WTF? Did that shit just freeze?!
Katzenklavier
Regular
Yes, it did. What froze was sodium acetate. It's an organic chem used in salt&vinegar potato chips as a flavoring. One remarkable ability of sodium acetate is it's affinity for forming supercooled solutions.
A supercooled liquid is one that has chilled below it's melting point without freezing. This happens when there are no nucleations, or starting spots for crystals to form. Any liquid can supercool, even water. Water has to be very clean for supercooling though. Try leaving a fiji water bottle outside during winter and it will likely supercool.
Sodium acetate solutions don't need to be ultra pure to supercool though. Why? Well when the solution cools it also becomes supersaturated. This means there is more dissolved then there is supposed to be at that temperature. Sodium acetate's affinity for supersaturation leads to it's ability to easily supercool, even when there is some dirt in the solution.
Sodium acetate is very cheap, and it can be bought for about 5 bux a pound online. One pound makes about a liter of solution. All you need to do is add it to a few cups of hot water (~150*F) until no more will dissolve. Then let it cool. If crystals start to form then you need some more water, add some hot water +stir and the crystals will redissolve.
Now put the solution in a dish or a jar and cool it. The colder it gets the faster it will freeze.
After the liquid is cooled, disturb it. Dip your finger in it or drop in a few grains of acetate. This forms a nucleation point and it will freeze! It will also heat up quite noticeably. Remelt and use again.
When warm:
When cold:
A supercooled liquid is one that has chilled below it's melting point without freezing. This happens when there are no nucleations, or starting spots for crystals to form. Any liquid can supercool, even water. Water has to be very clean for supercooling though. Try leaving a fiji water bottle outside during winter and it will likely supercool.
Sodium acetate solutions don't need to be ultra pure to supercool though. Why? Well when the solution cools it also becomes supersaturated. This means there is more dissolved then there is supposed to be at that temperature. Sodium acetate's affinity for supersaturation leads to it's ability to easily supercool, even when there is some dirt in the solution.
Sodium acetate is very cheap, and it can be bought for about 5 bux a pound online. One pound makes about a liter of solution. All you need to do is add it to a few cups of hot water (~150*F) until no more will dissolve. Then let it cool. If crystals start to form then you need some more water, add some hot water +stir and the crystals will redissolve.
Now put the solution in a dish or a jar and cool it. The colder it gets the faster it will freeze.
After the liquid is cooled, disturb it. Dip your finger in it or drop in a few grains of acetate. This forms a nucleation point and it will freeze! It will also heat up quite noticeably. Remelt and use again.
When warm:
When cold:
Comments
I bet it would fucking suck to stick your hand in there and let it freeze, lol.
http://en.wikipedia.org/wiki/Supercooling
I was going to post something about this but it looks like katz beat me to it.