Monday, March 25, 2013

Supercooling water

Earlier this week while I was gone on vacation in the Keys of Florida, I saw a video online that just baffled me. It had to do with supercooling water, something I've never even heard of before. The video was shown to me by a friend.
 A man claims he had a water bottle in his car unopened which he would have expected the water to freeze in the bottle, but it hadn't. He then says that he threw the bottle in the passenger seat, and it instantly started to freeze from top to bottom. You'll see in the video that he demonstrates this again, by leaving a water bottle outside all night, the water doesn't freeze, he then takes the bottle upside down and taps the top. From there you can visibly see ice form from top to bottom of the whole bottle, within seconds.

I then started doing a little research on what exactly would cause this to happen. After reading a few different articles online I figured out that this is something called "Supercooling". According to Science Daily this article states that "Supercooling, a state where liquids do not solidify even below their normal freezing point...". This supercooled liquid is stuck in a metastable state, even though its below its freezing point. Metastable state is an excited state of an atom, nucleus or other system that has a longer life time than the ordinary excited state. This metastable state can only be achieved in the liquids that do not contain seeds that are needed to start crystallization. These seeds needed to crystalize need some sort of nucleus to hang on to, that way the crystals can form. Which would cause the liquid to start to freeze instantly. According to an article on Squidoo.com liquids will not form to a solid if there are no seed crystals or nucleus around the liquid. Although, there is a maximum freezing point that will allow the liquid to freeze with or without seed crystals, and nucleus. This maximum temperature is -42 degrees Celsius. If I remember correctly as stated in the video the temperature outside was -20 degrees Celsius, which wouldn't be quite the maximum freezing point.

Some believe that because there may be some impurities in the water bottle, due to it being filtered water that helps with the supercooling. When the impurities are shaken (when the water bottle is flipped upside down) seed crystals are able to attach to those air bubbles, and/or small impurities. Once on seed crystal can attach to something it will start to crystalline, which then becomes a chain reaction. A crystalline structure is then formed, causing the liquid in the water bottle to freeze within seconds right in front of you. 

This video was incredibly unique and mind boggling. I highly recommend any of you science oriented people to take a look at this video. If you haven't heard of supercooling before it really makes you think, what could possibly cause something like this to happen? Why would the liquid freeze when being left outside at its freezing temperature? When researching more about this "supercooling" method, I found out that it's a very easy experiment to test on your own at home. I have yet to try it, but I absolutely plan to as it actually hurt my brain to think for so long about how this could happen. I hope that you all find the video as interesting as me, and possibly try the experiment on your own as well!

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