What is heat?

[swansont]

Temperature describes the average heat or thermal energy

This is the part that's wrong. If you have to objects at the same temperature, no heat will flow. However, the objects have a temperature and thermal energy.

 

One of the big problems in all of this is that someone decided to call C the heat capacity, and that leads to certain conceptual errors.

 

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heat.html#c1

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatra.html

 

"Heat may be defined as energy in transit from a high temperature object to a lower temperature object. An object does not possess "heat"; the appropriate term for the microscopic energy in an object is internal energy. The internal energy may be increased by transferring energy to the object from a higher temperature (hotter) object - this is properly called heating."

 

"Heat is Kinetic Energy"

http://www.vias.org/physics/bk2_03_02.html

 

"Thermal energy (heat) is kinetic energy"

http://mineral.gly.bris.ac.uk/geochemistry/pdflectures/Thermodynamics1.pdf

 

"Heat (or thermal) energy is kinetic energy due to motion of atoms and molecules."

http://okfirst.mesonet.org/train/meteorology/HeatTransfer.html

 

Stating or pointing out "It's the transfer" does not negate the fact that heat or thermal energy is kinetic energy.

 

The word "transfer" itself implies motion or kinetic energy. So sure, yeah, it is "the transfer"

 

A transfer of kinetic energy to my skin is interpreted by my nervous system as "heat" but there is no actual "heat particle" or "Heat" as such - as a thing in itself - being transferred. There is no such thing.

 

You cannot separate "Heat" and put it in a bottle.

 

You've cited a geochemist and someone who (in equating heat with temperature) says "Yes, it is at least theoretically possible to remove all the heat from an object." The former is misinformed, and as for the latter, if you are of the opinion that someone who thinks you can violate the third law of thermodynamics is a trusted source, well, go for it.

 

Meanwhile, in physics, heat is as is defined in the hyperphysics links I just gave.

[spin-1/2-nuclei]

This is the part that's wrong. If you have to objects at the same temperature, no heat will flow. However, the objects have a temperature and thermal energy.

It's a little distressing that you are ignoring integral parts of my previous posts.

I never said two objects of the same temperature would have a transfer of heat.. in fact I said the exact opposite of that. Below is what I said.

 

quoting me:

 

Temperature describes the average heat or thermal energy (this implies of a system, i.e. it is clear when I go on to say).

 

Thermal energy can be transferred by conduction (transfer of energy from one molecule to another), convection (movement of heat by a liquid or a gas), or radiation (transfer of heat by electromagnetic waves).

 

and then I also say

 

Thus "heat" is the transfer or flow of energy from one object to another. Or rather, one area of higher energy to one area of lower energy. So, in this very literal definition of heat, one can say that a single particle (if and only if it existed in isolation in the vacuum) cannot posses "heat", THAT DOES NOT MEAN THAT IT CANNOT POSSESS KINETIC ENERGY. To suggest that there is no correlation between kinetic energy and heat is a descent into ridiculousness that will result in a significant waste of the time you spend studying these concepts.

 

The argument between the terms heat and temperature (while valid on a purely theoretical level) is really only saying that, because there would be nothing there to "observe" the heat - i.e. - the heat would not have anything to transfer to it would not exist. This in my opinion, while a useful academic point, is irrelevant when beginners are looking at the real world definitions of heat and what produces "heat" in molecules and other every day objects.

 

and quoting me again:

 

Heat is the transfer of energy from one object to another. Temperature describes the average heat or thermal energy (you've also said this). Thermal energy can be transferred by conduction (transfer of energy from one molecule to another), convection (movement of heat by a liquid or a gas), or radiation (transfer of heat by electromagnetic waves)

 

====================

 

So unless you are trying to say that all atoms or molecules in a system have the exact same temperature, temperature as I said before describes the average heat or thermal energy (of the system) as is implied (especially when reading the rest of my posts)

 

That being said, I have no intention of getting in to a discussion about the definition of "heat" vs. "temperature". It's a ridiculous circular argument that detracts from the original points.

