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Chemical Reaction Changes Color Over and Over

Posted by timothy on from the note-gratuitous-but-accurate-dig dept.

DancingFountain writes "If you have taken a college chemistry class, you may have seen this fantastic demonstration. When two clear liquids are mixed, they immediately turn yellow, and then undulate back and forth between blue-black and yellow in a mesmerizing display. Wired Science explains that the reaction, which was developed by two high school science teachers, has been rigorously studied but not fully explained."

61 comments

  1. Digg? by tsa · · Score: 0, Troll

    I thought I had removed my bookmark to Digg.

    --

    -- Cheers!

  2. the 'insert your politician name' effect by peter303 · · Score: 2, Insightful

    During this period when half of those running for office are being accused of changing their mind every 15 minutes, I expect many of these jokes to be posted.

    1. Re:the 'insert your politician name' effect by Bongo+Bill · · Score: 1

      So... the Clinton effect? No, wait, the Huckabee effect! No, maybe it's....

      --
      ...but is it art?
  3. Huh? by moosesocks · · Score: 3, Interesting

    I'm confused..... where's the news here?

    The reaction's notable for its cyclical nature and the fact that we don't really understand the underlying mechanisms. According to the news article, we still haven't figured it out.

    Thanks for that status update!

    --
    -- If you try to fail and succeed, which have you done? - Uli's moose
    1. Re:Huh? by bruins01 · · Score: 1

      A better question is WHEN is the news here? And the answer to that is 1973.

    2. Re:Huh? by snowraver1 · · Score: 1

      "You're not thinking fourth dimentionally" - Dr. Emmett Brown

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      Copyright 2010. All rights reserved. This comment may not be copied in any way including, but not limited to caching.
    3. Re:Huh? by SQLGuru · · Score: 1, Funny

      So, can you use this knowledge to make perpetual motion machine? From what I remember of my chemistry (granted, I only got a C and it was quite a few years ago), but chemical reactions give off heat.....and heat can be used to generate power.

      http://en.wikipedia.org/wiki/Perpetual_motion

      Layne

    4. Re:Huh? by The+One+and+Only · · Score: 2, Insightful

      Perpetual motion is impossible. Fundamentally. Furthermore, some chemical reactions take in heat instead of giving it off. But back to the main point, perpetual motion contradicts the second law of thermodynamics, and as a consequence, if perpetual motion machines did exist, almost everything we know about physics would be wrong.

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      In Repressive Burma, it's not just your connection that dies. slashdot.org/comments.pl?sid=314547&cid=20819199
    5. Re:Huh? by MicktheMech · · Score: 2, Insightful

      No.

      In fact, that's the answer to all questions of the form "So, can you use X to make a perpetual motion machine?".

    6. Re:Huh? by moosesocks · · Score: 4, Informative

      Uhm. No.

      Perpetual motion machines are flat-out impossible. Conservation of energy is a *VERY* well established scientific fact.

      Chemical reactions don't necessarily release heat. Endothermic reactions tend to absorb it. The reaction mechanism here just happens to end up with a large amount of its original reactants at the end, and most likely catalyzes itself somewhere along the way.

      The reaction in question isn't exactly perpetual either. The system eventually reaches equilibrium, and the cycle stops. (Entropy -- another well-established scientific principle makes perpetual motion rather unlikely)

      If you wanted to harvest energy from the reaction, you'd have to directly absorb it from the system as the reaction is taking place. This alters the system, and will most likely result in the reaction stopping, assuming that the temperature differential is great enough to allow you to harvest any useful amount of energy (I don't recall this particular reaction getting very hot, so that seems unlikely). You'd also be limited by the second law of thermodynamics and the carnot efficency probably wouldn't be all that favorable.

      So, all in all, the reaction's rather novel, although there's nothing in our current understanding of scientific fact that dictates that it should be impossible, even though we haven't been able to piece together the exact mechanism by which the reaction actually takes place.

