Chemical Reaction Changes Color Over and Over

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."

Comments

Huh?

[moosesocks]

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!

Re:Huh?

[paintballer1087]

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.

Re:Huh?

[The One and Only]

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.

Iodine Clock Reaction

[Anonymous Coward]

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

oscillating reactions are reasonably well known

[StandardDeviant]

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.