 

My inflexible, and formal position on this issue is: heat is the transfer of energy from one object to another & only in the most ridiculous of situations does a discussion about the hotness (i.e. the temperature) of heat need to be undertaken to understand how molecular motion - i.e. - kinetic energy gives rise to temperature - which in turn gives rise to heat via the transfer of energy from one object to another as stated before.

 

In the 19th century physics defined temperature as the measure of a system's kinetic energy:

 

Now-a-days temperature is expressed as a relationship between the change in the internal energy, U, and the change in entropy, S, of a system. 1/T = dS/dU, but I already covered this in the chemistry thread earlier so I will just repost that here:

 

again quoting me:

 

So why then does kinetic stability decrease with increasing temperature? Well this becomes more apparent when we relate temperature to entropy. We can do so via

T^-1 = (d/d(E))x(S(E)).. you can see that when temperature increases the entropy of the system also increases.

=========

Thus, with an ideal gas as the internal energy increases the entropy increases. This is because the temperature is nearly always positive (unless we are talking about special conditions which arise in lasers, which we are not)

 

Therefore,

Unless you're planning to explain to me how heat can arise in any system without kinetic energy I'm not interested in debating the definitions of temperature or heat.

 

Cheers

 

So you say heat is transfer or flow, not thermal energy. Now I got your point. In that case, the question I would have asked is "what is thermal energy?" Is it just kinetic energy or does it exist in any other form. I mean whether the atoms of gas have thermal energy in addition to the kinetic energy.

 

and to get back on topic and answer this question for you since that should be the actual focus of this discussion..

There is such a thing called heat capacity:

 

That is to say, when heat - i.e. - thermal energy - is introduced into a system it can be converted to either

a.) kinetic energy

b.) and other forms of internal energy that are specific to the material. This has a lot to do with the chemical composition of the material, it's geometric structure, etc.

Whatever amount of heat is converted to kinetic energy will cause a rise in the temperature of that material. The heat that is introduced deltaQ, divided by the observed temperature change is the heat capacity of the material.

 

Therefore, even the definition of heat capacity is not free from the use of the word temperature. We can even go so far as to talk about the specific heat of a substance, which basically is the amount of heat necessary to increase the temperature by one unit of measurement, whatever unit of measurement you're using.. I'm going to go with K for the hell of it.. either way we're still not escaping things like temperature and molecular motion (i.e. kinetic energy) when we talk about "heat". Nor, is the incorporation of concepts like temperature and kinetic energy somehow detracting from or in anyway stating that "heat" is anything but the measure of the transfer of thermal energy from one object (of higher energy - hot) to another object of (lower energy - cold). In this case "energy" refers to kinetic energy.

 

When someone explains to you how they got heat to transfer from a "hot" object to a "cold" object - without utilizing temperature as the average measure of the kinetic energy to determine which of the objects was in fact hotter or colder then I will be all ears.

 

so,

 

At the end of the day if you want to know what heat is, I'd suggest you obtain a physics review article on the definition of temperature vs. heat, and decide for yourself. If you don't have access to Sci-Finder or the like try a good university library with graduate level physics books.

 

When you read one of those sources you will find that the authors describe heat and temperature in the following ways:

 

Statistical physics/mechanis describes temperature in terms of entropy, and it is a microscopic definition...

 

Entropy describes the disorder of a system, that is to say entropy is the measure of the degrees of freedom of the system, and it increases as the logarithm of the number of different options the system has to organize itself, i.e. the number of degrees of freedom.

Thermodynamics uses a macroscopic definition of temperature that correlates work and heat.

 

In the most basic undergrad physics temperature is expressed in units of energy.

 

For experiments conducted, in the real world (the ideal conditions obtained in the vacuum are so hard to come by in the lab), both the macroscopic and microscopic definitions of temperature are correlated via the Boltzmann constant (a proportionality factor that scales temperature to the microscopic average kinetic energy).

 

So, as I have been saying and saying - temperature is a measure of the "hotness" of the heat which is a measure of thermal energy transfered from one object to another..

