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Science

How Ice Melts 276

Posted by Zonk from the i-can-sleep-tonight dept.
Killer Instinct writes "Ever wonder how ice melts? Until now, scientists could not explain why ice cubes in your drink melt. They've known the basics, but the details remained elusive. A breakthrough new study, announced yesterday, supports a leading theory that melting starts when the fundamental structure of matter begins to crack. Melting is considered a basic phenomenon in physics. An understanding of how it works is crucial to gaining a firm grasp on the physical world."
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How Ice Melts More

How Ice Melts

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  • Hmmmmm... (Score:4, Funny)

    by chriswaclawik ( 859112 ) on Saturday July 02, 2005 @12:51AM (#12967291)
    Ever wonder how ice melts?

    No.

    • Re:Hmmmmm... (Score:5, Funny)

      by turtled ( 845180 ) on Saturday July 02, 2005 @01:04AM (#12967354)
      I didn't read the full article earlier, was this one of the top 125 Big Science questions?

    • Re:Hmmmmm... (Score:5, Informative)

      by poopdeville ( 841677 ) on Saturday July 02, 2005 @01:07AM (#12967371)
      That's a shame. This is a very interesting topic. We've known for centuries that melting is related to heat, and there are molecular models of freezing. Namely, water molecules tend to align themselves in a crystalline structure unless they're stirred up. A region freezes when the average kinetic energy is low enough for the molecules to align themselves. Consider a fairly large volume of water -- in macroscopic scales. Heat conduction through liquid water is faster than through ice, because of convection. So the macroscopic freezing process isn't reversible. (There are other reasons why the process isn't reversible, but one suffices)

      This means that a different process is responsible for macroscopic melting. Since macroscopic chunks of ice tend to be imperfect crystals, it stands to reason that the weak unions between crystalline structures facillitate melting.

      • Nope, freezing and melting are both entirely reversible processes, in the thermodynamic sense. For them to not be reversible, there would have to be an increase in entropy somewhere.

        And it's the same "process" involved. The biggest difference between melting and freezing is that freezing requires the nucleation of a crystal, which is a time-dependent process. Melting can generally occur without it.

    • How grass grows, the scientific miracle!

    • Re:Hmmmmm... (Score:5, Funny)

      by mizhi ( 186984 ) on Saturday July 02, 2005 @03:10AM (#12967725)
      An understanding of how it works is crucial to gaining a firm grasp on the physical world.
      Really? I don't really understand it and I seem to be able to grasp objects just fine.

  • Anti-Cold (Score:5, Funny)

    by TimeTraveler1884 ( 832874 ) on Saturday July 02, 2005 @12:53AM (#12967299)
    Ever wonder how ice melts?
    Not really. But I have a hypothesis that it has something to do with heat or as I call it, "anti-cold." There seems to be a relationship between 0 degrees Celsius and ice melting. Likewise a relationship with 100 degrees Celsius and water boiling (when under one atmosphere of pressure). There must be some underlying mathematical connection; for these events and their temperatures surely can not be coincidence. Some day I will solve this mystery, but only when I am properly funded by government grants.

    • Re:Anti-Cold (Score:5, Insightful)

      by NanoGator ( 522640 ) on Saturday July 02, 2005 @12:58AM (#12967324) Homepage Journal
      "Not really. But I have a hypothesis that it has something to do with heat or as I call it, "anti-cold."

      I like how people bitch about the lack of 'news for nerds' on this site lately. Then, when something comes along that's truely nerd worthy, everybody becomes a smart ass.
      • It's just our way of expressing our joy in the nerd-worthiness.
      • Blockquoth the poster:

        Then, when something comes along that's truely nerd worthy, everybody becomes a smart ass.

        Oh, I'm pretty sure they're already smartasses; they just get the opportunity to show it off... :)
    • Stop modding me Insightful. I was fucking joking!

      But if people really didn't know that the Celsius scale was defined with 0 as the freezing point of water and 100 as the boiling point; well glad I could be useful. There is no mysterious alien mathematical connection, us humans defined the "connection".

      • But if people really didn't know that the Celsius scale was defined with 0 as the freezing point of water and 100 as the boiling point; well glad I could be useful.

        Actually, the original value for freezing in the Centigrade scale was 100 and boiling was zero. It wasn't changed until the mid 1700's.

        • Re:Not Insightful or Interesting (Score:4, Informative)

          by Kidbro ( 80868 ) on Saturday July 02, 2005 @09:17AM (#12968463)
          Actually, the original value for freezing in the Centigrade scale was 100 and boiling was zero. It wasn't changed until the mid 1700's.

