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A Liquid That Turns Solid When Heated

Roland Piquepaille writes "There are some sure things in life, such as death and taxes. When you are heating a solid, you expect it will melt and when you're boiling water, you're pretty certain that it will turn into vapor. But what about a liquid that becomes solid when it's heated? Of course, it has already been done, for example in the chemical process of polymerization. But now, PhysicsWeb writes that a team of French physicists has discovered a law-breaking liquid that defies the rules. When you heat it between 45 and 75C, it becomes solid. But the process is fully reversible, and this is a world's premiere. When you decrease the temperature, this solid melts and turns again into a liquid. I'm not sure of the implications of such a phenomenon, but it's fascinating. Read more for essential details."

62 of 450 comments (clear)

  1. Weird, but cool! by lesterchakyn · · Score: 5, Funny

    This is one of the things that makes you think if everything is as you know...

    The Matrix anyone?

    1. Re:Weird, but cool! by cynic10508 · · Score: 3, Insightful

      This is one of the things that makes you think if everything is as you know... The Matrix anyone?

      Ehhh. This is more what we know empirically. We're merely discovering a priori things that we weren't aware of previously. The Matrix was more about what we know epistemically.

    2. Re:Weird, but cool! by TykeClone · · Score: 4, Funny
      Can darwinism work on software bugs ?

      Yes - it's survival of the fittest. Those bugs that could hide the best (until they show up to bite you in the ass) will do so.

      --
      A fine is a tax you pay for doing wrong and a tax is a fine you pay for doing all right.
    3. Re:Weird, but cool! by boaworm · · Score: 3, Informative
      Eggs dont turn back to liquid when you cool them...

      Absolutely true. I was just trying to make fun of the very bad headline. The headline was "Science: A Liquid That Turns Solid When Heated", which is not at all interesting.


      Also eggs cooking is the water coming out.

      Now that is plain b-s. As I said, what happens is that when you add energy (heat) to the proteins, they re-fold and turns into a more stable substance, transforming from a liquid to a firm state.

      Just to clearify this so that people dont believe your disinformation. If you boil and egg, in water, with the eggshell intact, you still think you will boil the water away from the "egg", making it firm ? You are utterly wrong, and not informative at all. Even a simple google reveals this, look here or here.

      Go back to your cave, troll.

      --
      Probable impossibilities are to be preferred to improbable possibilities.
      Aristotele
    4. Re:Weird, but cool! by krunk7 · · Score: 3, Insightful

      Hehe, "discovering a priori things we weren't aware of" is somewhat of an oxymoron: Websters: a priori

    5. Re:Weird, but cool! by simcop2387 · · Score: 3, Funny

      2+2 isn't 4!! 4 doesn't exist, 2+2 = 11

  2. what it says by pbranes · · Score: 5, Insightful
    What it says:

    Plazanet and colleagues prepared a liquid solution containing a-cyclodextrine (alpha-CD), water and 4-methylpyridine (4MP). Cyclodextrines are cyclic structures containing hydroxyl end groups that can form hydrogen bonds with either the 4MP or water molecules.

    What I see:

    And if you expect me to tell you how this discovery will modify our lives, you're going to be disappointed. I've not a slightest idea about it, even if I find fascinating that scientists always find new ways to break rules and shake our certitudes.

    1. Re:what it says by Idarubicin · · Score: 4, Funny
      What I see:

      And if you expect me to tell you how this discovery will modify our lives, you're going to be disappointed. I've not a slightest idea about it, even if I find fascinating that scientists always find new ways to break rules and shake our certitudes.

      What I see:

      I am a chemist that has discovered a class of mixtures with a very interesting and heretofor unobserved property. I have published information on how to prepare these mixtures--in a way, it is a solution looking for a problem. I expect that given a small group of engineers, a dozen or so different applications could be hashed out over their morning coffee. I am disappointed--but not surprised--that a Slashdot reader couldn't be bothered to use his imagination to come up with an application, preferring to instead complain that no ideas were spoon-fed in the brief PhysicsWeb note.

      --
      ~Idarubicin
  3. speculation on applications? by Anonymous Coward · · Score: 3, Interesting

    so what could the application of such a material be? a new breed of thermometers are on their way, i guarantee it.

    thermometers for the 21st century and beyond.

    1. Re:speculation on applications? by theAedileDecimus · · Score: 5, Funny

      I can just imagine it now...