 

hopefully this was helpful,

Cheers

Edited August 18, 2011 by spin-1/2-nuclei

[pantheory]

 

Since I think that reality is relatively simple, I believe this characterization is often wrong.

my quote

 

Please explain a little bit.

your request

 

This is the classical physics section so I cannot explain the details in this thread, but I believe that all of reality consists of just one particle with one innate mechanical force and nothing more. Accordingly there is nothing complicated in reality. You can ask questions concerning the details if you wish in the speculation forum, "alternative to the Big Bang model." It is based on my 400 hundred page book/ theory of theoretical physics and cosmology.

 

One could. But if you believe you know a simple valid perspective/ definition, you could simply provide it .

my quote

//

I just pointed out 'the absence of a simple valid perspective/ definition'. ..

your quote

 

Concerning this thread I think the Kinetic Theory of Heat simply explains the "what is heat" question. No matter what the question in physics I believe the answer is relatively simple. Of course I do not know all the correct answers to everything but can give the answers (which I consider valid) according to my model.

Edited August 18, 2011 by pantheory

[J.C.MacSwell]

 

Temperature describes the average heat or thermal energy

 

 

What exactly does this mean?

 

 

Thus "heat" is the transfer or flow of energy from one object to another. Or rather, one area of higher energy to one area of lower energy.

 

 

...and this?

 

You may know exactly what you mean, and that may be correct...but I don't know that. All I know is that is that it can be clearly wrong if I take it literally.

 

Even if you mean thermal energy. Cold steel will not heat warm insulation.

Edited August 19, 2011 by J.C.MacSwell

[Tom Booth]

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heat.html#c1

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatra.html

 

"Heat may be defined as energy in transit from a high temperature object to a lower temperature object. An object does not possess "heat"; the appropriate term for the microscopic energy in an object is internal energy. The internal energy may be increased by transferring energy to the object from a higher temperature (hotter) object - this is properly called heating."

 

(...)

Meanwhile, in physics, heat is as is defined in the hyperphysics links I just gave.

 

OK sticking by your trusted source to quote again more specifically:

 

"An object does not possess "heat"; the appropriate term for the microscopic energy in an object is internal energy."

 

Further down the page:

 

"To describe the energy that a high temperature object has, it is not a correct use of the word heat to say that the object "possesses heat" - it is better to say that it possesses internal energy as a result of its molecular motion. The word heat is better reserved to describe the process of transfer of energy from a high temperature object to a lower temperature one. Surely you can take an object at low internal energy and raise it to higher internal energy by heating it. But you can also increase its internal energy by doing work on it, and since the internal energy of a high temperature object resides in random motion of the molecules, you can't tell which mechanism was used to give it that energy."

 

 

This author says: "The word heat is better reserved to describe the process of transfer of energy from a high temperature object to a lower temperature one."

 

and also:

 

"Don't refer to the "heat in a body", or say "this object has twice as much heat as that body". He also objects to the use of the vague term "thermal energy" and to the use of the word "heat" as a verb, because they feed the misconceptions, but it is hard to avoid those terms. He would counsel the introduction and use of the concept of internal energy as quickly as possible."

 

More semantics.

 

Take this statement: ""The word heat is better reserved to describe the process of transfer of energy..."

 

What type of "energy" specifically ?

 

And again:

 

"it is not a correct use of the word heat to say that the object "possesses heat" - it is better to say that it possesses internal energy..."

 

Again, what type of energy are we talking about when saying "internal energy" ?

 

The author states "molecular motion" and / or "random motion of the molecules" which equates to kinetic energy, does it not ?

 

I don't feel a need to apologize for my sources, they were picked at random from a cloud of search results simply to show that it is commonly understood by virtually everyone with an opinion on the subject that heat (thermal energy) is really kinetic energy or molecular motion.

 

If as you stated earlier that LIGHT IS heat then please explain how a laser can cool atoms to near absolute zero.

 

If light were heat there would be no way to cool anything by bombarding it with laser light as demonstrated with the Bose Einstein condensate experiments cited earlier:

 

http://www.nobelprize.org/nobel_prizes/physics/laureates/1997/index.html

 

How does laser cooling work ?

