Fun chemical reaction video

The Wired Science blog posted a YouTube video of a liquid that changes color from clear to yellow to blue over and over again.

In 1973, the spectacular demonstration was perfected by Thomas Briggs and Warren Rauscher, two amazing high school science teachers.

Over thirty-five years later, chemists are still trying to fully understand how it works.

What they do know: Several reactions take place at once. One of them produces iodine, which gives the amber color. Hydrogen peroxide reduces other chemicals into iodide ions. Along with normal iodine, the charged particles interact with starch to create it a blue-black color. The speeds of those transformations are constantly changing. As one overtakes the other, the color suddenly changes.

Link

[#1 posted by ill lich , January 10, 2008 10:36 AM]

This could single-handedly resurrect the lava lamp industry.

[#2 posted by Jeff , January 10, 2008 10:53 AM]

I'd like to see this change in slow motion with hi-def.

[#3 posted by meowdip , January 10, 2008 10:56 AM]

The most famous oscillating reaction is the Belousov-Zhabotinsky reaction, which also produces some nice colors. When the reaction isn't stirred you get interesting waves of color moving through the solution. Search youtube, there are a bunch of videos of varying quality.

[#4 posted by Evil Jim , January 10, 2008 12:41 PM]

Interesting reaction, but what does it mean!??

[#5 posted by Duo , January 10, 2008 1:29 PM]

Would this count as perpetual motion?

[#6 posted by NovySan , January 10, 2008 2:02 PM]

Ha ha! My undergrad chem professor did this one at U of I, where our colors are orange and blue, while singing the school fight song.

[#7 posted by univac , January 10, 2008 2:49 PM]

Wow! How long will this continue reacting?

[#8 posted by SC_Wolf , January 10, 2008 6:05 PM]

It's like they took Nightcrawler's BAMF! visual effect from the X-Men movies, and bottled it.

[#9 posted by Cheqyr , January 10, 2008 7:32 PM]

@5 Not in the "get more energy out than you put in, forever" sense, because that's impossible. I suspect that one of two things is going to happen:

1) Eventually the system will reach a state of equilibrium and no further reaction will happen; or,

2) The color changing will continue indefinitely, but only because it's powered by the ambient heat/light of its surroundings.

My money is on #1.

[#10 posted by ill lich , January 10, 2008 8:48 PM]

It can't count as perpetual motion if it's not a closed system, and they seem to be adding energy via the vibrating plate the beaker sits on (in fact it looks like he turns up the speed after pouring in the 2nd solution, or at very least the plate is still on as the power light is on.)

[#11 posted by Crash , January 10, 2008 9:11 PM]

You can learn a lot more about the Briggs-Rauscher reaction at Wikipedia and elsewhere. It doesn't run endlessly nor pick up energy from the mixer, but slowly peters out after about a dozen oscillations as its reagents are consumed.

You can try it at home if laboratory glass is legal in your state. It requires household peroxide, distilled (not filtered) water, potassium iodate, sulfuric acid, malonic acid, MnSO4, and starch.

[#12 posted by Takuan , January 10, 2008 9:44 PM]

United Nuclear video

http://www.pbs.org/kcet/wiredscience/video/82-dangerous_science_video_.html

[#13 posted by DougO , January 10, 2008 9:48 PM]

This is one of the classic demonstrations of a dissipative structure known as a "chemical clock" that demonstrates ordered behavior stemming from "far from equilbrium thermodynamics." See here:
http://www.faidherbe.org/site/cours/dupuis/oscil.htm
http://staff.science.nus.edu.sg/~parwani/c1/node60.html