      You go to Target to buy a 12-pack of "One-Time Use Thermometers."
      Instructions: "When the temperature is between 45 and 75 degrees celcius, the liquid inside turns to a solid, shattering the glass! That's all there is to it!"

    2. Re:speculation on applications? by TWX · · Score: 5, Funny

      I think that my girlfriend is comprised of this stuff. She seems to suddenly turn frigid as soon as things heat up...

      --
      Do not look into laser with remaining eye.
  4. Cookie dough batter by Anonymous Coward · · Score: 3, Funny

    In other news:
    Cookie dough batter turns to solid in oven when heated. (Yeah, yeah, it's not reversible...)

    1. Re:Cookie dough batter by exick · · Score: 5, Funny

      On my planet, cookie dough batter is already a solid.

  5. What?! by Anita+Coney · · Score: 4, Funny

    No references to Ice nine?! I must be getting old.

    --
    If someone says he and his monkey have nothing to hide, they almost certainly do.
    1. Re:What?! by spellraiser · · Score: 3, Informative

      Good call. Here is a short explanation for those who are scratching their heads over what 'that program from The Recruit' might possibly have to do with solid liquids. Short answer: It doesn't; start reading more books!

      --
      I hear there's rumors on the Slashdots
  6. I read about this a while back.. by dat00ket · · Score: 4, Funny

    Fascinating stuff. This physics marvel of a liquid is a mixture of many separate elements... including milk, flour, eggs, sugar, and a pinch of salt.

  7. Now we can buy by Wizzy+Wig · · Score: 5, Funny

    a bag of "Hot Cubes" to keep the coffee warm.

    1. Re:Now we can buy by Colonel+Cholling · · Score: 4, Funny

      organic chemicals + you = death.

      So you live on a diet consisting exclusively of salt, sand, battery acid, and water? What, are you some kind of robot? If so, what are your powers? Do you use them for good, or for awesome?

      --

      I am Sartre of the Borg. Existence is futile.
    2. Re:Now we can buy by Anonymous Coward · · Score: 5, Funny
      organic chemicals + you = death
      Therefore,
      you = death - organic chemicals
      That doesn't seem right. Surely you meant
      you - organic chemicals = death
      Anyway,
      me - coffee = death
  8. Assassins take note! by Twisted+Grind · · Score: 4, Interesting
    The temperature at which it becomes a solid falls as the concentration of áCD increases.

    So...if you were to put this in someone's bloodstream with the right concentration, you could cause it to solidify once it reached standard body temperature...
    --
    You know you've lost it when you begin signing physical documents with =^_^=
    1. Re:Assassins take note! by EvilSporkMan · · Score: 3, Funny

      Putting it in someone's bloodstream would probably kill them ANYWAY - wouldn't cheaper poison be easier?

      --
      -insert a witty something-
  9. Gotta say it... by Anonymous Coward · · Score: 4, Funny

    Hell has officially frozen over now.

  10. Heat shield? by BigZaphod · · Score: 5, Insightful

    I don't know much about physics, but could something like this be used as a heat shield of some kind? Like, where the shield is basically considered turned off when it is in the liquid state. Then when it hits a certain overload temperature, it turns to a solid and thus blocks (some of) the heat exchange?

    1. Re:Heat shield? by novakyu · · Score: 5, Informative
      I don't know much about physics, but could something like this be used as a heat shield of some kind? Like, where the shield is basically considered turned off when it is in the liquid state. Then when it hits a certain overload temperature, it turns to a solid and thus blocks (some of) the heat exchange?

      That would probably depend on the property of the solid that forms when the solution is heated (is it a good insulator? what are its structural properties?), but I can think of one related application: temperature-controlled switch.

      The solution is transparent to visible light, whereas the solid that forms is not. Since this process depends on the temperature and is reversible, it's very simple to design a circuit (using a LED and phototransistor or some sort of photo-detector) that works as temperature-dependent switch. From what the article says,

      The temperature at which it becomes a solid falls as the concentration of CD increases.

      it should be possible to tweak the turn-on temperature to a degree.

      But then, this is not anything new--as far as dependence on temperature goes, there are many other materials that are probably more reliable (the only thing novel about this would be that its dependence is backward.)

      Back to the topic, yeah, it can probably be used as heat shield in a limited capacity: i.e. if it turns out that the liquid is transparent to infrared radiation while the solid isn't, this can be used as natural temperature-controlled infrared radiation shield (but of course, it will still be subject to heating due to other methods, like...conduction via the solid itself, unless the resulting solid turns out to be similar to styroform).

