Glass

Discussion in 'Computer Support' started by Ctrl¤/Alt¤/Del¤, Aug 11, 2006.

  1. Is glass a solid or a liquid?

    Thanks,

    Alt
    --
    All of Usenet is in a psychological, emotional, and antisocial free fall
    into an abyss and fully immersed in a drowning pool of mental illness.
     
    Ctrl¤/Alt¤/Del¤, Aug 11, 2006
    #1
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  2. Ctrl¤/Alt¤/Del¤

    Oldus Fartus Guest

    Oldus Fartus, Aug 11, 2006
    #2
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  3. Ctrl¤/Alt¤/Del¤, Aug 11, 2006
    #3
  4. Ctrl¤/Alt¤/Del¤

    Oldus Fartus Guest

    Ctrl¤/Alt¤/Del¤ wrote:
    > On Fri, 11 Aug 2006 12:21:16 +0800, Oldus Fartus
    > <> wrote:
    >
    >> Ctrl¤/Alt¤/Del¤ wrote:
    >>> Is glass a solid or a liquid?
    >>>

    >> Good question!
    >>
    >> A couple of good essays are at
    >> http://math.ucr.edu/home/baez/physics/General/Glass/glass.html and
    >> http://dwb.unl.edu/Teacher/NSF/C01/C01Links/www.ualberta.ca/~bderksen/florin.html

    >
    >
    > Thanks, Oldus Fartus, glass is a liquid just as I thought.


    Well, no it isn't according to both those links (but you have to read
    them in their entirety). The general consensus was
    "Glasses are amorphous solids. There is a fundamental structural divide
    between amorphous solids (including glasses) and crystalline solids.
    Structurally, glasses are similar to liquids, but that doesn't mean they
    are liquid. It is possible that the "glass is a liquid" urban legend
    originated with a misreading of a German treatise on glass thermodynamics."

    --
    Cheers
    Oldus Fartus
     
    Oldus Fartus, Aug 11, 2006
    #4
  5. On Fri, 11 Aug 2006 04:04:12 GMT, Ctrl¤/Alt¤/Del¤
    <Ctrl¤/Alt¤/Del¤@cad.com> wrote:

    >Is glass a solid or a liquid?


    Technically, glass is a liquid--the most viscous liquid on Earth.
    _______________________
    Play with fire! Zildjan drum sticks
     
    Michael A. Ball, Aug 11, 2006
    #5
  6. On Fri, 11 Aug 2006 01:12:18 -0400, Michael A. Ball
    <> wrote:

    >On Fri, 11 Aug 2006 04:04:12 GMT, Ctrl¤/Alt¤/Del¤
    ><Ctrl¤/Alt¤/Del¤@cad.com> wrote:
    >
    >>Is glass a solid or a liquid?

    >
    >Technically, glass is a liquid--the most viscous liquid on Earth.


    That is what I was thinking, Michael. I don't really believe that it
    is just an urban legend that glass is a liquid. Oldus Fartus is being
    very helpful, I just think he may be wrong. I mean, glass really has
    no defined melting point. Everyone knows that a true solid has a well
    defined melting point and glass doesn't possess this quality.

    Alt
     
    Ctrl¤/Alt¤/Del¤, Aug 11, 2006
    #6
  7. Ctrl¤/Alt¤/Del¤

    Flyer Guest

    "Oldus Fartus" <> wrote in message
    news:44dc0f6e$0$15974$...
    > Ctrl¤/Alt¤/Del¤ wrote:
    >> On Fri, 11 Aug 2006 12:21:16 +0800, Oldus Fartus
    >> <> wrote:
    >>
    >>> Ctrl¤/Alt¤/Del¤ wrote:
    >>>> Is glass a solid or a liquid?
    >>> Good question!
    >>>
    >>> A couple of good essays are at
    >>> http://math.ucr.edu/home/baez/physics/General/Glass/glass.html and
    >>> http://dwb.unl.edu/Teacher/NSF/C01/C01Links/www.ualberta.ca/~bderksen/florin.html

    >>
    >>
    >> Thanks, Oldus Fartus, glass is a liquid just as I thought.