          While what you're saying is true, I think that the way you put it may give people reason to exaggerate the life span of the original scale. The original system was proposed in 1742, and modified to its current version in 1747. Both are years I'd say qualify for the being part of "the mid 1700's".

          Reference [wikipedia.org].

    • Re:Anti-Cold (Score:5, Funny)

      by learn fast ( 824724 ) on Saturday July 02, 2005 @01:17AM (#12967402)
      The real reason of course, which you wouldn't know from reading the pseudo-scientific raving of the parent poster, is that melting is an adaptive response to a changing environment.

      You see, most water was burned at an earlier time. So, when it encounters heat it melts out of fear! It melts to more effectively evade what it expects might be a dangerous encounter. This also explains why water melts faster when it is shaken upside-down and verbally threatened.

      Some people think that this proves that water is less-than-rational, however it's clear to me that it is an adaptive response. The kind of therapy that would get it out of that kind of feedback loop is much to expensive for most water to afford, anyway. Most people don't realize that there are whole water galaxies, where water can more easily acheive economic unanimity.

      This simple theory explains so much evidence. Why do we see so little water inside of volcanoes? Inside of airplane engines? Or inside of stoves? It's because water fears heat! Based on an earlier, traumatic reaction that must have occurred sometime in its past.

      I'll be here waiting for my Nobel Prize. Is the king of Sweden's daughter hot? Prolly.
    • but only when I am properly funded by government grants.

      Man, we have things wrong. Screw the grants.

      1. Create a company. Call it hulliburton.
      2. Hire one of the bush twins and label her as CEO.
      3. Get LOTS of government money for nothing.
      4. PROFIT!!!!!
  • I guess I thought we woulda had this one nailed down by now! What will scence reveal that we don't know next?
    • Hey, thats a serious point - the world is not flat, the earth is not the center of the solar system, objects in motion do not naturally tend to stop without outside influence, the world was not made in 7 days, time is not independant of your frame of reference, at a microscopic level the world is not deterministic, etc... Often the most fundamental discoveries in science show that we don't know what we thought we knew.

  • It's about time... (Score:4, Funny)

    by SpartanVII ( 838669 ) on Saturday July 02, 2005 @12:53AM (#12967304)
    I can finally sleep at night!
  • Ever wonder why Earths orbit is fairly round.. while most other planets are elliptical?

    I think matter is ON crack...\

  • Not suprising (Score:4, Interesting)

    by cyberfunk2 ( 656339 ) on Saturday July 02, 2005 @12:55AM (#12967311)
    This is somewhat akin to boiling really, at least from my perspective.. small nucleation points, that spread throughout the liquid or crystal, effecting an overall phase change when the energy distribution reaches a point such that the majority of atoms prefer the gaseous or liquid state (depending on the phase change).

  • Wait... (Score:5, Funny)

    by Anonymous Coward on Saturday July 02, 2005 @12:55AM (#12967314)
    Wait wait wait, let me get this straight. We put a man on the moon, developed flying machines composed of several hundred tons of steel, and we just now BARELY explain why Ice Cubes melt in our drink? You know, sometimes humanity really is....scary. What'll be truly frightning is if scientists come out with an explanation as to why Ice Cube still gets movie roles.
    • What people fail to understand is how strangely complicated the world is. Putting a man on the moon is a matter of figuring out the proper nonlinear dynamic control equations which is pretty much classical physics and (really hard) math. Something like the thermodynamic properties of matter at a molecular level requires a lot more research due to how freaky the universe gets at that small of a scale. Similarly, figuring out how the human body works (modern medical science is akin to fixing a car with a sled

      • Re:Wait... (Score:4, Insightful)

        by jpostel ( 114922 ) on Saturday July 02, 2005 @07:52AM (#12968269) Homepage Journal
        One of my college professors in materials science, that retired from Bell Labs to teach, used to say, "I'm pretty sure this is how it works, but I'm not positive. If anyone tells you he is positive, he's either lying, or not smart enough to check that the underlying facts are actually suppositions."

        He once told us that he didn't really know how resistors worked, but he did know that if he manufactured them using certain materials in a certain process, he could get resistors that were a certain number of ohms. Today resistors are manfactured all over the world pretty much the same way, but the methods were derived from trial and error, and not some deeper understanding and equations for making the best resistor.