  11. Gets hard when you heat it? by garyisabusyguy · · Score: 5, Insightful

    Why do I see a new line of sex toys being based on this?

    Or at least a splint that packs down small but that remains rigid when in contact with a warm body.

    Um.. Maybe that would apply to a sex toy ;)

    --
    Wherever You Go, There You Are
    1. Re:Gets hard when you heat it? by srcosmo · · Score: 4, Funny
      I'm not sure, but one would probably have to be pretty damn horny to heat the thing up to 45C...
      :-/

      --
      free speach
      Did you mean: free speech
  12. actually . . . by ir0b0t · · Score: 4, Funny

    I think I've been drinking this stuff out of the coffee pot in my office for several years now.

    --
    I'm laughing at clouds.
  13. Missing some info here by Hockney+Twang · · Score: 5, Interesting

    It's a solid at those temperatures, what is it at higher temps? Liquid again? Does it have two melting points? At what temp does it vaporize? Does it freeze at some point below the normal low-end melting point? At 0 degrees Kelvin, it's definitely a solid, somewhere above that, a liquid, then a solid again, then a liquid again, then a vapor? Maybe.

    1. Re:Missing some info here by dat00ket · · Score: 4, Informative
      "At 0 degrees Kelvin, it's definitely a solid"

      I wouldn't be too sure about that.

      Bose-Einstein Condensate
      Superfluids

      First rule of physics: When you're dealing with extremes, things get funky.

    2. Re:Missing some info here by DavidTC · · Score: 5, Interesting
      At 0 degrees Kelvin, it's not anything. It's just, in theory, a bunch of suspended frozen stuff that's exactly where it was before you hit 0. It has no chemical properties, because there is no way to do any sort of chemical interaction with it.

      That's in theory, of couse, since you can't hit 0 degrees Kelvin.

      But assuming you mean 'near 0 Kelvin', like d00ket pointed out, things get really weird down there. Some substances don't appear to have freezing points, there is no state below 'liquid'...they just move slower and slower. And some freeze quite normally, then do another transition way down there where they move back to a liquid like substance.

      The substance in the article is interesting, but not completely amazing. Various 'states of matter' are just rules of thumb.

      --
      If corporations are people, aren't stockholders guilty of slavery?
    3. Re:Missing some info here by div_B · · Score: 3, Interesting

      But I thought it was simply a matter of temperature...it was just we don't have any way to get them down that low if they keep bouncing off each other.

      I could be wrong, but I think that many-body interactions can change the internal states of the atoms, which of course must be the same across the board for the condensate to form.

      In a nutshell, BECs are formed by applying a magnetic field, which is essentially a 3D SHO potential (mass on a spring). The atoms are cooled by lasers, craftily 'detuned' from the resonant frequency of the atoms, so that, due to the Doppler effect, atoms approaching the laser experience a retarding force, while atoms receding from the laser experience very little force. In this manner the gas sample can be cooled to ~1 microKelvin (?), which is still far too warm for condensation to occur.

      The magnetic field is then manipulated to form a 'cup' which holds the atoms. The walls of the 'cup' are gently rolled back, so that the most energetic of the atoms 'boil off' the top, taking excess energy & entropy with them (evaporative cooling), and the remaining atoms rethermalize at a lower temperature.

      Once a significant number of atoms fall into the ground state of the SHO, the rest quickly follow, as the probability of scattering into a given state greatly increases with the number of atoms in that state. (this is entirely analogous to photons in a laser all precipitating into the same state, for the same reasons, forming a coherent beam. And it only occurs for atoms which are bosonic, ie those for which #p + #n + #e = even)

    4. Re:Missing some info here by DavidTC · · Score: 3, Interesting
      Ha, no, they recently got fermionic atoms to form a BEC. ;)

      I know, it's a trick. The fermionic atoms pair up. Weird trick, I don't really get it. (How are they overlapping enough do that in the first place? Damn quantum mechanics.)

      So, more technically, it only occurs for entities which are bosonic.

      But that way leads to madness and people walking though walls after removing a few atoms from their body and the wall.