    >
    > Well, no it isn't according to both those links (but you have to read them
    > in their entirety). The general consensus was
    > "Glasses are amorphous solids. There is a fundamental structural divide
    > between amorphous solids (including glasses) and crystalline solids.
    > Structurally, glasses are similar to liquids, but that doesn't mean they
    > are liquid. It is possible that the "glass is a liquid" urban legend
    > originated with a misreading of a German treatise on glass
    > thermodynamics."
    >


    watched a TV prog on Discovery, called "how it's made", on glass, and that
    finished by saying that after around 20-30 years, a pane of window glass
    ends up thicker at the bottom than the top, but ever so slightly. It was
    stated in that prog, that glass was a liquid.

    P.
     
    Flyer, Aug 11, 2006
    #7
  8. Ctrl¤/Alt¤/Del¤

    Whiskers Guest

    On 2006-08-11, Flyer <> wrote:

    snip

    > watched a TV prog on Discovery, called "how it's made", on glass, and that
    > finished by saying that after around 20-30 years, a pane of window glass
    > ends up thicker at the bottom than the top, but ever so slightly. It was
    > stated in that prog, that glass was a liquid.


    Whoever made that programme needs to go back to school.

    ..-<http://dwb.unl.edu/Teacher/NSF/C01/C01Links/www.ualberta.ca/~bderksen/florin.html>
    | [...]
    |
    | The Antique Windowpanes Story
    |
    | The question of antique windowpanes has been addressed by Plumb, 1989[2].
    | He noted the following:
    |
    | [...W]hy are the panes of antique window glass thicker on the bottom than
    | the top? There really are observable variations in thickness, although
    | there seem to have been no statistical studies that document the frequency
    | and magnitudes of such variations. This author believes that the correct
    | explanation lies in the process by which window panes were manufactured at
    | that time: the Crown glass process.
    |
    | In other words, while some antique windowpanes are thicker at the bottom,
    | there are no statistical studies to show that all or most antique
    | windowpanes are thicker at the bottom than at the top. The variations in
    | thickness of antique windowpanes has nothing to do with whether glass is a
    | solid or a liquid; its cause lies in the glass manufacturing process
    | employed at the time, which made the production of glass panes of constant
    | thickness quite difficult.
    |
    | [...]
    |
    | [2] <http://dwb.unl.edu/Teacher/NSF/C01/C01Links/www.ualberta.ca/~bderksen/florin.html#plu>
    '-----

    See also <http://math.ucr.edu/home/baez/physics/General/Glass/glass.html>

    --
    -- ^^^^^^^^^^
    -- Whiskers
    -- ~~~~~~~~~~
     
    Whiskers, Aug 11, 2006
    #8
  9. Ctrl¤/Alt¤/Del¤

    Ponder Guest

    Ponder, Aug 11, 2006
    #9
  10. On Fri, 11 Aug 2006 05:46:48 GMT, Ctrl¤/Alt¤/Del¤
    <Ctrl¤/Alt¤/Del¤@cad.com> wrote:

    >>>Is glass a solid or a liquid?

    >>
    >>Technically, glass is a liquid--the most viscous liquid on Earth.

    >
    >That is what I was thinking, Michael. I don't really believe that it
    >is just an urban legend that glass is a liquid. Oldus Fartus is being
    >very helpful, I just think he may be wrong. I mean, glass really has
    >no defined melting point. Everyone knows that a true solid has a well
    >defined melting point and glass doesn't possess this quality.


    I couldn't get as technical as a couple of other respondents, and I
    didn't do a net search. I did once see a program that addressed the
    issue, and gave as an example the wavy glass that is found in older
    houses. It was such an odd bit of information that I never forgot it.

