does it weigh more becuase it was more energy?
     
  2. jcsd
  3. Apr 12, 2004 #2

    Njorl

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    First, for simplicity's sake, I'll assume none of the water in question is near the freezing point. Water acts real funny there.

    For equal volumes, the warm water would weigh less. The effects of thermal expansion are orders of magnitude higher than the relativistic effects.

    Njorl
     
  4. Apr 12, 2004 #3
    Relativistic mass changes seen in temperature changes

    Given an equal number of molecules, warm water should weigh more since warmth in water is the average speed of the "random" motion of the water molecules and per special relativity any acceleration away from rest and toward the speed of light increases mass.

    By volume, however, water (at sea level atmospheric pressure) is most massive at 4 degrees Celsius. Below that temperature, mass decreases by volume because of the formation of ice crystals. Above that temperature, mass also decreases by volume, but this time because of the spreading out of the molecules caused by their increased "random" kinetic energy (thermal expansion, as Njorl already explained).

    Regarding the stretched spring, it might be thought of as not an equal volume to a compressed spring (ignoring the space inside it and between turns). Therefore we can think of it as taking up much greater volume when stretched, so, again, for it to have gained some type of mass ratio we would be limited to saying it gains mass when stretched only as a function of the number of atoms or molecules that make up the spring (and not as a function of its volume).
     
    Last edited: Apr 12, 2004
  5. Apr 12, 2004 #4
    thanks for a great reply hitssquad.
    i should have said molecules not volume, i was complicating things by saying volume.
     
  6. Apr 12, 2004 #5
    Sorry. I made a mistake in the third sentence of the second paragraph. I said, "Above that temperature, mass increases...." It should say, "Above that temperature, mass decreases...."

    I'll change it from in to de in the post.
     
  7. Apr 12, 2004 #6

    Integral

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    It seems that to claim a change in rest mass due to relativistic effects is an arguable topic. Perhaps it would be better to hedge ones bets on this question. The velocities of any given molecule are <<c therefore any change is far to small to be measured. In physics any claims which cannot be backed up with measurements must be carefully considered. It would be best to say that there is no measurable change, leave it at that.
     
  8. Apr 12, 2004 #7
    Statistical powers vs. arbitrary laws of physics

    Whether something can be measured in a given instance is simply a function of the statistical power employed in that instance. There is no such thing as any given class of things being intrinsically unmeasurable.



    How or from where was this law of physics derived?
     
    Last edited: Apr 12, 2004
  9. Apr 12, 2004 #8

    Integral

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    HUP?

    This is not a Law of physics it IS PHYSICS. If you cannot back up your claims with experiment all you have is claims. Why do you suppose it is that string theory is still a arguable topic. If you don' think it is just talk to a LQG proponent.

    PHYSICS MUST BE BACKED UP BY MEASUREMENT.

    The nature of relativistic mass increase is a not a closed issue, it depends on who you talk to. Meanwhile, it is clear that if mass does increase it is a relativistic effect, now do you want to claim that the molecular speed of water molecules is relativistic? If you do then I will refer you to Thermodynamics where you will find the tools to compute an average velocity. I am not a betting man, but I would but money on the velocities being non relativistic. At these speeds you will find Relativity itself will tell you the effects are unmeasurable and therefore insignificant.
     
  10. Apr 13, 2004 #9
    The meaning of unmeasurability and the speed of pseudorandom motion

    The Heisenberg Uncertainty Principle does not claim unmeasurability of anything. It claims absence of absolute discreteness of measurement.



    From the point of view of a statistical worldview, relativisticness (the quality of being subject to relativistic warping) of speed is itself relative. Whether a given speed range is relativistic is dependent upon measurability of relativistic effects which itself depends solely upon the statistical power in a given instance of measurement. There is no such thing as any given class of things being intrinsically unmeasurable.



    From the point of view of a statistical worldview, there is no such thing as a velocity that is intrinsically nonrelativistic and there is no such thing as a relativistic effect that is intrinsically unmeasurable.
     