      --
      If corporations are people, aren't stockholders guilty of slavery?
  14. I'm not sure this is that new by bombastinator · · Score: 4, Interesting

    I remember either Porsche or Volkswagen having a limited slip clutch that consisted of two perforated disks set next to each other in a container of special goo. If the wheels slipped it caused the disks to rotate at different speeds and the friction caused enough heat to turn the goo solid. I can't remember why they quit using it but it was more than a few years ago. I think it was going into their 4 wheel drive race cars. Just a memory though I got no hard data. Anyone know more about this?

    1. Re:I'm not sure this is that new by HenryKoren · · Score: 4, Informative
      You are refering to the All Wheel Drive system produced for the VW Audi Group by Haldex

      From Haldex:

      The unit can be viewed as a hydraulic pump in which the housing and an annular piston are connected to one shaft and a piston actuator is connected to the other.

      The two shafts are connected via the wet multi-plate clutch pack, normally unloaded and thus transferring no torque between the shafts.

      When both shafts are rotating at the same speed, there is no pumping action. When a speed difference occurs, the pumping starts immediately to generate oil flow. It is a piston pump, so there is a virtually instant reaction with no low-speed pumping loss.

      The oil flows to a clutch piston, compressing the clutch pack and braking the speed difference between the axles. The oil returns to the reservoir via a controllable valve, which adjusts the oil pressure and the force on the clutch package.

      Something tells me having hydralic fluid that turns solid when it gets hot wouldn't help a system like this :-)
    2. Re:I'm not sure this is that new by Afrosheen · · Score: 4, Informative

      You're talking about a standard 'wet' limited slip differential, or LSD. Wet LSD's have a viscous solution inside that, as the spider gears generate friction by spinning opposite directions, solidifies to unify power delivery from the driveshaft. An open differential allows wheels to spin at differing speeds, usually giving more power to the wheel that's spinning more freely. This is bad in racing. It's also bad for 4wd cars like the Subaru WRX or the Mitsubishi Evolution VIII. Both cars have LSD standard.

      The other type of LSD is a clutch-plate type. These can be adjusted for resistance to slippage by arranging the type and order of clutch plates in the LSD. A viscous LSD on the other hand is governed by the properties of the fluid, and is subject to failure under high loads (i.e. the liquid can only take so much friction before it breaks down and loses it's valuable properties). In general practice, for performance and cost, viscous LSD's are used, but for high performance, resilience, adjustability and durability, the clutch type LSD is preferable, but has a significantly higher cost.

      That's about all I know about LSD's.

    3. Re:I'm not sure this is that new by brer_rabbit · · Score: 3, Funny

      so next time I'm at the car dealership, I should inquire if the car comes with LSD, and if so, what sort of LSD it uses? I've been told to avoid the brown LSD.

  15. Breaks the laws of physics? by mike_lynn · · Score: 4, Informative

    Which law would this be? The one that says solids melt into liquids at higher temperatures? Oh wait, there is no such law - thanks to something called Sublimiation where solids go straight to a gas (like dry ice).

    This is not an example of a new found element with impossible thermal properties. This is an example of materials and molecular chemistry in action. This works because it follows the laws of physics.

  16. Space shuttle? by Bin_jammin · · Score: 3, Interesting

    I wonder if it would be possible to change the temperature at which it re-liquifies, and if it becomes harder or more dense at higher temperatures. Seems like if that were the case, it would make for a good tiling material for the skin of a space shuttle

  17. Roland Piquepaille by Mr2cents · · Score: 4, Funny

    I vote for a new "Roland Piquepaille" section, he should get a good amount of advertisement revenue from his daily submits, always with "read more" links just quoting the original story.

    --
    "It's too bad that stupidity isn't painful." - Anton LaVey
  18. I don't know chemistry by Anonymous+Writer · · Score: 4, Funny

    Plazanet and colleagues prepared a liquid solution containing ?-cyclodextrine (?CD), water and 4-methylpyridine (4MP).

    Is it edible?

    1. Re:I don't know chemistry by k98sven · · Score: 4, Informative

      cyclodextrin? Probably. It's starch.

      water? Definitely.

      4-methylpyridine? Probably causes cancer. Known to cause damage to the central nervous system. In simple words: Poision.

  19. Damnable Hydrogen Bonds by softspokenrevolution · · Score: 3, Funny

    Damn you hydrogen bonding, damn you shaking up our worlds with your heat freezing solids.

  20. New meaning to the term lock up by Duct+Tape+Pro · · Score: 3, Interesting

    I sure hope it's non-conductive so I can put it as a coolant in my computer. Computer gets too hot, it turns solid and the computer "locks up". Ha!

