Advances in Supercooling Science

Researchers have discovered new properties of supercooled water. It has long been known that clean water with no particulates that is placed in a smooth enough container can be cooled below its freezing point of 0 C (32 F) without freezing.

They found certain forms of particles hitting the water can microscopically (subatomically) cause it to freeze if it’s supercooled first. Some particles (neutrons) but not others (gamma rays) trigger freezing.

This could lead to better detectors for nuclear weapons in cargo for homeland security, understanding cloud formation, and providing clues as to how certain mammalian species hibernate, supercooling their blood somehow.

11 thoughts on “Advances in Supercooling Science”

  1. Seems strange here the claim that neutrons can trigger freezing… The application mentioned as using this seems even more nebulous. There is something like 50 n/sq-cm/hr neutron background… like 2 neutrons pass through your cell phone every second.

  2. Right, here the biological compounds render supercooling stable against small perturbations by masking nucleation centers. And there’s a little bit of osmotic antifreeze going on, as is always the case for animals, because their blood isn’t pure water.

    I wonder if the fish can actually recycle the masked nucleation centers and masking compound, or just count on not running out of capacity before the temperature goes up again in the spring?

  3. Based on the abstract alone, I think this is a case where these two phenomena are combined. Or more precicely, it’s combined with anti-freeze, which is a 3rd phenomena, where an additive alters the freezing point.

    In this case, the anti-freeze enables supercooling (as I understand, beyond the altered freezing point, otherwise it wouldn’t be supercooling) by changing the dynamics of freezing. So instead of only needing a minor disturbance or nucleation site in the usual case, here you need a much bigger disturbance for ice to form, so there’s more room for supercooling.

    At least that’s my interpretation. The phenomena are related, but separate. You can have supercooling without anti-freeze or vitrification, and I expect that you can have vitrification or anti-freeze without supercooling. Or you can have them combined, as in this example.

    One final word of caution: sometimes terms are used differently in different areas of science. This doesn’t seem to be the case here, but it might be.

  4. No, actually supercooling IS seen in some arctic fish.

    You can tell that it’s actual supercooling, because when you do manage to initiate freezing by overwhelming the anti-freeze, you get a temperature over-shoot, which is NOT seen with anti-freeze that works on the normal, osmotic principle.

    Also, once freezing has occurred, thawing takes place at a substantially higher temperature. That’s an absolute signal of supercooling, a freezing point that’s lower than the melting point.

    These fish are in a very precarious condition, and can almost instantly freeze if their protection system is overcome.

  5. The usual advice, if you’re going to microwave empty water, leave a wooden stick in it (like a popsicle stick or a toothpick). It provides the nucleation sites for steam to form, so you won’t get superheated water.

  6. I think you and Brian are confusing supercooling with vitrification. Those are different phenomena.

    In supercooling, ice fails to form below freezing temperature because of a lack of nucleation sites. But as soon as a nucleation site is introduced or the liquid is disturbed, ice forms very rapidly. The same happens with superheating, except there the nucleating species is vapor. In this article, neutrons provide the necessary disturbance probably by collisions with atoms in the water.

    On the other hand, in vitrification, ice crystals form, but can’t grow because some chemical gets in the way. In more extreme cases, it gets so much in the way, that crystals can’t form at all, and you get a glassy (disordered) solid.

    I don’t think that supercooling is possible in blood. First, there are way too many nucleation sites in the form of cells and proteins. Second, in a live person, the blood flows, and the flow is turbulent.

  7. I’ve always regarded excessive cleaning in the kitchen as dangerous. Household cleaning in general actually.

  8. I was under the impression that the supercooled blood thing was already understood: Chemicals in the blood that are attracted to ice nuclii, and coat them, stopping them from growing.

    I’ve occasionally accidentally superheated water in the kitchen, (Easy to do with a microwave, if you’re good about cleaning your containers, and have reasonably clean water. Dangerous, too!) I think I’ve only once accidentally supercooled it, though.

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