      --
      -- If you try to fail and succeed, which have you done? - Uli's moose
    7. Re:Huh? by Jugalator · · Score: 1

      I agree, this one could just as well have been a link to the YouTube video, because the actual story here is the spectacular effect, not what they know, or rather don't know. :-)

      --
      Beware: In C++, your friends can see your privates!
    8. Re:Huh? by Bandman · · Score: 1, Insightful

      The magnetic stirrer under the glass doesn't run on pixie dust...

      --
      Check out my sysadmin blog!
    9. Re:Huh? by nomel · · Score: 1

      This same type of reaction was shown on Mr. Wizard when I was a kid!
      In his, a pH indicator was added to a solution and it would go back and fourth between acidic and basic...can't remember the cause, but he explained it just fine. I think it had to do with the creation of crystals in the solution, which is why it had to be continually mixed. Could say I have a bad memory, but that was about 15 years ago.

    10. Re:Huh? by Mr2cents · · Score: 3, Informative

      The wired article itself does not provide much information, but one of its' links, more specifically this one explains a lot (including the reactions). It does say that is does not go on for ever, but repeats for "just" 15 cycles or more. It would have been cool if it went on forever, but no such luck.

      --
      "It's too bad that stupidity isn't painful." - Anton LaVey
    11. Re:Huh? by Anonymous Coward · · Score: 1, Insightful

      But back to the main point, perpetual motion contradicts the second law of thermodynamics,...

      Maybe.

      Perpetual motion machines get classified on the basis of whether they claim to violate the first law of thermodynamics (conservation of energy) or the second law of thermodynamics (limits on converting heat to other forms of energy). Whether it would be possible to have a perpetual motion machine that only violated the first law, but not the second law, is a tricky question because the first law is so fundamental to our understanding of physics (including our understanding of the second law).

      ...and as a consequence, if perpetual motion machines did exist, almost everything we know about physics would be wrong.

      Not necessarily.

      In the first place, physics has yet to develop a "Theory of Everything", (e.g. integrating the general relativity view on gravity with the quantum field theory view on forces between sub-atomic particles). Since there isn't yet a theory that "explains it all", it would be hard to come up with any experimental observation contradicted that theory.

      Second, it's important to distinguish between violations of the first law and violations of the second law.

      In the case of the first law, conservation of energy is, admittedly, pretty fundamental to the formulation of the basic laws of physics. On the other hand, suppose experimental physicists were to discover a new sub-atomic particle that continuously emitted photons. Naturally, that would require some reworking of the standard model but many of the higher level theories might well survive largely unchanged. For example, the behavior of an electron would still be accurately described by the Schrodinger equation.

      In the case of the second law, the effect on established physical theories might be even smaller. Suppose, for example, scientists discovered a particular material that developed a permanent voltage gradient across it in the presence of a strong (static) magnetic field. As long as the material got colder when the voltage gradient was used to drive a current, conservation of energy (the first law) would still be valid. The only modification that would be needed to physics would be to state that the second law applies to everything except this particular material - not really a big change.

      Anyway, getting back to the original question of whether this particular reaction constitutes perpetual motion, unfortunately the answer is "no". What's happening is that the reaction inhibits itself (a negative feedback loop). The reaction starts going but produces some stuff that causes the reaction to stop but then the stuff that stopped the reaction gets neutralized and the reaction can start going again - but then the reaction produces some stuff that causes it to stop again, etc.

    12. Re:Huh? by Zaurus · · Score: 4, Funny

      Perpetual motion machines are flat-out impossible. ...unless you're raising a toddler.
    13. Re:Huh? by fireboy1919 · · Score: 3, Insightful

      Conservation of energy is a *VERY* well established scientific fact.

      No. Conservation is a law - a postulate. Something that we're extremely certain that can't prove using other laws, but that has never, ever been wrong once. That is the fact. If we found something that violated this law, then it would no longer be considered a law. Personally, I don't consider overwhelming evidence that something has always happened a particular way within the observation of man proof that it always did or always will. Don't get me wrong: I'd never take a bet that a perpetual motion machine is going to work, but I'm not going to go around believing that reality is 100% certain to work the way that I think it does, either.