    Seriously though, if this stuff interacts well with other substances (i.e. doesn't explode, melt, send it to another dimension) then it could feasibly have applications where it would solidify around objects once they got too hot, thereby stopping their motion. And since the article says you can adjust the solidifying (freezing?) point based on its concentration, it could be tailor-made for different devices. This probably won't happen though because I'm guessing this stuff is probably expensive to make and does who-knows-what to human tissue

    --
    i hotdog.
  21. Re:Application: Construction of Skyscrapers by John+Courtland · · Score: 4, Insightful

    Not that I can read the article yet (due to slowness), but the summary doesn't say what happens after 75C. It might melt again and that would be bad. If true, this chemical will possibly force the scientific community to reevaluate chemical laws and make new, more general (and therefore better) ones.

    --
    Slashdot is proof that Sturgeon's Law applies to mankind.
  22. Useful material to have when printing out organs by Billy+the+Mountain · · Score: 5, Interesting

    This article describes a similar material that is liquid below 20 C and solid above 32 C. Medical researchers hope to use it if they are able to perfect 3D printers that generate organs by spraying cells onto a substrate. The gel is used to reserve open spaces for blood vessels. Once the organ has been formed they cool it and the solid turns to liquid and runs out.

    BTM

    --
    That was the turning point of my life--I went from negative zero to positive zero.
  23. Breaks the rules? by Epsillon · · Score: 3, Informative

    The rules of freezing, melting and vaporising (yes, I missed out sublimation) are not broken here. Chemists have known for some time that certain reactions can both only take place at a certain range of temperatures and reverse outside that range. This stuff does not freeze. It simply undergoes a reaction which bonds two types of molecule together to form a cohesive structure. The "normal" rules still apply to both compounds, but the new compound has a higher freezing point. That the reaction to form the new compound is reversible is also nothing new.

    Analogy: Water freezes at 0 degrees Celsius, sodium chloride (salt) much higher at 804 Celsius. Add the two together to form an aqueous solution of sodium chloride and it lowers the freezing temperature, contrary to the properties of both substances. Heat it, and evaporate the water off and you end up with solid NaCl.

    Sorry, but this has been hyped beyond recognition.

    --
    Resistance is futile. Reactance buggers it up.
  24. Astroturf Alert! by Gothmolly · · Score: 3, Informative

    Warning, this Roland fellow submits (and they get accepted!) stories all the time, which link to his personal blog site. All his posts have the same format. Stop feeding him page views!

    --
    I want to delete my account but Slashdot doesn't allow it.
  25. Re:Application: Construction of Skyscrapers by mtnharo · · Score: 4, Informative
    An interesting concept, but I think we would need to research it a bit more. From what I gather in the article, the solution turns solid when heated between 45-75C. Beyond that it probably either burns or melts again. Those temps are much too low to have any impact in a fire.

    Secondly, based on the types of compounds in the solution, and the description in the article, the "solid" is probably more of a waxy/jelly sort of substance.

    That said, your idea could be made to work in other cases. I wonder if maybe the substance could be altered for use as a variable damping material for suspension or acoustic purposes.

  26. Re:Cool by k98sven · · Score: 4, Informative

    Can someone explain the phrase 'sol-gel'? Does that mean that it become more like a gelatinous subject when heated instead of a more 'solid' solid?

    Sols aren't solids. A "sol" is a colloid solution, so is a gel. Without getting too deep into the chemistry, he's basically saying it's a gel.

    (Look up 'sol', 'gel', 'dispersion' and 'colloid' for more details)

  27. Re:Application: Construction of Skyscrapers by Exitthree · · Score: 4, Interesting

    First, the World Trade Center collapsed because jet fuel burns extremely hot. The WTC design was actually far stronger than most other skyscrapers standing today. Notice that the building survived the initial impact of a plane, and that it wasn't until later, when the intense heat of the burning fuel had time to weaken the steel support structure that it collapsed. A normal building fire would not have threatened the structural integrity of the WTC because there was nothing in the WTC that was hot enough to melt the beams, until the plane, full of fuel, arrived.

    Second, I didn't notice in the article whether the volume of the material expands or contracts when it turns solid. If the hollow beam is partly filled with liquid (because the liquid expands when frozen) then there isn't necessarily enough contact between the liquid and the burning sections of the building to protect the upper portions of the beam. The beam will conduct some of the heat to the liquid, but depending on where the fire occurs in relation to the beam, the top of the liquid might freeze first, leaving the upper portion of the beam hollow. If the liquid contracts when frozen, you end up with a partly filled beam, which isn't necessarily stronger than a beam with nothing in it.

