It might help if their science teachers weren't dunces.
Five stars for sweet, sweet stupidity.

It was even tricker than they had us believe!


"The melting point of ice at 1 atmosphere of pressure is very close [2] to 0 °C (32 °F, 273.15 K), this is also known as the ice point. In the presence of nucleating substances the freezing point of water is the same as the melting point, but in the absence of nucleators water can supercool to −42 °C (−43.6 °F, 231 K) before freezing."

42 likes, man.

Yes, there's been a daytime version forever. Meredith Vieira used to host it. I think i like her more than Tom Bergeron.

Does Tom Bergeron host everything now?

I'm not a huge believer in 'common sense', but it is common knowledge that ice melts at 0C and water freezes at 0c. Or 32F, whichever you prefer.
This is a 0 question, they weren't expecting miracles out of the guy.

I guess though, maybe he grew up somewhere where it rarely hits the freezing point, and has never felt the massive appreciation for a 0C day after months of -30C. Or the hatred of a 0C day after months of +30C.
You do notice this little fact about water when you put up with that annually.

Yes, but looking at the youtube comments, some people are trying to suggest things like "well you can never really get it to *exactly* 0C" to resolve the apparent paradox. I wouldn't doubt if his brain was trying to scurry down a similar path.

The thing here is that he's a science teacher. The concept of water freezing should be as rudimentary to him as 2+2.

Pure water can be supercooled below 0C and remain liquid. Initiate the crystallization with a shock, and won't the resulting mass of frozen water subsequently melt at 0C?

You could defend any of them if you got nitpicky enough. http://en.wikipedia.org/wiki/Ice#Phases

That's the kinda overthinking that fucks you up if you're used to asking/answering stupid theoretical questions like "would a planet made entirely of water be ice in the middle, from pressure?", "at what temperature does water boil and freeze in outer space?", "How much water would you need to create a black hole from its gravity?" etc.

He should have said "At how many atmospheres of pressure?"

@OscarWildcat,
Not sure if you are asking, but yes, it will once you put enough energy in it (its temperature will be 0C just before it melts).

Melting points don't really change the way freezing points do.

So just to be clear: I can do an experiment in my kitchen fridge with a bottle of distilled water that disproves the claim that water's melting and freezing points are the same. But that's the wrong answer, and I failed the test.

OK, that's about par for the course here.

Actually as you pump energy into a glass of ice water its temperature does not increase. The water will remain at 0° until all the ice is melted and then the water temperature will increase. I remember doing that experiment in Chem 101.

Though we were just letting the ice melt naturally from room temperature, if you applied enough energy the water furthest from the ice would increase.

But most importantly HE'S A FUCKING SCIENCE TEACHER.

@Oscar Wildcat,
Your understanding is certainly correct in that sense. Under standard conditions you can supercool water down to temperatures lower than the melting point (which is, under standard conditions, doesn't really change). This is how we make slushies.

Freezing is a multistep process (whereas melting isn't really). You have to form a nucleus first...so as long as you lower the bulk temperature to an end point before a nucleus forms (the rate of which is also temperature/pressure dependent) you can have meta stable liquid water.

But then how can we say that the fp of water is 0C? Well, a volume of water will *tend* (or "eventually") freeze if left at 0C if you leave it long enough (you can promote nucleation with a rough surface to make sure you are not stuck in a kinetic trap). it will never freeze if you leave the water at +0.1C.

We define things like freezing point in terms of thermodynamic equilibrium (at the end of time) vs. a metastable state.

That first paragraph is all muddled...:

Your understanding is certainly correct in that sense. Under standard conditions you can supercool water down to temperatures lower than the freezing point. This is how we make slushies.

If the treadmill is going fast enough, it still has a 1 in 3 chance of winning.

Xenocide? I love you. Here. These are five fiery ice cubes just for you.

I spit my lunch

Magnets? How do they work?

He shoulda done like Feynman did to that BBC reporter who asked him how fridge magnets work and gotten real pissed off, all "You tryin' to make a jerk outta me? That'd take hours to answer!"