  • Ever wonder why ice melts? (Score:4, Interesting)

    by Omkar ( 618823 ) on Saturday July 02, 2005 @12:57AM (#12967316) Homepage Journal
    a. Summary is plagiarized from the article, unless I've missed some nested quotes.
    b. These guys took this problem because "the earliest phase of melting has never been seen" but they didn't do that either! All they did was make "see-through crystals that are like small beads and are visible in an optical microscope." Doesn't sound like a hell of a lot of progress to me; anyone care to elaborate?
    c. Their main result seems to be that the melting process starts at crystal defects and spreads to create liquidy regions within the crystal. Again, can anyone explain why the melting might not start at defects - the weak points?
    I'm sure there's something neater here than I'm seeing; it would be nice if the article had more info.
    • Yes, I was wondering what this discovery will actually pave the way for. I am sure somebody will figure something out. Personally, I am still waiting for the solution for Superstring theory.

  • The awesome power of Pykrete! (Score:3, Interesting)

    by Grendel Drago ( 41496 ) on Saturday July 02, 2005 @12:58AM (#12967325) Homepage
    Speaking of ice, have folks here ever heard of Pykrete [wikipedia.org]? And would this explain why Pykrete melts so slowly?

    Supposedly tissue paper works as well as sawdust. So you can tell all your friends you know how to beat someone to death with a wet paper towel.

    --grendel drago

  • Great... (Score:3, Funny)

    by Anonymous Coward on Saturday July 02, 2005 @01:02AM (#12967341)
    Now how long till they can whip-up a batch of Ice-Nine and freeze the whole planet?

  • Killer Instinct is Robert Roy Britt? (Score:5, Insightful)

    by Osty ( 16825 ) on Saturday July 02, 2005 @01:03AM (#12967347)

    From the article submission:

    Until now, scientists could not explain why ice cubes in your drink melt. They've known the basics, but the details remained elusive. A breakthrough new study, announced yesterday, supports a leading theory that melting starts when the fundamental structure of matter begins to crack. Melting is considered a basic phenomenon in physics. An understanding of how it works is crucial to gaining a firm grasp on the physical world.
    And from the actual article itself:

    Until now, scientists could not explain why ice cubes in your drink melt. They've known the basics, but the details remained elusive.

    A breakthrough new study, announced today, supports a leading theory that melting starts when the fundamental structure of matter begins to crack.

    Melting is considered a basic phenomenon in physics. An understanding of how it works is crucial to gaining a firm grasp on the physical world.

    Those look pretty similar to me! Given that the article submission is word-for-word exactly from the article itself, it's fair to assume that the submitter, Killer Instinct, is the same person as the author of the article, Robert Roy Britt. How else could the same text be attributed to two supposedly different people?

    If you're going to submit an article, summarize it in your own words. If you're just going to paste in the first few sentences of the article, attribute them to the proper author by using a phrase such as, "Quoted from the article: 'insert quote here'." Removing line breaks is not enough to satisfy the "summarize in your own words" criteria.

    Here's an example of what the submission should've looked like if Slashdot cared at all about given proper attribution for written text:

    Killer Instinct writes "Ever wonder how ice melts? From the article: 'Until now, scientists could not explain why ice cubes in your drink melt. They've known the basics, but the details remained elusive. A breakthrough new study, announced yesterday, supports a leading theory that melting starts when the fundamental structure of matter begins to crack. Melting is considered a basic phenomenon in physics. An understanding of how it works is crucial to gaining a firm grasp on the physical world.'"
  • She's melting! She's melting!

  • Ah, as usual.... (Score:3, Insightful)

    by jtbauki ( 838979 ) on Saturday July 02, 2005 @01:06AM (#12967365)

    ...smartass slashdotters crack jokes about a new discovery to hide their own insecurities. I, for one, freely admit I have no idea how ice melts.

    1+1=2 anyone?

  • Accuracy ? (Score:3, Interesting)

    by cyberfunk2 ( 656339 ) on Saturday July 02, 2005 @01:06AM (#12967366)
    At least the way the article describes the study.. it doesnt seem like it models the problem well.. but something tells me these arent the greatest writers here... For instance:

    "So Yodh's team made some big atoms. Specifically, they made see-through crystals that are like small beads and are visible in an optical microscope."

    By "see-through crystals" i'm assuming they mean optically transparent crystals constructed from small beads, not crystals that are like beads that then form a larger crystal structure, although from the wording, it's impossible to tell.