    This leads to the third point, that nothing is mentioned about the structural properties of the liquid when frozen. Steel behaves extremely well under tension, and concrete under pressure. Thus, they complement each other quite well (which is why we make buildings out of them). Would the liquid make a better replacement for the steel, or the concrete? And would it perform equally well when the building is not on fire? Has having liquid-filled cavities in the building strengthened or weakened the structure, for the large majority of the time?

    Finally, does the cost of using a material like this justify it? It's new, it probably costs more than steel to use in a building. Wouldn't redundant support structures be more reasonable? Or, using a design like the WTC, which I noted only failed from the heat of burning jet fuel?

  28. liquid bullet proof jackets anyone? by Goeland86 · · Score: 3, Interesting

    I remember reading somewhere about making a bullet proof suit for soldiers where the suit was in fact hollow and filled with a gel containing nanoparticles. This thing might help us make more efficient ones: when the bullet hits the gel, the pressure is going to make it increase in heat, isn't it? So as the bullet tries to penetrate, it's going to get harder and harder... thus absorbing a HUGE amount of energy. Once the bullet is fully stopped, the pressure disappears, the temperature goes back down to normal and you have a liquid armor again. One problem is keeping the liquid from spilling out of the holes the bullets make... But I'm quite confident that can be overcome with some brilliant imagination. Of course, the real problem is how breakable is the solid formed? Because if the bullet goes straight through the hard material, then there's not point. But I think that'd be one use of this...

    --
    ---- I am certain of only one thing : I know nothing else.
  29. Re:Cool by Medevo · · Score: 4, Interesting

    Check out http://www.solgel.com/educational/glossary.htm/ and http://www.chemat.com/html/solgel.html/

    Its basically a more refined process of distilling out a liquid from a solution, and getting a solid out. However this new solid has chemical properties of both parts of whatever was in the solution. It allows for things like low-temperature glassmaking.

    Literally a "sol-gel" is just a solid that still has some of the properties of a liquid/fluid such as flowing and free atomic relocation, but is much closer to a solid then a traditional fluid. This however does not make it a "jelly" or a "gel" its chemically, as well as physically distinct.

    Medevo

  30. "dumb-it-down" soundbite phrasing by Space+cowboy · · Score: 4, Insightful

    It doesn't break any law, it follows every law. Physics around phase-changes (liquid-solid, gas-liquid, gas-solid) can be really weird. Iodine sublimes (goes from solid crystal form to gas with no intermediate liquid form) for example, at least at STP.

    It's almost certainly those pesky hydrogen bonds - they're responsible for just about everything interesting in organic chemistry... Strange how things ultimately come down to geometry :-)

    It is new and strange, but I'd be willing to bet just about anything that the physical laws of energy conservation, attraction and conversion are being rigorously adhered to :-))

    Simon

    --
    Physicists get Hadrons!
  31. Useful for cooling stuff. by gnalle · · Score: 4, Informative
    When the liquid melts, the heat of melting is taken from the vibrational energy, and thus the liquid is cooled by melting. I guess that this positive feedback mechanism would enable the liquid to melt fast whenever it is cooled below the melting point, and thus the new liquid should be very effective for cooling stuff very fast.

    To a physicist the phase diagram is interesting, because the solid/gel must have a larger entropy than the corresponding liquid. (Remember that you calculate equilibrium by minimizing the Gibbs energy G = H - TS).

    Anyway it has been known for many years that some triblock polymers form gels when heated, but perhaps the solid phase of this new liquid is "more solid". Perhaps the news is that the liquid has a larger enthalpy of melting. I don't know

  32. Summary for non-chemists by k98sven · · Score: 4, Insightful

    After reading the article (the actual publication, that is), here's an attempt at a summary.

    When you heat something, the entropy (disorder) of a system increases in importance. This is a law of thermodynamics.

    A gas has greater entropy than a liquid, both have greater entropy than a solid. Usually.

    Now, this substance turns solid when you heat it. -This means the solid phase has higher entropy than the liquid phase. That is unusual, but it doesn't violate any laws.

