Could water supercool if it was in a strong enough container?

Is there a material strong enough that if you put water in a container made of it, the water wouldn’t be able to freeze?

It would be trivial to make a container which wouldn’t allow the water to expand.
It would still freeze though. There are many forms of ice.

You’ll need a lot of pressure

You may have heard about superheating water in a microwave. Basically, if the water is pure enough and the container is smooth enough, there won’t be any easy nucleation sites for the steam bubbles to form around, and the water can be heated to a temperature well above its boiling point. It’s not terribly stable, and any disturbance (like picking the coffee cup up) tends to result in the entire thing flashing to steam rather explosively, which can be rather unpleasant considering that the cup at that point is in relatively close proximity to your face.

The same sort of thing happens on the freezing end. You don’t need a strong container, you need a very smooth container. And your water needs to be fairly pure. The lack of nucleation sites will prevent ice from forming. Once it is well below freezing, giving the container a good whack will make it freeze.

Here’s a fun video about it:


Theoretically, if you have very, very pure water and a very, very smooth container, and you cool the water slowly, it will never crystallize and instead will eventually become a glass instead of a crystalline solid.

Not exactly. Only Ice Ih is less dense than water. There are many other solid forms of water, all of which are more dense than liquid water. Unfortunately the phase diagram of water is complicated, so it’s not an easy question to say exactly what happens without calculation. I think as you cool below 0C you’ll initially get some mixture of liquid water and Ice III (density 1.1 g/cm^3) or Ice V (density 1.2 g/cm^3), and quite possibly even some plain old Ice Ih (density 0.9 g/cm^3), depending on the temperature at which you started the experiment (which determines the starting molar volume of your water). As you cool further you’ll get more of III or V and less water, and Ice II (density 1.2 g/cm^3) may make an appearance. I think ultimately you end up with a mixture of Ice II and Ice Ih that has the same density as your starting sample.

As long as you don’t EVER achieve Ice IX, you should be fine. As should the rest of the planet.

Just to be clear, that’s a joke. Fictional ice IX (https://en.wikipedia.org/wiki/Ice-nine) is very different from real world ice IX (https://en.wikipedia.org/wiki/Ice#Phases)

Actually it doesn’t need to be pure at all. Here’s a video of the same thing with beer.


and a better one with coke
I think the important part is the water can't have "chunks" in it.