      The system eventually reaches equilibrium, and the cycle stop

      Apparently goes through about 10 cycles, according to Wikipedia.

      --
      Mod me down and I will become more powerful than you can possibly imagine!
    14. Re:Huh? by paintballer1087 · · Score: 3, Interesting

      And that's impossible. I mean science has always gotten everything right about physics. Don't belive those crazy rumors going around that the world is spherical.... As much as we know about physics, astronomy, matter, time, space, etc... There's that much more that we don't know. I'm not saying perpetual motion is something that will ever be discovered, or if it is possible. But saying something is "impossible" because we would be wrong otherwise, puts us at the place of knowing everything. As far as we know, the second law of thermodynamics is right, but we've been proven wrong in the past, and probably will in the future.

    15. Re:Huh? by complete+loony · · Score: 1

      It doesn't go on forever.

      The reaction is always consuming IO3-, acid and hydrogen peroxide to produce ICH(COOH)2, water and oxygen. However there are a number of different reactions going on at different rates with different catalysts that change the concentrations of I-, HIO, HIO2 and I2.

      High concentrations of I2 by itself looks amber. High I2 and I- with starch turns blue / black. As the I2 is consumed the solution becomes clear.

      --
      09F91102 no, 455FE104 nope, F190A1E8 uh-uh, 7A5F8A09 that's not it, C87294CE no. Ah! 452F6E403CDF10714E41DFAA257D313F.
    16. Re:Huh? by Anonymous Coward · · Score: 0

      On the other hand, suppose experimental physicists were to discover a new sub-atomic particle that continuously emitted photons. Bad example. Any particle affected by the electromagnetic force emits (and absorbs) photons all the time as the force carrier. That's what photons are for.
    17. Re:Huh? by The+One+and+Only · · Score: 2, Interesting

      I was going to expand my thoughts by sharing Quine's views on knowledge, but I thought it would be total overkill. But since you brought it up--Quine teaches us that we all hold a body of beliefs that are consistent with each other, and that any given belief has more or less credence to us based upon evidence (i.e. the other beliefs within the system) and the need to make the system itself consistent. So if I am investigating a murder, and believe that one of three men committed the murder, I investigate each of them and ask for an alibi. If all three of them give me an alibi and it's corroborated, I have to decide: which one of them is lying? Or perhaps did some fourth person commit the murder? I have to toss out one belief so the others fit. (And if I really wanted to, I could hold on to any belief, just as long as I adjust the others to fit. This is what conspiracy theorists do. But that's not very practical, so Quine advises us not to do that.)

      The same process occurs in science. When we find something that seems like a perpetual motion machine, we have to either believe that it isn't a perpetual motion machine, or that the laws of thermodynamics are wrong. Given how much we have invested in the laws of thermodynamics, it's usually easier to give more credence to the notion that the alleged perpetual motion machine isn't. Now, if we had enough evidence that a supposed machine was capable of perpetual motion, then we would overturn the laws of thermodynamics. But it would take a great deal.

      --
      In Repressive Burma, it's not just your connection that dies. slashdot.org/comments.pl?sid=314547&cid=20819199
    18. Re:Huh? by Anonymous Coward · · Score: 0

      /. is a blog....

    19. Re:Huh? by Anonymous Coward · · Score: 0

      or maybe it's just because WIRED decided it needed attention. Who cares, it's mesmerizing!

    20. Re:Huh? by Lehk228 · · Score: 2, Funny

      go ahead and stop feeding him, the motions will stop in a few days.

      --
      Snowden and Manning are heroes.
    21. Re:Huh? by ceoyoyo · · Score: 3, Funny

      That's not perpetual motion. Have you noticed you're more tired since you had him? The energy has to come from somewhere you see. It just seems really impressive because you're big and he's little so when you put your energy in a little package it moves much faster.