    If one listens long enough, one can hear anything. I once heard that
    concrete never dries 100%. I don't even want to discuss that. LOL

    I was in elementary school in the fifties. At the time, ions were never
    mentioned by my classmates, but I knew the basic definition. By that
    definition, a neutral ion was impossible. If anyone had asked me if
    there could be a neutral ion, I'd have said, "Of course, not!" Years
    later, I came upon the word "Zwitterion." Sure enough, it is a neutral
    ion--by virtue of how rapidly it switches between anion and cation.

    It probably takes a sound mind to envision glass as a liquid.

    _______________________
    School - Four walls with tomorrow inside.
     
    Michael A. Ball, Aug 11, 2006
    #10
  11. Ctrl¤/Alt¤/Del¤

    Old Gringo Guest

    Old Gringo, Aug 11, 2006
    #11
  12. Ctrl¤/Alt¤/Del¤

    Whiskers Guest

    On 2006-08-11, Michael A Ball <> wrote:
    > On Fri, 11 Aug 2006 05:46:48 GMT, Ctrl¤/Alt¤/Del¤
    > <Ctrl¤/Alt¤/Del¤@cad.com> wrote:
    >
    >>>>Is glass a solid or a liquid?
    >>>
    >>>Technically, glass is a liquid--the most viscous liquid on Earth.

    >>
    >>That is what I was thinking, Michael. I don't really believe that it
    >>is just an urban legend that glass is a liquid. Oldus Fartus is being
    >>very helpful, I just think he may be wrong. I mean, glass really has
    >>no defined melting point. Everyone knows that a true solid has a well
    >>defined melting point and glass doesn't possess this quality.


    What is the melting point of wood? Of course glass melts, so there has to
    be a temperature at which it changes from solid to liquid. It doesn't
    /crystalise/. Glass is not a liquid, nor is it a crystaline solid such as
    metal or ice; it's an amorphous solid.

    > I couldn't get as technical as a couple of other respondents, and I
    > didn't do a net search. I did once see a program that addressed the
    > issue, and gave as an example the wavy glass that is found in older
    > houses. It was such an odd bit of information that I never forgot it.


    The wavy glass in old houses was brand new wavy glass in brand new houses,
    originally. You can still get brand new wavy glass, eg to replace broken
    panes in an old building without spoiling the appearance. Flat sheets of
    glass used to be horribly expensive, as thick wavy glass had to be ground
    and polished to make "plate glass".

    We now have "float glass" where large flat sheets of glass are cheap and
    quick to produce by floating molten glass on the surface of molten tin,
    invented by Pilkingtons in the 1950s; this is actually cheaper than the old
    methods:-

    Blowing a cylinder of glass then cutting it lengthwise as it cools and
    letting it settle flat (hence a certain waviness and irregular
    thickness) - you can get sheets of more than a couple of feet across
    by this method. 19th century.

    Or taking a blob of molten glass and trying to flatten it before it
    solidifies - "crown glass", which has to be cut into small bits and
    sorted into grades of different size and thickness; each small piece
    will be thinner at one edge than at the other, and probably very wavy -
    the thickest part of the sheet is the 'bullseye' at the centre, which
    would normally be re-cycled unless pretty enough for ornamental use.
    These small panes were what made it necessary to have 'leaded lights'
    to glaze a usefully-sized window. Medieval.

    > If one listens long enough, one can hear anything. I once heard that
    > concrete never dries 100%. I don't even want to discuss that. LOL


    Ah, well, it can happen ...

    > I was in elementary school in the fifties. At the time, ions were never
    > mentioned by my classmates, but I knew the basic definition. By that
    > definition, a neutral ion was impossible. If anyone had asked me if
    > there could be a neutral ion, I'd have said, "Of course, not!" Years
    > later, I came upon the word "Zwitterion." Sure enough, it is a neutral
    > ion--by virtue of how rapidly it switches between anion and cation.
    >
    > It probably takes a sound mind to envision glass as a liquid.


