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Original air date:
11.21.07
A Chemistry Teacher Illustrates the Beauty of Supersaturation
It's not every day that you can watch a piece of crystalline white "ivy" growing centimeters-per-second in front of your eyes. But then again, it's not every day that you get to hang out in the lab with chemistry guru Chris Schrempp.
Dr. Schrempp, a chemistry teacher at Los Osos High School in Rancho Cucamonga, California, doesn't need much for this particular experiment: just safety gloves and goggles, a beaker, hotplate, watch glass, water and sodium acetate, the chemical that gives salt & vinegar potato chips their flavor. These few ingredients are enough to make what is called a supersaturated solution, a mixture that contains more solute than it would under normal circumstances. As Dr. Schrempp illustrates, supersaturated solutions are really itching to get rid of their extra solute and will do just about anything to "free" themselves of it.
After mixing a solution of water and sodium acetate trihydrate, Dr. Schrempp waits until the solution cools down, at which point it becomes supersaturated. Then he pours it slowly onto a watch crystal on which a few small crystals of solid sodium acetate already lie. What happens next is rather exquisite, enough to make every nerd molecule in host Chris Hardwick's body vibrate: The exothermic, or heat-releasing, reaction builds a large sodium acetate crystal while warming the surrounding air. In this beautiful way, the solution rids itself of its excess salt and returns to equilibrium.
Watch Dr. Schrempp do his supersaturation magic in the WIRED SCIENCE studio and see for yourself just how cool simple chemistry can be.
13 Posts
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11.21.07 6:07 PM PST
yeven
wow i love it!!! but could you tell me is this the same reaction that causes face cleaners that heat on contact with water????and if not how does that work? applied science is always more fun:)
11.21.07 6:44 PM PST
Mac Renfro
I once had a student that had a plastic pouch that produced heat when a small metal disk inside the bag was deformed. Then it could be restored in a microwave for the next time it was needed.
Can I build these or are they still available somewhere?
MRenfro@att.net
11.21.07 6:49 PM PST
Val Thomas
Cool demo, great for an IPC class. Will definately share with my students. I look forward to many more interesting demos.
11.21.07 7:43 PM PST
brooke
can you send me the RECIPE!!!!!!!!
11.21.07 7:51 PM PST
BROOKE
will it ever melt i hope it doesnt.
11.21.07 8:48 PM PST
pamela700
where'd you get that amazing "Chemistry Power" t-shirt with the running flask? i've looked all over for it...it'd make my biochemist pal a great Christmas gift!
12.28.07 6:10 PM PST
Joe Noyes
I was so proud to see that my nephew was on public television. How about getting busy and coming up with an alternative to the use of gasoline. Any chance of getting your autograph?
1.20.08 7:36 PM PST
Linxi
YAY DR. SCHREMPP on TV
I'm the proudest student ever
2.5.08 8:19 AM PST
Trip
How much water and sodium acetate are used in this experiment?
2.10.08 11:28 PM PST
Steve S. R.Ph.
DR Schrempp Pharm D? a possible display for your show.
One of the coolest Organic chem labs we ever did in Pharmacy school Oregon State U was the formation of nylon. Essentially 2 liquids with the nylon pulled from the interface, rolled on a stick. This combines physics principles of conservation of energy ( both liquids end up as a solid) and an explanation of why nylon is so strong relative to it's weight. You can correlate sisal or manila ropes( made by multiple short fibers laying together requiring a large diameter for strength) versus nylon's multiple strands of fibers running the entire length of the rope. With Nylon's added resistance to rot.
Great shows
7.10.09 9:03 AM PDT
graycat46
It's been so many years since I took a basic class in Chemistry. It's exciting to see new ways to educate and
inspire the awah with which we all must hold the way "it"
all works so well when we can "unlock" the "secrets" and
share with the next generation who will take it to new
heights ie. Bill Gates etc.
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