Weird Water!?

Question

So.. I left a bottle of water in the freezer for maybe 4-8 hours.... (I don't really know exactly somewhere around there...) It was on it's side and clear. Not frozen or filled with ice at all... And the i picked it up and suddenly it just froze and got icy and ice appeared! Any explanation?

Answer 1

Wow, I wish I had luck like that!

Sounds like you had a super-cooled solution there - the temperature was below its freezing point, but it hadn't actually started to freeze. Why not? Because to do that it requires a nucleation site - somewhere for ice crystals to start to grow. This is usually provided by a speck of dust or an imperfection on the surface of the container (like a scratch on a glass bottle, for example). Once a nucleation site is found, ice crystals start to grow at it, and more ice grows on top of that ice and pretty soon, the whole thing is frozen.

Now, the most spectacular thing about a supercooled solution is what you saw - once it starts to freeze, it all freezes very suddenly. What happened when you agitated the bottle was that you gave the water a little push to get it to start freezing - maybe by deforming the side of the bottle a little when you picked it up, or perhaps just by pushing a little pressure wave through the solution. Whatever it was, that little push meant that a little bit of ice formed in the bottle, and suddnely all the other water molecules realised that they really didn't want to be water at -5oC --> and one almighty rush to form ice crystals began.

Usually to form supercooled solutions, you have to be very careflu to exclude any nucleation sites like dust, so you've been lucky to see this without really trying!

Answer 2

It is a question of nucleation ,in the fridge your water supercooled(remained liquid below it's true freezing point)this is because for a new phase to form(liquid to solid,or liquid to gas or even one solid phase to another,It is first necessary for the first particle(nucleus) of the new phase to become big enough to grow;when it is at this critical size it will grow.Normally when a liquid is cooled slowly below its freezing point many nuclei appear but many disappear because at these very small sizes surface tension is enormous and "squeezes them out of existence".Eventualy some will be lucky and a few more molecules will join the embryo before is squeezed and such nuclei will become critical and grow.When you shook the bottle microbubbles formed and these,together with their contact points with the sides of the bottle made easy sites for nuclei to grow.
This nucleation thing is very interesting: you will notice that ice formed on windows or car windscreens makes big frondy patterns when cooling is slow(or not much below freezing point)but only small crystals of ice if cooling is fast and severe.In the first case all the water has freezes from only a few nuclei and the crystals can grow large,inthe second case so many nuclei grow that the crystals have no chance to grow very big.

Answer 3

Water (H2O, HOH) is the most abundant molecule on Earth's surface, composing 70-75% of the Earth's surface as liquid and solid state in addition to being found in the atmosphere as a vapor. It is in dynamic equilibrium between the liquid and vapor states at standard temperature and pressure. At room temperature, it is a nearly colorless, tasteless, and odorless liquid. Many substances dissolve in water and it is commonly referred to as the universal solvent. Because of this, water in nature and in use is rarely clean, and may have some properties different than those in the laboratory. However, there are many compounds that are essentially, if not completely, insoluble in water. Water is the only common, pure substance found naturally in all three states of matter—for other substances, see Chemical properties.

Answer 4

Super-cooling is what it's called.
You can look up the phrase.