 

"...the kinetic energy of the atom will be reduced. Since the temperature of an ensemble of atoms is a measure of the random internal kinetic energy, this is equivalent to cooling the atoms."

 

http://en.wikipedia.org/wiki/Laser_cooling

 

Bottom line in my opinion: Assuming the kinetic theory of heat has led to successful experimental results. It has a good track record in terms of predictability. It leads to predictable real world observable effects such as laser cooling which IMO would be impossible if the theory were false or certainly would not be possible if light itself were heat.

 

Sure, light carries energy that can, under certain circumstances be converted into "HEAT" (i.e. an increase in kinetic energy) but light is not heat.

 

"Heat", or an increase in kinetic energy can take place in numerous other ways I believe, in the total absence of light. can it not ?

 

If light were heat then there would be no possibility of "heat" transfer without light. As far as I'm aware there is no such necessity to have light present to effect "heat" transfer. All you need is to have one molecule bump against another (i.e. transfer kinetic energy).

 

Such a transfer could be one air or gas molecule against another. As far as I'm aware there is no light involved in such a transfer of kinetic (heat) energy.

 

Perhaps you missed this page from your source:

 

http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/kinthe.html

 

Or this one:

 

http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/kintem.html

[spin-1/2-nuclei]

I have to be honest I am really disappointed in this thread. I came here to answer a question about the definition of heat, which after further reading was clearly more of a request for information about how heat arises. In all the lengthy posts I've made on this topic, the only thing anyone really cares about are.

 

a.) two statements taken out of context

and

b.) whether or not it is okay to make assumptions from statements found in posts - that were not read in their entirety - or if it was read in it's entirety - whether or not it is okay to make assumptions about statements that clearly contradict other statements made in the same post.

 

This literally reminds me of kindergarden. I don't care about other people's assumptions and how they came about when I clearly stated the opposite in my post. I think that is fair.

 

Moreover, I really don't want to talk about nonsense. To be quite frank, I've already learned this stuff and I am more than happy to discuss concepts, but when a difference in position has been firmly stated - as I did the previous post - and when I've made statements that directly contradict what I am accused of saying - in the same post the "offending" quoted statement is lifted from..

 

and then having to talk about those statements - despite clear context being given to those statements in numerous lengthy posts - leads me to the conclusion that right now the purpose of this discussion is not science.

So, if you've read nothing else in this post please read: I don't want to discuss anything other than scientific concepts and I am more than happy to discuss different positions and perspectives, but I do not care to discuss semantics and preferences for information delivery (that is what questions and reading posts in their entirety to obtain context are for).. if you don't care enough about what I am saying to do one of those two things, then fair enough - but please don't waste my time by engaging me with responses to those posts.

 

What exactly does this mean?

 

Seriously?

It means that temperature is the measure of the average kinetic energy - which is the same as the thermal energy - and this thermal energy - i.e. heat (when being transfered) - i.e. the "hotness" is measured by temperature.

"Kinetic energy is a general term describing the energy associated with the motion of objects (large or small objects). You can calculate the kinetic energy of an object of mass m with a velocity (speed) v from the formula K.E. = 1/2 mv^2. Thermal energy refers to the kinetic energy of the microscopic particles (atoms and molecules) that make up all samples of matter - i.e. all objects. When you add heat to an object, you increase the temperature of the object (usually) and that heat increases the kinetic energy of the molecules that comprise that object. In fact, temperature is a measure of the average kinetic energy of the microscopic particles that make up an object.

Hope this helps....