    22. Re:Huh? by Zencyde · · Score: 1

      I don't like doing this; but, you misspelled dimensionally. You are obviously not running Firefox or Linux. I am hereby revoking your geek card. You may reapply for it in six months.

      --
      What day is it? Could you please tell me?
    23. Re:Huh? by jotok · · Score: 1

      Not well understood? I wouldn't say so. This and similar reactions are covered in (among other works) Goodwin's How the Leopard Changed Its Spots.

      I mean, is anything really perfectly understood? Probably not, but I think these are well-characterized.

    24. Re:Huh? by Thanshin · · Score: 1

      You may reapply for it in six months. You'll find more news about your reappliance results in slashdot, day 10/12/2024
    25. Re:Huh? by Tastecicles · · Score: 1

      Perpetual motion machines are flat-out impossible.

      You're not a parent, are you?

      --
      Operation Guillotine is in effect.
    26. Re:Huh? by Anonymous Coward · · Score: 0

      I had a good laugh at this.

      Thought I'd mention that according to Dave Barry, intelligence also transfers from parent to child. This becomes very pronounced as the child enters the teen years and they increasingly realize they are becoming much smarter than their parents. The parents stupidity about curfew, the ability to safely operate motor vehicles, and whether parties with alcohol and no adult supervision are wholesome, stimulating environments becomes epidemic at as the child enters the latter years of high school.

    27. Re:Huh? by Anonymous Coward · · Score: 0

      On the other hand, suppose experimental physicists were to discover a new sub-atomic particle that continuously emitted photons.
      Bad example. Any particle affected by the electromagnetic force emits (and absorbs) photons all the time as the force carrier. That's what photons are for.

      Hmmm, interesting point.

      Well, I was referring to the emission of real photons as opposed to virtual photons but the conservation laws can look pretty strange - just take the Unruh effect, for example.

  4. Just had to slip one in? by techpawn · · Score: 2, Funny

    Like Mitt Romney speaking on social issues, the undulating brew just can't make up its mind.
    did they HAVE to take a political jab in the science blog?
    --
    Ask not what you can do for your country. Ask what your country did to you
    1. Re:Just had to slip one in? by rk · · Score: 1

      Well, politicians are well known for sticking their noses into anything and everything, so I suppose turnabout is fair play.

    2. Re:Just had to slip one in? by framauro13 · · Score: 5, Funny

      It's ok. Republican's don't believe in science. He'll never read this.

      --
      In an effort to conform with internet communication standards, please note that the above comment is 100% biased opinion
    3. Re:Just had to slip one in? by Anonymous Coward · · Score: 0

      Yes, the whole article is just an excuse for this cheap shot. Buried. Ooops, this isn't digg.

    4. Re:Just had to slip one in? by Digi-John · · Score: 2, Informative
      It's ok. Republican's don't believe in science. He'll never read this.

      Apparently Democrats don't believe in grammar? Oh, and if you're actually Green Party or Socialist, I apologize--I swear I'll mock you just as much as you deserve as soon as I get the chance. I'm just really busy right now; you know how it gets with work and all that... unless you're a Socialist, in which case you're probably late for your Art History 233 class.

      --
      Klingon programs don't timeshare, they battle for supremacy.
    5. Re:Just had to slip one in? by framauro13 · · Score: 0
      I'd prefer to think of myself as an independent. You know, someone who's intelligent enough to make a decision on their own without needing a politcal party to tell them what to think? I made a typing mistake. If I was in fact a Republican, I'd convince everyone MY grammar was correct and all the 'liberal academics' were brain-washing the public with false grammar and facts in books. Good job exposing my flaws to the world. That'll teach me!

      Besides, it was a joke. Relax. Go get laid or something.

      unless you're a Socialist, in which case you're probably late for your Art History 233 class. Typical Republican response. "If you're not with us, you're Socialist." Very creative and original. You guys have had your time. Nice job fucking up the country over the last 7 years. Brilliantly executed.