    "The spheres swell or collapse significantly with small changes in temperature, and they exhibit other useful properties that allow them to behave like enormous versions of atoms for the purpose of our experiment,"

    As far as I know.. atoms dont significantly change size when temperature changes.... they change how fast they move. I dont really see how size-changing beads model water molecules here, unless it's on a macroscale where a molecules are considered to expand as a group with increased temperature... but that sort of would defeat the pupose of the whole study...

    On the other hand.... I think that the research is probably solid, espcially if it's being published in Science, a extremely selective journal. I think the article just fails to explain it well, and takes quotes out of context. Sadly, this is all too common in scientific journalism.
  • I think the opposite problem is more interesting: Why does liquid take forever to get to the boiling point and then rapidly increase in temperature?

    I always burn the gravy sauce since I'm distracted when it finally reaches the boiling point. Cooking should be easier than this.
    • I think the opposite problem is more interesting: Why does liquid take forever to get to the boiling point and then rapidly increase in temperature?

      Problem solved: Liquids don't increase in temperature once they've reached their boiling point. Not as long as its in an open container so the surrounding pressure is constant.

      Once you reach the boiling point, the heat you add doesn't go towards raising the temperature, but towards vaporising the liquid.
    • It doesn't...once a liquid gets to the boiling point, it becomes a gas.
    • This is actually easily explained (although I suspect you were joking). Any liquid, including gravy has 3 important heat related constants. The "specific heat", which is how much heat is required to raise 1 kilogram of a substance 1 degree kelvin. The "heat of fusion", which is how much heat must be removed per kilogram to freeze the substance, and the "Heat of vaporization" which is how much heat must be added to vaporize (aka boil) the substance. The Specific heat of water is (from memory so I may
      • Initially, I was joking. But when the solution on how avoid burning the gravy became apparent, I got excited. Cooking gravy has always been my weak point when I was working in the resturant business for a few years.
    • The key is that water has a high specific energy, so it can absorb a lot of energy without actually increasing in temperature. The other types of molecules in your gravy solution can happily be heated to over 212 degrees without boiling; only the water boils. As more and more water cooks out of the gravy, there becomes less water to absorb the energy through evaporation so the energy begins heating the remaining non-water liquid to a higher temperature than water's boiing point.

      This is the entire methodo

      • The key is that water has a high specific energy, so it can absorb a lot of energy without actually increasing in temperature. The other types of molecules in your gravy solution can happily be heated to over 212 degrees without boiling; only the water boils.

        You are right in the broad overview, but wrong on the details. The boiling temperature of a mixture is not necessarily due to the boiling temperatures of its two components. The boiling temperature of a solution is not a linear combination of t

    • I think the opposite problem is more interesting: Why does liquid take forever to get to the boiling point and then rapidly increase in temperature?

      That's easy. Everybody knows that water will come to a boil faster when you're not watching it.

      Schroedinger's cat meets the melting is an adaptive response to a changing environment theory.

  • Bad reporting? (Score:3, Insightful)

    by Nigel Stepp ( 446 ) on Saturday July 02, 2005 @01:11AM (#12967388) Homepage
    This article is too bad; there's probably an interesting result here, but it appears to be shrouded in vagueness and analogy.

    It's true that the *exact* mechanism for melting has not been "seen", but the concepts really are well known. Our models are good enough that computer simulations can be very accurate. I have seen several which show features such as surface melting, for instance.

    Also, it is absolutely expected that melting begin at defects, but this does not mean that "melting begins below the melting point" as the article suggests. These areas are locally amorphous and there is no reason that they should begin melting at the crystal's melting point. Really, it's all in the free energy equations.

    I'm guessing that the real result has been butchered by the article.
  • Wow... I just realized that I read a whole article about ice melting... And I was interested. I guess that's what you're reduced to when you have nothing to do but read Slashdot at midnight on a Friday...

  • I am sure that Frosty the Snowman... (Score:5, Funny)

    by Brad1138 ( 590148 ) <brad1138@yahoo.com> on Saturday July 02, 2005 @01:16AM (#12967401)
    Is thrilled to know exactly how he will die come spring.

  • Crazy! (Score:2, Insightful)

    by Jah-Wren Ryel ( 80510 )
    An understanding of how it works is crucial to gaining a firm grasp on the physical world.

    I did not RTFA, and now I feel like I am tripping on acid - swallowing colors of the sound I hear, I am just a crazy guy.

    Slashdot, it's better than drugs!
    It will make you innn-sane!!