 

Dr. Brown " - http://www.newton.dep.anl.gov/askasci/chem99/chem99045.htm

 

"Heat is the total energy of molecular motion in a substance while temperature is a measure of the average energy of molecular motion in a substance. Heat energy depends on the speed of the particles, the number of particles (the size or mass), and the type of particles in an object. Temperature does not depend on the size or type of object. For example, the temperature of a small cup of water might be the same as the temperature of a large tub of water, but the tub of water has more heat because it has more water and thus more total thermal energy." - http://coolcosmos.ipac.caltech.edu/cosmic_classroom/light_lessons/thermal/differ.html

 

"kinetic - energy of motion

potential - stored energy

gravitational

elastic

chemical - energy of chemical bonds and reactions

thermal - energy of heat - disorder" - http://www.uccs.edu/~tchriste/courses/PES100/100lectures/heat.html

 

"Thermal energy is related to the temperature of matter. For a given material and mass, the higher the temperature, the greater its thermal energy. Heat transfer is a study of the exchange of thermal energy through a body or between bodies which occurs when there is a temperature difference. When two bodies are at different temperatures, thermal energy transfers from the one with higher temperature to the one with lower temperature. Heat always transfers from hot to cold." - http://www.tufts.edu/as/tampl/en43/lecture_notes/ch1.html

 

So, from all of that we can conclude - as I have been saying.. heat is the transfer of energy from one object to another - it transfers from a place of higher energy (thermal/kinetic) to a place of lower energy (thermal/kinetic).

From his own source:

Thermal energy = "The average translational kinetic energy possessed by free particles given by equipartition of energy is sometimes called the thermal energy per particle. It is useful in making judgements about whether the internal energy possessed by a system of particles will be sufficient to cause other phenomena. It is also useful for comparisons of other types of energy possessed by a particle to that which it possesses simply as a result of its temperature." - http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/eqpar.html#c2

and

 

"The kinetic temperature is the variable needed for subjects like heat transfer, because it is the translational kinetic energy which leads to energy transfer from a hot area (larger kinetic temperature, higher molecular speeds) to a cold area (lower molecular speeds) in direct collisional transfer." - http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/kintem.html

 

 

Thus, heat flows from hot (high thermal energy) to cold (low thermal energy) objects until they have the same thermal energy.... and we already know that thermal energy = kinetic energy when we are speaking about the motion of molecules [as I have been saying and saying]..

 

"Microscopically, the thermal energy is the kinetic energy of a system's constituent particles, which may be atoms, molecules, electrons, or particles in plasmas. It originates from the individually random, or disordered, motion of particles in a large ensemble. The thermal energy is equally partitioned between all available quadratic degrees of freedom of the particles. These degrees of freedom may include pure translational motion in fluids, normal modes of vibrations, such as intermolecular vibrations or crystal lattice vibrations, or rotational states. In general, the availability of any such degrees of freedom is a function of the energy in the system, and therefore depends on the temperature." - http://en.wikipedia.org/wiki/Thermal_energy

 

...and this?

 

You may know exactly what you mean, and that may be correct...but I don't know that. All I know is that is that it can be clearly wrong if I take it literally.

 

I disagree, I think other people might too, especially if they read everything I said. That is what context is for..

 

'spin-1/2-nuclei' timestamp='1313692479' post='622641']

Thus "heat" is the transfer or flow of energy from one object to another. Or rather, one area of higher energy to one area of lower energy. So, in this very literal definition of heat, one can say that a single particle (if and only if it existed in isolation in the vacuum) cannot posses "heat", THAT DOES NOT MEAN THAT IT CANNOT POSSESS KINETIC ENERGY. To suggest that there is no correlation between kinetic energy and heat is a descent into ridiculousness that will result in a significant waste of the time you spend studying these concepts.

 

The argument between the terms heat and temperature (while valid on a purely theoretical level) is really only saying that, because there would be nothing there to "observe" the heat - i.e. - the heat would not have anything to transfer to it would not exist. This in my opinion, while a useful academic point, is irrelevant when beginners are looking at the real world definitions of heat and what produces "heat" in molecules and other every day objects.

So, if for whatever reason you don't agree with what's been said above, please take that up with the sources (numerous university websites, etc) and not me.

 

Cheers

Edited August 19, 2011 by spin-1/2-nuclei

[J.C.MacSwell]

Absolutely not. Heat is not kinetic energy, nor is temperature a measure of heat.