    Especially when it breaks ... <G>

    > _______________________
    > School - Four walls with tomorrow inside.


    .... and reality outside?

    --
    -- ^^^^^^^^^^
    -- Whiskers
    -- ~~~~~~~~~~
     
    Whiskers, Aug 11, 2006
    #12
  13. Ctrl¤/Alt¤/Del¤

    joevan Guest

    On Fri, 11 Aug 2006 16:08:27 +0100, Whiskers
    <> wrote:

    >On 2006-08-11, Michael A Ball <> wrote:
    >> On Fri, 11 Aug 2006 05:46:48 GMT, Ctrl¤/Alt¤/Del¤
    >> <Ctrl¤/Alt¤/Del¤@cad.com> wrote:
    >>
    >>>>>Is glass a solid or a liquid?
    >>>>
    >>>>Technically, glass is a liquid--the most viscous liquid on Earth.
    >>>
    >>>That is what I was thinking, Michael. I don't really believe that it
    >>>is just an urban legend that glass is a liquid. Oldus Fartus is being
    >>>very helpful, I just think he may be wrong. I mean, glass really has
    >>>no defined melting point. Everyone knows that a true solid has a well
    >>>defined melting point and glass doesn't possess this quality.

    >
    >What is the melting point of wood? Of course glass melts, so there has to
    >be a temperature at which it changes from solid to liquid. It doesn't
    >/crystalise/. Glass is not a liquid, nor is it a crystaline solid such as
    >metal or ice; it's an amorphous solid.
    >
    >> I couldn't get as technical as a couple of other respondents, and I
    >> didn't do a net search. I did once see a program that addressed the
    >> issue, and gave as an example the wavy glass that is found in older
    >> houses. It was such an odd bit of information that I never forgot it.

    >
    >The wavy glass in old houses was brand new wavy glass in brand new houses,
    >originally. You can still get brand new wavy glass, eg to replace broken
    >panes in an old building without spoiling the appearance. Flat sheets of
    >glass used to be horribly expensive, as thick wavy glass had to be ground
    >and polished to make "plate glass".
    >
    >We now have "float glass" where large flat sheets of glass are cheap and
    >quick to produce by floating molten glass on the surface of molten tin,
    >invented by Pilkingtons in the 1950s; this is actually cheaper than the old
    >methods:-
    >
    > Blowing a cylinder of glass then cutting it lengthwise as it cools and
    > letting it settle flat (hence a certain waviness and irregular
    > thickness) - you can get sheets of more than a couple of feet across
    > by this method. 19th century.
    >
    > Or taking a blob of molten glass and trying to flatten it before it
    > solidifies - "crown glass", which has to be cut into small bits and
    > sorted into grades of different size and thickness; each small piece
    > will be thinner at one edge than at the other, and probably very wavy -
    > the thickest part of the sheet is the 'bullseye' at the centre, which
    > would normally be re-cycled unless pretty enough for ornamental use.
    > These small panes were what made it necessary to have 'leaded lights'
    > to glaze a usefully-sized window. Medieval.
    >
    >> If one listens long enough, one can hear anything. I once heard that
    >> concrete never dries 100%. I don't even want to discuss that. LOL

    >
    >Ah, well, it can happen ...
    >
    >> I was in elementary school in the fifties. At the time, ions were never
    >> mentioned by my classmates, but I knew the basic definition. By that
    >> definition, a neutral ion was impossible. If anyone had asked me if
    >> there could be a neutral ion, I'd have said, "Of course, not!" Years
    >> later, I came upon the word "Zwitterion." Sure enough, it is a neutral
    >> ion--by virtue of how rapidly it switches between anion and cation.
    >>
    >> It probably takes a sound mind to envision glass as a liquid.

