Saturday Morning Science Experiment: Ice cold outside, "hot ice" inside

Sodium acetate is such a useful little chemical. Not only is it responsible for the awesome flavor of salt and vinegar potato chips, but it also produces the heat in those little reusable hand and foot warmers you can buy at outdoor stores. Plus—when it's just too damn cold outside and you'd rather spend the day indoors—the same reaction that keeps your fingers and toes toasty can also be used for fun at-home art projects.

You can buy sodium acetate online, but all the real Cool Kids are making it themselves.

Thumbnail image courtesy Flickr user puroticorico, via CC

Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.

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Anonymous

Strangely enough a similar thing also happened to me in my freshmen dorm, though on a regular basis. We would refill our water bottles and place them on the top shelf of the mini fridge. The freezer section was right above it, and made those bottles extra cold. When you would pull one out, you could flick or tap the side and it would quickly freeze just like in the video. Me and my roommate would even use it as a joke of sorts when someone ask for water. Our whole fridge was too cold oftentimes, even causing whole milk to have little ice bits in it.
Cactaur

Would it simplify the process to just make a supersaturated solution of MSG?
Anonymous

Re: Processing what that darned freeze frame was depicting
Levels of realization
1) It’s an ass!
2) It’s legs!
3) Fingers.
Anonymous

What would happen if when he touched it, he left his finger in?
- Anonymous
  
  If he left his finger in, all the water in his body would crystalize, and he would die.
EvilSpirit

Anonymous #25:

Since the reaction is exothermic, you could use if for *warming* booze. Also for making it taste like salt and vinegar.
- Anonymous
  
  D’Oh!
  
  Thanks for the answer, is pretty obvious that it will release heat…
  
  Sorry for doing such a stupid question.
  
  PD: Maybe I can use it to keep hot a cup of chocolate :P
Fang Xianfu

I was disappointed that the second sculpture didn’t turn out to be a cock-and-balls, but I guess you can’t have everything.
Anonymous

Is this thing toxic? I mean, can I use it for cooling booze?
frankieboy

So this is the stuff in salt and vinegar potato chips? A few weeks ago I ate the chip bitties left in the bag of Cape Cod S&V chips, and my tongue felt like it had been chemically peeled for two or three days. Disgusting! I’m cured of those things.
- EvilSpirit
  
  What your tongue had been, basically, was *pickled*.
- Jonathan Badger
  
  Considering that salt is sodium chloride, and vinegar is acetic acid, it is pretty obvious that the flavor of salt and vinegar potato chips is from sodium acetate. But that sounds so much scarier than “salt and vinegar”, doesn’t it? It’s like Japanese seaweed extract. If I tell you that that Japanese have used this natural substance to flavor their food for centuries, it sounds charming, doesn’t it? If I tell you that this extract is technically monosodium glutamate (MSG), it sounds all chemical and scary.
Anonymous

I came back to my dorm from spring break or something and when I took my full brita pitcher out of the fridge it did the exact same thing as the first experiment. I stood there complete dumbfounded as the entire thing slowly froze solid. I was the first person back from break so nobody was there to show. I wonder now if someone slipped some sodium acetate in it or if there was some weird cross contamination with chips or Boston’s water.
- fencepost
  
  What you probably had there was supercooled water – it was below freezing, but had never started to crystallize around an impurity. When you disturbed it, the crystallization process started immediately.
  
  I have some little freezable pouches of something (probably just water) that don’t solidify immediately, but when I take them out of the freezer and flick them with my finger they opaque up and solidify.
- Anonymous
  
  A brita picture in the fridge alone would not become supercooled enough to instantly freeze. Freezer, sure, fridge no.
  Not unless everything in your house was super cooled too.
  
  Additionally, the charcoal in the filter would provide ample nucleation for any water to freeze FAR before becoming super-cooled.
  
  So either you’re full of $hit, or it wasn’t a FULL brita picture in the fridge.
Keneke

I haven’t been this freaked out since watching those undulating cornstarch tentacles caused by an audio vibration.
Anonymous

First thing I thought of was Ice Nine too!
- Anonymous
  
  Water would only flash freeze if super cooled beyond the freezing point of water, and the container must be extremely clean (no dust or anything to provide a seed for any crystals to form).
  If your water was room temp then this didn’t happen.
Anonymous

the video still before it’s played looks like a naked dude from behind stepping out of a tub of water too small for him.
davedorr9

Yay for Maggie! I loved this one.
Anonymous

It’s ICE NINE!!!
Antinous / Moderator

It’s Saturday morning? This is the worst hangover ever.
Hawley

science = bad
tradition = good
Jellybit

Why does this react to a finger touching it, and not a plastic container? And why did it turn to ice when it touched the other dish? What exactly causes it to turn to ice suddenly?
- Hawley
  
  nucleation
- Anonymous
  
  I think JellyBit was wanting to know what sets off the reaction when the finger touches it, is it the oil in skin, the rough texture of skin, the temperature.
  
  what starts the chain reaction?
  
  I am curious also.
  - Camp Freddie
    
    For the curious – it’s the rough texture of the finger that is the key to the crystallisation.
    
    Also, I definitely agree that the sculpture was a cock-and-balls-fail
  - Anonymous
    
    It was the rough texture of his skin. It provides a seeding surface for the super-concentrated chemical to crystallize.
    Sudden agitation can also cause the crystallization to start (which is what happens in the commercial hand warmers when you flex the disc inside).
- Anonymous
  
  the rapid solidification process occurs through what’s called homogeneous nucleation. the solution has been supercooled. it was poured very gently into a smooth walled container. this allowed the solution to remain supercooled. upon touching the solution the rough ridges in your fingers, the slight increased temperature and the impact of touching it create nucleation sites. This solidifies the solution near your finger and then creates more nucleation sites and the solid grows out like a dendrite.
  - Anonymous
    
    Actually in this case it wasn’t supercooled.
    Sodium acetate (like many other crystal forming compounds) will crystallize at room temperature if super-concentrated.
Anonymous

What is inside the sodium acetate that makes it freeze with water???????????
http://~ Anonymous

Wow, We did something like this in Chem20 last year.

By boiling the solution (NaCh3COO + H20) the amount of solid that can be disolved by the water increases.

When cooled there is actually more SodiumAcetate in the solution then there should be (super saturated solution).

When any kind of major force is applied the crystals rearrange themselves and being unable to go back into their liquid form they collect on one another and make crystals!

(Or something along those line, More of a physics/Comp Sci guy)

When I heated mine in a test tube I forgot to take the stopper off the top and the whole thing blew. Covered my backside, hair & thhe table in liquid. Cool thing is that it started to crystalize in my hair after. Look cool :P