 

 

 

Heat is transfer of a type of kinetic energy. Is it not?

 

Not disagreeing with your statement at all. Just for clarity.

 

Note that Wiki has a Heat (disambiguation) heading.

 

Heat, in physics, is energy which is spontaneously flowing from an object with a high temperature to an object with a lower temperature.

Heat may also refer to (bolding mine):

 

"Thermal energy, the sum of a body's latent and sensible forms of energy (sometimes confused with "heat") "

[edit]

 

I know that in engineering, and sometimes physics, this confusion/ambiguity is fairly common.

 

 

I disagree, I think other people might too, especially if they read everything I said. That is what context is for..[/b]

 

 

 

Hi Spin

 

I'm sorry if that is upsetting. And honestly I have not read to the point of understand everything you have said.

 

But to me that is what semantics are for. At this point I honestly don't know if you understand your statements... though I suspect that you might.

 

I am sure others would agree with you, though I bet you would be disappointed in some of them when you found out why.

 

Microscopically, the thermal energy is the kinetic energy of a system's constituent particles, which may be atoms, molecules, electrons, or particles in plasmas. It originates from the individually random, or disordered, motion of particles in a large ensemble. The thermal energy is equally partitioned between all available quadratic degrees of freedom of the particles. These degrees of freedom may include pure translational motion in fluids, normal modes of vibrations, such as intermolecular vibrations or crystal lattice vibrations, or rotational states. In general, the availability of any such degrees of freedom is a function of the energy in the system, and therefore depends on the temperature.

 

 

That is your quote from Wiki.

 

It is wrong. The bolded is not all thermal energy. In what context can it be considered correct?

 

 

 

 

Seriously?

It means that temperature is the measure of the average kinetic energy - which is the same as the thermal energy - and this thermal energy - i.e. heat (when being transfered) - i.e. the "hotness" is measured by temperature.

 

 

Seriously? Is a 95mph fastball at a higher temperature than it was prior to being thrown?

Edited August 19, 2011 by J.C.MacSwell

[Tom Booth]

 

 

Seriously? Is a 95mph fastball at a higher temperature than it was prior to being thrown?

 

Theoretically, I believe that is supposed to be the case as it has had "work" done upon it. The rise in temperature may be infinitesimal in this case but you have pressure from fingers against the ball squeezing the ball, friction against the hand and against the air transferring energy etc.

 

If you compress a gas the temperature rises in part due to work having been done by the piston or whatever in the compressor pushing the gas. This is also true of a solid. Stand on a chair and the extra weight will raise the temperature of the chair slightly. A window fan raises the temperature of the air it pushes as the fan is doing work against the air etc. etc.

 

In ordinary circumstances temperatures will equalize quickly but under controlled conditions such changes can be and have been measured.

 

http://en.wikipedia.org/wiki/Mechanical_equivalent_of_heat

 

Since there is no such thing as heat:

 

I don't know how I'm going to cook my beans or what I'm going to do to keep warm this winter.

 

If you carry a wooden wagon wheel to the top of a hill it has "potential energy" to roll back down right ?

 

If you break the wagon wheel up and use it to build a camp fire on the top of the hill... what happened to the "potential energy" ?

 

Where can I find the "potential energy" that was "stored" in the wheel or any such object; bowling ball, water balloon car tire or whatever; carried to the top of a hill ?

 

I would submit that there is no such thing as "potential energy" any more than there is "heat energy". They are just convenient fictions.

[finiter]

That is to say, when heat - i.e. - thermal energy - is introduced into a system it can be converted to either

a.) kinetic energy

b.) and other forms of internal energy that are specific to the material. This has a lot to do with the chemical composition of the material, it's geometric structure, etc.

Whatever amount of heat is converted to kinetic energy will cause a rise in the temperature of that material. The heat that is introduced deltaQ, divided by the observed temperature change is the heat capacity of the material.

 

Therefore, even the definition of heat capacity is not free from the use of the word temperature. We can even go so far as to talk about the specific heat of a substance, which basically is the amount of heat necessary to increase the temperature by one unit of measurement, whatever unit of measurement you're using..