    Water, as ice breaks too.
    >Especially when it breaks ... <G>
    >
    >> _______________________
    >> School - Four walls with tomorrow inside.

    >
    >... and reality outside?

    Maybe a different topic but you reminded me that oil paint does not
    dry, it cross links. As concrete does not dry it sets.
    Looking at a chart ie. oil paint in a hundred years goes down very
    quickly and then is practically flat for many year after the first
    year or so.
    I didn't read all the thread so maybe this is unneeded. Mea culpa if
    so.
    --
    "Politicians are like diapers. They should both be changed frequently
    and for the same reason."
     
    joevan, Aug 11, 2006
    #13
  14. Ctrl¤/Alt¤/Del¤

    sam Guest

    Ctrl¤/Alt¤/Del¤ wrote:
    > Is glass a solid or a liquid?
    >
    > Thanks,
    >
    > Alt


    It is a supercooled liquid.
     
    sam, Aug 11, 2006
    #14
  15. Ctrl¤/Alt¤/Del¤

    fkasner Guest

    Flyer wrote:
    > "Oldus Fartus" <> wrote in message
    > news:44dc0f6e$0$15974$...
    >> Ctrl¤/Alt¤/Del¤ wrote:
    >>> On Fri, 11 Aug 2006 12:21:16 +0800, Oldus Fartus
    >>> <> wrote:
    >>>
    >>>> Ctrl¤/Alt¤/Del¤ wrote:
    >>>>> Is glass a solid or a liquid?
    >>>> Good question!
    >>>>
    >>>> A couple of good essays are at
    >>>> http://math.ucr.edu/home/baez/physics/General/Glass/glass.html and
    >>>> http://dwb.unl.edu/Teacher/NSF/C01/C01Links/www.ualberta.ca/~bderksen/florin.html
    >>>
    >>> Thanks, Oldus Fartus, glass is a liquid just as I thought.

    >> Well, no it isn't according to both those links (but you have to read them
    >> in their entirety). The general consensus was
    >> "Glasses are amorphous solids. There is a fundamental structural divide
    >> between amorphous solids (including glasses) and crystalline solids.
    >> Structurally, glasses are similar to liquids, but that doesn't mean they
    >> are liquid. It is possible that the "glass is a liquid" urban legend
    >> originated with a misreading of a German treatise on glass
    >> thermodynamics."
    >>

    >
    > watched a TV prog on Discovery, called "how it's made", on glass, and that
    > finished by saying that after around 20-30 years, a pane of window glass
    > ends up thicker at the bottom than the top, but ever so slightly. It was
    > stated in that prog, that glass was a liquid.
    >
    > P.
    >
    >


    That was a common misconception based on historically old glass where
    the material was though to flow over long time. However it appears that
    by convention glazers would put the thicker end of glass at the bottom
    in an installation.

    However, glass is a liquid. It is a supercooled liquid. Supercooled
    liquids are liquids that have either a difficult crystal structure to
    spontaneously form as the liquid is cooled to a temperature where it
    should become a solid. There are other good common examples of
    supercooled liquids. Gycerol (commonly called glycerine) is at room
    temperature a supercooled liquid. It can with little difficulty be
    cooled to well below its freezing point without any apparent freezing.
    However if a crystal of solid glycerol or some other solid which is
    isomorphous with glycerol (a very similar crystal structure) is dropped
    into the cooled glycerol it will crystallize.

    So in finality, glass is a super cooled liquid. Any supercooled liquid
    if very viscous can frequently be supercooled to the point where it
    becomes a pseudosolid because it can no longer readily form a real solid
    with a well defined crystal structure.

    FK
     
    fkasner, Aug 11, 2006
    #15
  16. Ctrl¤/Alt¤/Del¤

    fkasner Guest

    Michael A. Ball wrote:
    > On Fri, 11 Aug 2006 05:46:48 GMT, Ctrl¤/Alt¤/Del¤
    > <Ctrl¤/Alt¤/Del¤@cad.com> wrote:
    >
    >>>> Is glass a solid or a liquid?
    >>> Technically, glass is a liquid--the most viscous liquid on Earth.