  11. Apr 13, 2004 #10

    Integral

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    Lots o' big words in there, Seems you are repeating yourself.

    You need to iterpret this for me.

    And this.
    Basicly you are thowing out lots of words. until you can trim the fat and say what you mean I am going to stick with my words.


    FACT: Realativistic mass increase is a debated topic.
    You are thowing lots of word that have little content. Would you like to get back to the topic of the thread?

    LOL! I just noticed! Are you really in Corvallis??? Perhaps we should meet at the Beanery,.. discuss this face to face!
     
    Last edited: Apr 13, 2004
  12. Apr 13, 2004 #11
    I prefer First Alternative to Allan Bros., if you don't mind. In addition to its indoor eating space, First Alternative just added a second-story eating deck which you can see to the upper-right in this picture.
     
  13. Apr 13, 2004 #12

    Integral

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    I havn't been in the coop since the latest round of remodel was completed. When I first was there I think it still had sand on the floor from the days of being a Sand and Gravel business ~'76.
     
  14. Apr 13, 2004 #13
    Space within Space: Does H2O show a Zero-Point Energy Reliance

    FACT: Realativistic mass increase is a debated topic.
    You are thowing lots of word that have little content. Would you like to get back to the topic of the thread?


    ------------------

    What intriques me about water is how it seems to have 3 different states, may I call them super-states? Gas, Liquid and Solid and really a 4th which eludes classification? The snowflake which seems to demonstrate a type of interaction with "space" as an energy molecule between 'spaces'.

    Our genetic makeup is composed mostly of Oxygen, Hydrogen, Nitrogen, and Carbon - One explosive, and three flammable elements. And yet water too is composed of highly flammable gases!!!! And so we have to drink water to live, and yet we also breathe one of its key components for our very survival - Oxygen.

    Is there a profound and and as yet undiscovered elusive relationship between water with the Zero-Point vacuum flux? My bets are with the yes camp on this one. Possible the bonding shells can be looked at more closely in extreme cold and/or under high atmospheric pressure to confirm or disprove such a position.
     
    Last edited: Apr 13, 2004
  15. Apr 14, 2004 #14

    Integral

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    Yoda.
    What was that about staying on topic?

    Snow flakes are not a mysterious form of water, They are crystals,their general shape is dictated by the molecular structure of water.

    I was once working in a sort or Foundry, my work involved molten zinc, you would be amazed at the incredible microscopic zinc oxide crystals we were able to grow (not something we want to grow, but how to stop them?) They looked like tiny trees with a single vertical stalk, and a hexagonal set of branches at the top. Pretty cool. The fact is crystals grow, Snow flakes are an example of this.
     
  16. Apr 14, 2004 #15
    I'm gonna 'suck up' and agree with Integral on this one, he is placing the point where it belongs, relative to Science, and Science instruction....'provability' (or 'substantiation') is what tells us the Extrinsic truth, Scientific proofs are based upon that notion.....
     
  17. Apr 14, 2004 #16
    ---

    Neat stuff. Crystalline structures are a given in nature aren't they? I dont know but perhaps I should have been more clear. My position is really that somehow the water molecule demonstrates a zero-point energy relationship, especially in the upper atmosphere where (and I should have pointed this out earlier) hailstones form. I used the metaphor of snowflakes as a simple illustration of the possible laws governing 'space within space' relationshiips with molecules.

    My understanding (from watching the weather channel) is that the formation process behind hailstones is not entirely understood. The general theory that I have most widely heard about is that the wind merely sends the water cascading around and eventually given enough time, is able to gather more water which then combines to produce hailstones of varying sizes.

    Is it possible that as yet unseen forces are at play here instead of the conventional explanation?

    Nevertheless, the unique structure of water still amazes me.
     
  18. Apr 14, 2004 #17

    chroot

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    Yoda: please do not post personal theories in the mainstream science forums. Your questions are okay, but your mentioning that "your position is...zero-point energy" is not welcome here.

    - Warren
     
  19. Apr 14, 2004 #18
    Nucleation upon dust particles is the explaination/understanding that works for formation...isn't it?
     
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