  • So How Does Water Freeze? (Score:3, Informative)

    by guygee ( 453727 ) on Saturday July 02, 2005 @01:21AM (#12967419)
    It turns out that, at the molecular level, nodody knows the answer to this question, either, especially in the presence of impurities. In fact, in general, the subject of "Phase Change" is something of a black art, full of "empirical models", a great dissapointment for a mind that lusts for explanations in terms of hard mathematics. Unfortunately, as a graduate EE taking this course in Chemical Engineering, my grade reflected my disappointment. (Aside: my grad work was done in connection with the Army Corp of Engineers Cold Regions Research and Engineering Lab, thus my unnatural interest in the topic. As the cold war with the USSR gave way to the hot wars in the Mideast, funding for research in the associated topics has dropped off).

  • Finally... (Score:2, Funny)

    by Treskin ( 555947 )
    the aliens will make contact. It would have been emberassing to make contact with planet that couldn't quite pin down the subtleties of how ice melts.
  • Would be if this will lead to learning about how to "melt" other solids. IANAS, so I am just guessing this is the tip of the iceberg [chuckle].

    Does carbon ever exist in a liquid state? Liquid diamonds?

  • If only they knew a way to melt Ice-9...

  • How, not why (Score:5, Insightful)

    by thomasdn ( 800430 ) on Saturday July 02, 2005 @01:43AM (#12967489) Homepage Journal

    Until now, scientists could not explain why ice cubes in your drink melt.

    Scientists does not explain why things happen. Only how.

  • Abstract (Score:3, Informative)

    by cyberfunk2 ( 656339 ) on Saturday July 02, 2005 @01:59AM (#12967529)
    Abstract from the actual Science article:: Much more informative than this silly article. Premelting is the localized loss of crystalline order at surfaces and defects for temperatures below the bulk melting transition. It can be thought of as the nucleation of the melting process. Premelting has been observed at the surfaces of crystals, but not within. We report observations of premelting at grain boundaries and dislocations within bulk colloidal crystals using real time video microscopy. The crystals are equilibrium close-packed three-dimensional colloidal structures made from thermally responsive microgel spheres. Particle tracking reveals increased disorder in crystalline regions bordering defects, the amount of which depends on the type of defect, distance from the defect, and particle volume fraction. Our observations suggest interfacial free energy is the crucial parameter for premelting, in colloidal and atomic scale crystals.
  • Global Warming causes ice to melt. Duh! Who posts this crap? Next they'll post a story about why a watched pot never boils.

    You heard the one about the Southern gentleman in a northern bar. He says to the Yankee waitress: "Excuse me Maam, I'd like a piece of ice."

    A short while later.

    "Well thank you, maam, but my drink's still warm."

    And if you don't get it, you have never heard a southerner say the word 'ice'. It rhymes with bass. Oh and people in Biloxi, MS think anyone who lives north of I-10 is a

  • Corollary (Score:4, Interesting)

    by EvilMidnightBomber ( 778018 ) on Saturday July 02, 2005 @02:28AM (#12967602) Homepage
    If "pre-melting" truly begins at the defect sites, it would be interesting to see whether ultra-low defect containing crystals melt at a higher temperature. Say, purify and grow a chunk of ice through the same procedure used to fabricate semiconductor grade silicon (Czochalski style or epitaxially), and then see if it holds together through warmer temps.
  • OK, how does "ice wouldn't melt in your mouth" work? Give it to me smoove, now.
  • "Ever wonder how ice melts? ... An understanding of how it works is crucial to gaining a _firm_ _grasp_ on the physical world."

    "Grab ahold of that ice!"
    "I can't! It's slippery!"
    "QUICK! Somebody do some SCIENCE!"

  • This just in.... (Score:2, Insightful)

    by Hydraulix ( 893404 )
    News flash!! Still no cure for cancer, but scientists are hard at work discovering how ice melts. Quick somebody start polishing that noble prize!
  • ...that's generally how I get the ice to melt.
  • patent it and make it GPL so we can all still have metling ice to cool our drinks.
  • This isn't exactly a simulation of melting, but it does involve simulation at a similar molecular level. The work that Fred Streitz and co. [llnl.gov] at Lawrence Livermore National Laboratory are doing explores the processes involved in the rapid resolidification of tantalum. They're reproducing, from first principles, some basic materials results like grain boundaries and such. It's one of the largest (if not the largest) simulation running the the world's largest supercomputer [llnl.gov]. One of my team members is doing t
  • "...fundamental structure of matter begins to crack..."
    The fundamental structure of matter? That would be subatomic physics. Ed.s: please get someone with a science background on board!

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