Hacker Read top | best | new | newcomments | leaders | about | bookmarklet login

At the scale of individual particles, heat is movement.


sort by: page size:

> When heated, the atomic structure of the material rearranges

So it does move, just on a smaller scale.


Heat (motion of molecules) is noise (motion of molecules) in this context.

Particles in heat are more active, as in brownian motion puts them allover the place, the cooler things get, the smaller the ripples, the less likely to interact with another particle, by transfering that ripple.

Now in solid materials, that neighbour is always there to distribute any energy to everyone equally. But from solid to gas, there is only the surface and a gases density is lower, so the transfer propability shrinks again.


I thought heat was a form of kinetic energy? Specifically, it is a measure of the kinetic energy of an object's particles, independent of the kinetic energy of the object as a whole. That not accurate?

As explained in the article.

> Temperature measures how fast particles are moving, whereas heat measures the total amount of energy that they transfer.


At the level of particles, isn't "heating" the same as speeding up?

Basically, heat is the thing you say to describe your detection of a transfer of internal energy from an object to its surroundings.

E.g., an object's atoms are vibrating a lot, and you touch it, and that vibration spreads to your atoms, so you say you've noticed "heat" in that object. Or the vibrations are emitting radiation (like infrared light) to you, and the radiation begins vibrating your atoms, so you might say "heat is coming off of that object".

>Heat is energy in transfer to or from a thermodynamic system, by a mechanism that involves the microscopic atomic modes of motion or the corresponding macroscopic properties.

>In the kinetic theory, heat is explained in terms of the microscopic motions and interactions of constituent particles, such as electrons, atoms, and molecules.[57] The immediate meaning of the kinetic energy of the constituent particles is not as heat. It is as a component of internal energy. In microscopic terms, heat is a transfer quantity, and is described by a transport theory, not as steadily localized kinetic energy of particles. Heat transfer arises from temperature gradients or differences, through the diffuse exchange of microscopic kinetic and potential particle energy, by particle collisions and other interactions.[0]

0: https://en.wikipedia.org/wiki/Heat


One which can get absorbed by a single molecule individually as opposed to sound which has to affect large groups of them, increasing movement / heat.

It's _actively_ moving heat from one location to another. What you do with that heat at the other location is another matter.

Hot molecules move faster, it’s just kinetic energy.

They experimentally demonstrated that it takes significantly more energy to move a microparticle the same distance when cooled than the amount of energy it would take when heated.

I don't quite understand. Heat is a measure of the vibrational kinetic energy any individual molecule possesses as it travels along, right? So, shouldn't the maximum temperature just be whatever the unit conversion is for one C-per-oscillation? That is, at no time should a particle be able to be pushed by its vibration into a velocity greater than light, correct?

> On the other hand, cooling at the microscopic level involves the release of energy from individual particles, resulting in a dampening of their motion. This process corresponds to the system losing energy, leading to a decrease in the intensity of particle movement.

It actually makes sense, doesn’t it? Heating the object adds energy constructively. In cooling, energy removed from one particle may in fact be absorbed again by neighboring particles, so it is not ‘efficient’. So I’d venture a guess at saying the object cools from outside until it is entirely cooled.


But isn't that passing on of energy from one particle to the next, just conduction? Why wouldn't it apply in the same way when heating?

Temperature is high but total heat isn't remarkable. The atoms are moving very fast but there aren't many of them.

Thank you, but what, specifically is "heat"

What property of matter is 'heat'


Thank you, but what, specifically is "heat"

What property of matter is 'heat'


And thermal energy is mostly kinetic energy.

Heat dissipation.
next

Legal | privacy