 

That part is clear. However, I would like to know whether it is 'the kinetic part' or 'the rest' that causes the increase in temperature. The specific heat is the energy required to increase the temperature by one degree. Naturally, I think that internal energy 'other than the kinetic energy' can be referred to as 'thermal energy' or 'heat energy' of the body.

[spin-1/2-nuclei]

Wow JC,

 

You'd rather insult me than actually back your position up with first principles.

 

Your example is ridiculous. There is a difference between the macroscopic and microscopic level.

 

Insulting me doesn't make the nonsense some people are pushing here any more accurate.

 

Briefly,

 

Yes a tennis ball traveling through the air at 95 mph has a different surface temperature than an identical tennis ball, which is sitting still. For many reasons, it's kinetic energy being one of them.

 

A molecule moving at speed X, which is 10 times slower than the identical molecule moving at speed Y, will have a different temperature.

 

Kinetic energy = molecular movement = temperature = a measure of the "hotness" i.e. heat transfer...

 

I'm sorry that you guys seem unwilling/unable to understand this basic concept but this degenerated into a waste of my time a long time ago. Not to mention I personally find insults in stead of facts and logic a pointless way to have a discussion, unless of course one argues for the sake of arguing, which I do not.

 

Thus if you guys want to believe that heat and kinetic energy are mutually exclusive - as in you can get one without the other- be my guest... I don't cater to bullies or egomaniacs. It takes time to learn these concepts beyond the basic high school introductory course. I'd suggest some people actually put in the effort to understanding kinetic energy, entropy (its relationship to the movement of molecules), temperature, and the concept of thermal energy as it relates to kinetic energy.

 

ALL OTHER POSTS ADRESSED TO ME IN THIS THREAD WHICH ARE DEVOID OF VALID SCIENTIFIC QUESTION OR A VALID POINT WILL BE IGNORED.

[finiter]

This is the classical physics section so I cannot explain the details in this thread, but I believe that all of reality consists of just one particle with one innate mechanical force and nothing more. Accordingly there is nothing complicated in reality. You can ask questions concerning the details if you wish in the speculation forum, "alternative to the Big Bang model."

Surely. I will meet you in that forum.

 

Well for one thing, the scenario you describe is impossible. In such a situation, the "average kinetic energy" in relation to volume at least could not be the same.

Why is it impossible? Average kinetic energy in relation to volume is not average kinetic energy. That is, you are proposing that volume is also a factor (in addition to the kinetic energy) that decides the temperature. (Incidentally, such a proposal is what seems right to me.) Did you actually mean that?

[spin-1/2-nuclei]

That part is clear. However, I would like to know whether it is 'the kinetic part' or 'the rest' that causes the increase in temperature. The specific heat is the energy required to increase the temperature by one degree. Naturally, I think that internal energy 'other than the kinetic energy' can be referred to as 'thermal energy' or 'heat energy' of the body.

 

Hello,

 

yes in the real world kinetic energy is responsible for the increase in temperature..

 

But, in this thread, I think the semantics argument is causing too much confusion, so this is what happens without the semantics:

 

1. molecules have movement and this movement results in an increase in energy, to avoid semantics let's call it E1

2. this energy - E1 - "stored" in molecules at high energy (i.e. high temp) is transfered to other molecules with lower energy (i.e. colder) via a process we will call "transference"

 

3. In this process called "transference" the E1 has a measurable energy ET (for energy of transfer to avoid using the term heat) that can be felt by you if you touch a higher energy object that has more energy than you and it's ET is transfered to you and the intensity of that transfer is measured by what we will call the "Ouch factor - to avoid using the term temperature).

 

4. This "Ouch factor" is separate from the ET although these things are all related as in the increase in one will increase the other and so on and so forth without - exceptional extenuating circumstances that are not found in the everyday - so we will ignore those for now just as airline pilots ignore combat maneuvers during their training for commercial flight.