    >> That is what I was thinking, Michael. I don't really believe that it
    >> is just an urban legend that glass is a liquid. Oldus Fartus is being
    >> very helpful, I just think he may be wrong. I mean, glass really has
    >> no defined melting point. Everyone knows that a true solid has a well
    >> defined melting point and glass doesn't possess this quality.

    >
    > I couldn't get as technical as a couple of other respondents, and I
    > didn't do a net search. I did once see a program that addressed the
    > issue, and gave as an example the wavy glass that is found in older
    > houses. It was such an odd bit of information that I never forgot it.
    >
    > If one listens long enough, one can hear anything. I once heard that
    > concrete never dries 100%. I don't even want to discuss that. LOL
    >
    > I was in elementary school in the fifties. At the time, ions were never
    > mentioned by my classmates, but I knew the basic definition. By that
    > definition, a neutral ion was impossible. If anyone had asked me if
    > there could be a neutral ion, I'd have said, "Of course, not!" Years
    > later, I came upon the word "Zwitterion." Sure enough, it is a neutral
    > ion--by virtue of how rapidly it switches between anion and cation.
    >
    > It probably takes a sound mind to envision glass as a liquid.
    >
    > _______________________
    > School - Four walls with tomorrow inside.


    Stuff that forms solids do NOT have to have a well defined freezing
    point. A mixture will form a variety of mixtures (as the composition
    changes while cooling) that will form in some cases precise freezing
    points and in other cases a range of temperatures over which the solid
    forms. It is difficult to get precise melting points for a mixture as
    the mp (or fp) changes with composition. A common experiment in first
    year college chemistry is to determine melting point of a solution of a
    solid dissolved in a liquid and to compare it to the mp of the pure
    solvent. (Common combination would be naphthalene dissolved in benzene
    or in paradichlorobenzene.) This is used to determine the molecular mass
    of the solute molecule. The fp of the mixture changes with composition
    as the solid freezes out of the mixture. You have to know how to
    extrapolate the fp for the first appearance of the solid crystals in the
    mixture.

    Because liquid glass (whether "lime - soda" glass or borosiicate (Pyrex)
    glass) is so viscous near the fp of the mixture that it is almost
    impossible to get it to crystallize as you cool it.

    FK
     
    fkasner, Aug 11, 2006
    #16
  17. Ctrl¤/Alt¤/Del¤

    Avenger© Guest

    On Fri, 11 Aug 2006 04:04:12 GMT, Ctrl¤/Alt¤/Del¤
    <Ctrl¤/Alt¤/Del¤@cad.com> wrote:

    >Is glass a solid or a liquid?
    >
    >Thanks,
    >
    >Alt


    Actually I like to think of glass as a solid, which holds the liquid
    (amber liquid that is).
    --
    Avenger©
    I *HATE* Spam
    A Spam Hater Since 1951
     
    Avenger©, Aug 11, 2006
    #17
  18. Ctrl¤/Alt¤/Del¤

    clot Guest

    Avenger© wrote:
    > On Fri, 11 Aug 2006 04:04:12 GMT, Ctrl¤/Alt¤/Del¤
    > <Ctrl¤/Alt¤/Del¤@cad.com> wrote:
    >
    >> Is glass a solid or a liquid?
    >>
    >> Thanks,
    >>
    >> Alt

    >
    > Actually I like to think of glass as a solid, which holds the liquid
    > (amber liquid that is).