      Oh, and sorry, I'm college educated with industry certifications. Besides, I never passed Art History 210, so I wasn't allowed into Art History 233.

      Nice try though.

      Ok, that's the end of my rant. Back to the subject at hand...
      --
      In an effort to conform with internet communication standards, please note that the above comment is 100% biased opinion
  5. i remember this from high school by circletimessquare · · Score: 4, Informative

    it has to do with the fact that instead of the usual equilibrium present in a reaction, there are two, or three equilibriums between three or four different states, all roughly equivalent thermodynamically. they just seesaw around in circles between the equilibriums when a little energy is introduced into the mix. apparently its very tricky to get it just right. but if you do, the equilbriums bounce back and forth between each other like a pendulum or spring, and sometimes, balanced just right, like a pendulum on a grandfather clock, they can bounce back and forth for a very long time

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    1. Re:i remember this from high school by SpaceLifeForm · · Score: 1

      I recall this also. I don't recall the chemicals used,
      but the solution oscillated between purple and clear,
      eventually ending purple.

      --
      You are being MICROattacked, from various angles, in a SOFT manner.
    2. Re:i remember this from high school by Bandman · · Score: 1

      I hate to nag, but the pendulum on a grandfather clock doesn't stop due to the weights hanging on it, which turn a wheel, whi..nevermind. It's just cause of the weights at the bottom.

      --
      Check out my sysadmin blog!
    3. Re:i remember this from high school by tgd · · Score: 1

      Um, what?

      It stops because of friction in the mechanism. No friction, it would keep going forever.

    4. Re:i remember this from high school by Anonymous Coward · · Score: 0

      no seriously, he's right. There are weights that dangle and turn a wheel(gears etc) and the pendulum motion comes from that. I used to have to reset the weights on my families clock weekly. It's not like you just start the pendulum swinging with a good solid smack and wait til it stops moving because of friction. Seriously if you don't know the technology don't make assumptions, analog isn't that simple.

    5. Re:i remember this from high school by Anonymous Coward · · Score: 0
      No friction, it would keep going forever.

      True (or close enough), but nevertheless a horribly flawed argument. Just because, in the absence of friction, the pendulum would swing "forever," does not mean that, in the presence of friction, the pendulum would swing for any appreciable amount of time. A clock relying solely on such a pendulum would not be very useful unless you need to measure the passage of only a few minutes (and not very reliable minutes) at a time. Hence the weights mentioned by the other posters.

  6. It's the formula for the Steelers Defense! by TrebleJunkie · · Score: 0, Flamebait

    Black, then Gold, then clear sailing through to the end zone!

    --

    Ed R.Zahurak

    You know, oblivion keeps looking better every day.

  7. Looks cool by snarfies · · Score: 1

    While it looks cool, its not exactly news, is it? When I was in 4th grade I had a Hypercolor shirt that did the same thing. That was like... 1986?

  8. Iodine Clock Reaction by Anonymous Coward · · Score: 1, Interesting

    I know some people hate Wikipedia, but it has far more useful information, than this silly "article" has.

    1. Re:Iodine Clock Reaction by $RANDOMLUSER · · Score: 2, Informative

      Actually, it's this reaction TFA is talking about.

      --
      No folly is more costly than the folly of intolerant idealism. - Winston Churchill
    2. Re:Iodine Clock Reaction by $RANDOMLUSER · · Score: 1

      Mumble. Blew the link.

      --
      No folly is more costly than the folly of intolerant idealism. - Winston Churchill
  9. Instructions by tirerim · · Score: 1

    If anyone wants to know how to do this for themselves (well, assuming you can find all the components), here are some instructions.

  10. WHAT ... is your favorite colour? by Colin+Douglas+Howell · · Score: 3, Funny

    Yellow. No, blue--AAAAAAAAHHH!

    [Too bad the movie has the colors in the opposite order.]

  11. Should use the standard politician instead by Anonymous Coward · · Score: 0

    I believe John Kerry is the standard for repeatedly switching sides,

    whereas Bill Clinton is the standard for being on both sides of an issue simultaneously.

