Come on, yet another type of matter?

[steevey]

You get what happens in the video.

 

Well he transfers kinetic energy to the helium and it moves, but if the atoms go to a higher energy state, wouldn't it not continue to be a super fluid?

[swansont]

Well he transfers kinetic energy to the helium and it moves, but if the atoms go to a higher energy state, wouldn't it not continue to be a super fluid?

 

That's what he says in the video

[steevey]

That's what he says in the video

 

But can't I just put the atoms in a higher energy state just by moving them or accelerating the substance?

Edited April 28, 2011 by steevey

[swansont]

But can't I just put the atoms in a higher energy state just by moving them or accelerating the substance?

 

That's what you are doing when you increase temperature — you give them more KE. They are in a higher energy state and because of that they are no longer in the superfluid (ground) state.

[steevey]

That's what you are doing when you increase temperature — you give them more KE. They are in a higher energy state and because of that they are no longer in the superfluid (ground) state.

 

So then how could be actually be frictionless if any movement puts the atoms in a higher state than the ground state, thus not making it a super-fluid?

Edited April 29, 2011 by steevey

[swansont]

So then how could be actually be frictionless if any movement puts the atoms in a higher state than the ground state, thus not making it a super-fluid?

 

The ground state is not a zero-motion state.

[steevey]

The ground state is not a zero-motion state.

 

But if I'm just moving it around in a vile, thats adding KE, and that increases the energy level, so how does this whole thing work out? Would you have to keep colling it as your moving it?

[swansont]

But if I'm just moving it around in a vile, thats adding KE, and that increases the energy level, so how does this whole thing work out? Would you have to keep colling it as your moving it?

 

The center of mass motion of the bulk doesn't matter — that's not how temperature works. Throwing an object in and of itself, doesn't make it hotter. There's a also a matter of scale: a helium atom at 2K has an average speed of almost 100 m/s

[steevey]

The center of mass motion of the bulk doesn't matter — that's not how temperature works. Throwing an object in and of itself, doesn't make it hotter. There's a also a matter of scale: a helium atom at 2K has an average speed of almost 100 m/s

 

I think I can get how it can still move, but I don't see for sure how the energy level of at least the electrons doesn't increase when I move the vile of liquid helium. Lets say I have it in my hand, then I suddenly move it. The atoms in my hand would repel the atoms in the liquid helium due to electro-magnetism, thus causing them to move, but couldn't I only be moving my hand if my hand had energy to do so, and if I'm using that energy and giving it to the helium, how does greater or lesser amounts of physical force repel the helium atoms at greater or lesser speeds without energy actually being absorbed by the atoms? If I accelerate an atom, does its output of electromagnetic force increase? Or why wouldn't there just be a single speed or force that atoms repel each other at?

Edited May 20, 2011 by steevey

[swansont]

I think I can get how it can still move, but I don't see for sure how the energy level of at least the electrons doesn't increase when I move the vile of liquid helium. Lets say I have it in my hand, then I suddenly move it. The atoms in my hand would repel the atoms in the liquid helium due to electro-magnetism, thus causing them to move, but couldn't I only be moving my hand if my hand had energy to do so, and if I'm using that energy and giving it to the helium, how does greater or lesser amounts of physical force repel the helium atoms at greater or lesser speeds without energy actually being absorbed by the atoms? If I accelerate an atom, does its output of electromagnetic force increase? Or why wouldn't there just be a single speed or force that atoms repel each other at?

 

It's a matter of scale.

 

Atoms at room temperature (~300K) have about 0.025 eV of kinetic energy, on average, so atoms at ~3K will have about 0.00025 eV. If you had a one mole sample and dropped it 1m to the floor, and all of the energy went into increasing the temperature, you'd be spreading 0.04 Joules, or 2.5 x 10^17 eV, among 6.02 x 10^23 atoms. That's 4 x 10^-7 eV per atom, or about a 0.16% increase in their average kinetic energy, i.e. temperature.

 

As far as electronic excitation goes, the first excited state of He is about 20 eV, which is 100,000 times higher than the thermal energy.

[steevey]

 

 

As far as electronic excitation goes, the first excited state of He is about 20 eV, which is 100,000 times higher than the thermal energy.

 

So your trying to say liquid helium doesn't discontinue being liquid helium by moving it because it takes a lot of energy to make it into a higher energy state? How does it still move with a greater force if I move it more violently still on an atomic level, because if I move them really hard, don't they have to have more energy in order move a greater distance?

[swansont]

Bulk motion does not change the temperature.

[steevey]

Bulk motion does not change the temperature.

 

Oh wait, is it something to do with the frequency? Like instead of doing something like throwing it making the individual atoms vibrate faster, its just a push from the electro-magnetic resistance between atoms? But then, how does that energy get transfered through repulsion?

[steevey]

Oh wait, is it something to do with the frequency? Like instead of doing something like throwing it making the individual atoms vibrate faster, its just a push from the electro-magnetic resistance between atoms? But then, how does that energy get transfered through repulsion?

 

In other words, temperature is an increase in energy caused by photons, but something like physical movement is cause by either repultion or attraction between atoms or gravity...