    How does it work? Well, it appear the alpha-cyclodextrin molecule has two conformations (shapes). In the low-temperature one, it hydrogen-bonds to itself. At higher temperatures, these bonds are broken. (this is what happens with ice-water-steam too)

    The funny thing about this substance, is that once these internal hydrogen bonds are broken, it allows the molecule to bind to other ones.. so while you break the "internal" hydrogen bonds, you give rise to a bunch of "external" molecular bonds, to other alpha-cyclodextrine molecules.

    This leads to the formation of a solid. (not actually a true solid, but rather a 'sol', a suspension of linked-together alpha-Cyclodextrin molecules in water) And this solid actually does have lower entropy than the liquid phase, due to the breaking of the internal hydrogen-bonds.

    No laws broken. Nothing 'impossible' going on. But, it is however an interesting phenomenon, and something which certainly may turn out to have practical uses in the future.

  33. Ok, here's what I can come up with by Weaselmancer · · Score: 4, Insightful

    Shock absorbers. This stuff would make fantastic shock absorbers.

    Reinforcement for solid structures. Somebody already mentioned skyscrapers, but I'm also envisoning other more improbable structures, like hurricaine proof buildings. Wind blows, soften up the beams and let her bend a bit. Wind stops, stiffen the supports back up.

    Mecha. This has to be used in mecha. Beams that can bend a bit, be solid or fluid, would be excellent in 50 foot killer robots. You know it.

    Tank armour. Make it solid and when stuff hits, it breaks. Change temperature, and it melts. Change temp again and it becomes solid again, with no signs of previous damage. Regenerating armour.

    --
    Weaselmancer
    rediculous.
  34. Is this really news? by cyclop · · Score: 3, Insightful

    Well,it's amazing, but it's not the first time i see it.

    I work in molecular biology. Recently we started doing experiments with so-called Matrigel. This is purified extracellular matrix from mice tumours. It's a natural environment to grow endothelial cells and study the development of blood vessels. This is by no means a mysterious substance - thousand of labs buy it and use it every day.

    Well, Matrigel works exactly the same way the substance in the article does. It is fluid around 0, but rapidly freezes at -20 and rapidly becomes solid at room temperature. And it is fully reversible. This also makes the substance a bitch to manipulate -you pick up with the pipette,and it becomes solid inside the pipette before you can transfer it!

    Still, it is amazing to mimic such a behaviour in a simple solution instead than in the tremendous proteins-and-sugars mess that's Matrigel.

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    -- Patent no.123456: A way to personalize /. comments with a sig attached to the end.
  35. Torsen differential by wotevah · · Score: 3, Informative

    The best option over the above (and a common upgrade) is the fully-mechanical "Torsen" ( torque-sensing ) differential.

    Quaife makes one of these. An all-wheel drive car would need three, and at around $1k a pop they aren't exactly cheap, but they have a lifetime warranty.

  36. New deodorant? by bscott · · Score: 4, Funny

    "Body heat activated - when the temperature rises, it fuses your arms to your sides so that you can't release any bad armpit smells"

    OK, I'm just spitballing here.

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    Perfectly Normal Industries
  37. Re:Application: Construction of Skyscrapers by wash23 · · Score: 5, Informative

    It most certainly would melt again after 75C; it's just a hydrogen-bonded organic solid at that point, and hydrogen bonds are weak and only partially-covalent and would easily melt at moderate temperatures.

  38. Re:Application: Construction of Skyscrapers by Alsee · · Score: 4, Insightful

    hot enough to melt the beams

    Even with jet fuel it wasn't enough to melt the steel. The problem is that steel loses much of it's strength at high temperatures, making it liable to bend or snap under load.

    Also, and I relize your are replying to someone else's idea here, but I fail to see any logic in using this stuff in construction. What possible benefit is there in having the material be liquid at low temperatures? Instead of adding this stuff "in case of fire" you're better off using some ordinary building material that will be stronger at both low and high temperatures.

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    - - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
  39. Slashdot Egoists + science story = hilarity by Bill,+Shooter+of+Bul · · Score: 4, Interesting

    Every one at slashdot thinks they understand science because they think of themselves as geeks. I say it is not being a geek that makes you a scientist, but being a scientist makes you a geek. This story is a perfect example. Some material does something that we would not expect based upon our own observational experience, but since we "know science" it must violate all of our accepted scientific ideas. Its really funny if you don't take it serious. Seriously it must show that our educational system has doen such a poor job of explaining the basics of the scientific process and/or that we'd rather make fools of ourselves than admit that we don't know everything.

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    Well.. maybe. Or Maybe not. But Definitely not sort of.