    1. Re:Should use the standard politician instead by Anonymous Coward · · Score: 0

      I tend to take the opposite stance of whoever I'm talking to. I'm well aware of the flaws in the arguments of both sides of every dispute so I can't help but stir up an argument any time I see someone playing partisan.

      Not adhering to dogma is a good thing. Changing your mind when presented with new evidence is a good thing. But opportunistically adopting a new position when it is convenient is a bad thing. There is nothing I despise more than someone who takes a calculated stance rather than a heartfelt one. It's what makes me hate Clinton and Romney.

  12. Direct Video Link by Erioll · · Score: 3, Informative

    Here's a video of it on google video: http://video.google.com/videoplay?docid=680106771263243162

  13. News from before you were born. by siglercm · · Score: 3, Funny

    I knew I had seen something like this in an article I read... THIRTY YEARS AGO...

    http://amasci.com/amateur/sciamdx.html

    Search for "Chemical reactions, oscillating".

    Sorry, kiddies. Been there, done that. Still interesting, though.

    --
    sigfault (core dumped)
  14. Re:Huh? Umm, maybe it's a... by davidsyes · · Score: 1

    Reactionary "collide-o-scope"?

    --
    Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
  15. This is just another BZ-like system... by Anonymous Coward · · Score: 0

    This is very similar to a BZ reaction (a simple pH oscillator) which has been known for more than 40 years. http://en.wikipedia.org/wiki/BZ_reaction It is an example of a "far from equilibrium" system. While the entire kinetic mechanism is probably unknown (because there can be 1000's of reactions) the general mechanism behind oscillatory systems is largely known.

    This oscillation will proceed indefinitely until one of the reactants is completely consumed. This does not violate the laws of thermodynamics since the free energy of the system is ALWAYS decreasing towards zero (thus approaching its equilibrium state). It is simply doing it in a nonlinear way. Thermodynamics only tells us what the final state of the system will be, it says nothing about how the system reaches it. (This is the domain of chemical kinetics)

    I knew one day my Chem. Eng. PhD research would come in handy!

  16. Dig out your chemistry set... by HotNeedleOfInquiry · · Score: 2, Informative

    Here's the procedure for demonstrating the reaction

    http://www.chem.leeds.ac.uk/delights/texts/expt_11.html

    --
    "Eve of Destruction", it's not just for old hippies anymore...
  17. Hey! I Know Them... by Talkischeap · · Score: 1

    Cool!

    Warren & Tom make Slash Dot.

    I know them from the international Caving community, where they are well regarded.

    Somewhere I have a great humorous photo I shot of Warren in an "administratively closed" cave in the Mojave desert, and then we promptly got arrested for trespassing.

    But I talked us out of it.

    Gotta watch out for those science teachers.

    --
    If it don't GO... chrome it. ~ Frank Banks
  18. oscillating reactions are reasonably well known by StandardDeviant · · Score: 3, Interesting

    I did a math paper for a mathematical modeling class during my chemistry undergrad on the BZ reaction mechanism, which is another oscillator like the system in TFA. It's not a perpetual oscillation, but with precisely controlled reagents you can get some pretty long-lasting oscillations (precisely as in on the order of hundredths of a mole, iirc). There's a really good little book in the oxford chemistry primers series (series as a whole is quite nice for accessible, focused introductions to various fields) on this topic: Oscillations, Waves, and Chaos in Chemical Kinetics by Scott.

    --

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  19. It's still not fully explained. by Anonymous Coward · · Score: 0

    I'm sure though that there will be a half dozen explanations in this thread, inbetween the 'OMG PERPETUAL M0TION!!' and 'This is sooo a dupe' comments. Here's a starter: The beaker was possessed by a bound daemon manifested from the black atheistic heart of the cold, calculating scientist, cruelly confounding him with the inexplicable as to send his very soul into the eternal torment of the Abyss.