Sciencey Question

[Ellie]

Ok so my brain was killing me the other day.

Solids, liquids, gasses, they all happen at different points, I know that much. For ex. iron turns into a liquid a lot higher than mercury does!

But given there is the concept of an absolute zero, even if it is an unacheivable concept... at absolute zero, is everything solid? I.e. is that the starting point of any element's scale?

I know that heat is just entropy and absolute zero is the point of least entropy but does that mean if you take anything and cool it down to absolute zero (or, let's say 0.00001 degree above absolute zero), it will become solid?

Just something I've always assumed - hopefully someone knows if that's a wrong assumption.

 

[Glitchfinder]

I'm not sure on the answer to your question, but I would like to point out that absolute zero itself is achievable. However, by attempting to measure the temperature of something at absolute zero, you have to interact with it in a way that introduces energy, meaning that it is technically impossible to measure absolute zero as a temperature.

That being said, absolute zero is the minimum temperature because it is the point at which atoms lose all of their thermal energy, and literally stop moving. The higher the temperature, the more they're moving and trying to break free, but at absolute zero, they just sit there, doing nothing. I'm not sure on the official definition of the physical states, but I'm pretty sure it has something to do with the movement of atoms and molecules, so it might actually be true to say that everything is solid at absolute zero.

 

[dadevvtsvre]

I'm not sure about the other noble gases but at absolute zero, helium remains a liquid. (at standard pressure) The zero-point energy of helium is too high for it to freeze, even at absolute zero. (zero-point energy being the lowest amount of energy possible for a substance to have. meaning, even at absolute zero, helium still has enough energy for it to remain a liquid.) Things get complicated when you introduce differnt pressures, supersolids and superfluids, etc. but the simple answer is that no, not every substance will be a solid at absolute zero, because helium isn't.

Unless you mean to include different pressures as well, because I *think* that you can get solid helium at absolute zero if you raise the pressure, but am not 100% sure of this part.

 

[Ellie]

So with pressure, it is possible to get below absolute zero? Or, at least, representitive of.

 

[dadevvtsvre]

By 'get below', do you mean the amout of energy in an object? The amount of energy in helium at absolute zero will not change with pressure, pressure only affects how the atoms interact with each other. Again, this is way out of my league and I could be incredibly wrong, but from what I've gathered pressure reduces the space between helium atoms so that, at a very specific pressure, the atoms will stop bouncing around long enough for a solid state to be achieved, however temporary.

It's not an easy thing to do.

Actually your question raises another interesting point - if you took a normal room filled with normal air and cooled it down to absolute zero, would all the nitrogen and oxygen and argon and everything else in the air solidify as well? Would you get a bunch of solid nitrogen and oxygen raining down on the floor, leaving empty space? All theoretical obviously but it's kind of neat to think of.

 

[psiclone]

Then, if they all solidified and fell, wouldn't that cause the temperature to rise from the molecules bumping into each other, creating heat, and ultimately undo the solid state?

I'm just talking out of my ass.. I know nothing of this other than what's already been said in this thread, which prompted my question.

 

[Perihelion]

Helium is the only element that does not become a solid at absolute zero and 1 atm. It does, however, solidify under additional pressure. The reason for this is not because the energy somehow lessens but because as you force atoms closer together, the only place for the atoms to go is into the solid state formation. A solid is a compact arrangement of molecules, not necessarily a low-energy one. Low temperature is what usually lets the molecules get close enough to each other to form a solid because they're not bouncing around as much, but molecules will do basically the same thing regardless of whether they're close together because their low energy permits them to be close together or because they're forced to be close together.

At least, that's my understanding. I skipped half of solid state chemistry, so I'm not sure I'm articulating all of the details correctly, but that's more or less right.

 

[Juan J. Sánchez]

Actually, at near zero temperatures, certain elements form new states of matter. Google Bose-Einstein condensate.

 

[Glitchfinder]

Actually, at near zero temperatures, certain elements form new states of matter. Google Bose-Einstein condensate.

That has never actually been replicated, the last time I checked.

 

[Norton]

http://www.ptable.com/

This should answer your question easily enough.

 

[Danielle]

The very notion of "solid" confuses me. I mean, does something just become solid, after having been a liquid? Or is there a transition between? I can't imagine the atoms would just go from being active to being not, at a certain temperature.

 

[Ellie]

Solid defines something that doesn't take the shape of it's container or expand to fill it, loosely put. I'm not sure when one suddenly becomes another but there definately are clear differences between each state of matter.