    After having imbibed far too much of the contents of a glass bottle from
    the northern fringe of Britain, I have found in the past that the bottle
    takes on some amorphous and liquid-like shapes.
     
    clot, Aug 12, 2006
    #18
  19. Ctrl¤/Alt¤/Del¤

    Guest

    Whiskers <> wrote:

    >On 2006-08-11, Flyer <> wrote:
    >
    >snip
    >
    >> watched a TV prog on Discovery, called "how it's made", on glass, and that
    >> finished by saying that after around 20-30 years, a pane of window glass
    >> ends up thicker at the bottom than the top, but ever so slightly. It was
    >> stated in that prog, that glass was a liquid.


    >Whoever made that programme needs to go back to school.


    I got the same info on Mechanical Universe by PBS. Replied as much on
    alt.folklore.urban (many years ago) and found my first flame war -
    it's troll material :)

    >See also <http://math.ucr.edu/home/baez/physics/General/Glass/glass.html>


    "Conclusion

    There is no clear answer to the question "Is glass solid or liquid?".
    "

    Same link in response to other replies

    "The use of the term "supercooled liquid" to describe glass still
    persists, but is considered by many to be an unfortunate misnomer that
    should be avoided. "

    Just depends upon which website you link to, to support either claim
    :)


    --
    All things Hubble
    http://www.spacetelescope.org/videos/archive/topic/dvd//
     
    , Aug 12, 2006
    #19
  20. Ctrl¤/Alt¤/Del¤

    Jimchip Guest

    On 2006-08-11, Michael A Ball <> wrote:
    [snip]
    > I couldn't get as technical as a couple of other respondents, and I
    > didn't do a net search. I did once see a program that addressed the
    > issue, and gave as an example the wavy glass that is found in older
    > houses. It was such an odd bit of information that I never forgot it.


    You have what I call "good, practical knowledge". You know what
    something is and your "odd bit of information" sticks as unusual. The
    eye for the anomaly is a good thing to have. Here are some basic
    definitions that I think you'll agree with:

    Solid: maintains its shape and volume
    Liquid: maintains its volume but adopts the shape of it's container
    Gas: Adopts the shape and volume of its container.

    All of the above are empirical definitions assuming constant temperature
    and pressure. A lot of other stuff in this thread is sorta half-baked
    theoretical concoction. It's good not to be too technical about states
    of matter unless one wants to get *really* technical, so that's why I
    think you had the right approach. FYI, there are two other states of
    matter, the BEC (Bose-Einstein Condensate) and Plasma.

    > If one listens long enough, one can hear anything. I once heard that
    > concrete never dries 100%. I don't even want to discuss that. LOL


    Define "wet" and "dry". I don't want to discuss that either :)

    > I was in elementary school in the fifties. At the time, ions were never
    > mentioned by my classmates, but I knew the basic definition. By that
    > definition, a neutral ion was impossible. If anyone had asked me if
    > there could be a neutral ion, I'd have said, "Of course, not!" Years
    > later, I came upon the word "Zwitterion." Sure enough, it is a neutral
    > ion--by virtue of how rapidly it switches between anion and cation.


    Just to clear up the above a bit, the most common zwitterions ("double"
    or "twinned" ions) are the amino acids at their, so called, isoelectric
    point. They are not "switching between" but relatively permanent cation
    *and* anion. Amino acids have an amino group capable of achieving a +
    (cationic) charge and a carboxylic acid group capable of of achieving a
    - (anionic) charge. The isoelectric point is the pH at which the amino
    acid is overall neutral in spite of the fact it has net + and - charges.

    > It probably takes a sound mind to envision glass as a liquid.


    Envisioning can be dangerous for any mind. The questions for any
    substance might be: "What properties does one observe?" and "What
    empirical definitions are most useful in describing the observations?"

    I'll put my money on glass *acting* like a solid before I would try to
    use it as if it were a liquid.

    --
    Variables don't; constants aren't.
     
    Jimchip, Aug 12, 2006
    #20
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    bigal, Feb 5, 2006, in forum: Case Modding
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  5. DarkMan

    printed pictures stick to frame glass.

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    Views:
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