 

5. Once the ET is fully transfered to other locations of lower energy - the "Ouch factor" you experience when touching all the objects in the system will be the same.. i.e. "ouch factor measured ETEQ - i.e. thermal equilibrium" will have been achieved.

 

6. BEFORE equilibrium is attained, ALL the sub-equilibriums inside each sub-system of the macrosystem must be satisfied. That is to say materials have pockets of lower and higher energy - as do molecules. It takes energy to rotate chemical bonds, and adopting certain configurations (without the making or breaking of covalent bonds) is a continuous process in the real word.. that is to say molecules are always moving.

 

The movement - i.e. the E1 (which is kinetic energy in the real world) is derived from all of these different movements.. and this is how entropy - which I will call the "chaotic factor" here to avoid argument - is related to molecular movement. On the microscopic level there is a huge connection with the E1 (kinetic energy), "the chaotic factor" (Entropy), and the "ouch factor" (temperature)

 

7. So, once ET arrives at the other destinations it can be broken up into many different "types" of energy, which is just a way of saying the molecule that ET arrives at can use ET to either increase the molecular motions (E1/kinetic energy) which will increase the "ouch factor" as well as the intensity of the ET should it want to transfer it's energy to another molecule of lower energy in the form of "transference"/heat..

 

What happens to ET once it transfers from one molecule to another will depend on the environment. All systems strive to reach equilibrium - and so depending on what is best for the system the outcome of an ET transfer from one molecule in a system to another - or one object in the macroscale to another - will not be the same.

 

That is to say transferring ET/heat from one object to another in the macroscale will not always have the same results. This is because objects are made out of different materials and different materials are made out of either different molecules - or in the cases of materials made out of the same molecules with different connectivity, different geometric configurations).. All this really means is that connecting atoms in different ways increase and decreases the rigidity in those molecular and supramolecular structures, which in turn results in differing intensities of E1/kinetic energy when ET/heat/thermal energy is applied to the system, which results in different "ouch factors" from the same intensity of ET/heat...

 

ET can also be used to make or break chemical bonds (which depending on the situation will either reduce the "ouch factor" or increase the "ouch factor", etc. This is because E1 refers to all the movement in the system and chemical reactions can increase entropy "chaotic factor", which will result in an increase in the "ouch factor" which I described mathematically in another post.. and as I said earlier, molecular movement and entropy "chaotic factor" are very closely related, this is simply because maximum entropy "chaotic factor" is achieved when the molecules in the system are as evenly distributed as they can be - that is to say each molecule has the most space it can get - and that is just another way of saying the more space a molecule has the more degrees of freedom it has (remember when molecules get too close to each other repulsive forces and other attractive intermolecular forces act to lower the entropy "chaotic factor" of the system) - which is yet another way of saying (at the macroscopic level) stuff with more space to move without collision moves more.

 

Thus,

molecules with the same "E1"/kinetic energy will have the same "ET"/heat/thermal energy.

 

Once "ET"/thermal energy leaves the high energy molecule A via "transference" and goes to lower energy molecule B and C, molecule B may or may not have the same resulting "E1"/kinetic energy. It will depend on the initial "E1"/kinetic energy of both B and C, their chemical composition, geometric configurations, and any other environmental parameters that interact with the system. The "chaotic factor"/entropy can be very different even between identical molecules depending on their environment - as explained above..

 

So, molecular motion produces an energy, that is then transfered to other molecules - of lower energy - in the form of another "type" of energy. The intensity of that other "type" of energy is proportional to the energy of the motion (even if that energy is not doing the same thing), and this is observed/measured by the intensity of the higher energy system in respect to the low energy system such that during the transfer of said energy ("ouch factor"/temperatureof the aforementioned energy will be proportional to the energy actually transferred. Which is not always the same as the energy that originated as systems - which in the real world do not exist in a vacuum - distribute energy as equally as possible throughout their sub-systems (from the perspective of what bring the system to the lowest possible energy, i.e. its most stable existence).. and you can think of this as many mini-equilibriums adding up to one macroequilibrium which describes the total energy of the entire system.

 

Hopefully this helps..

Cheers

Edited August 19, 2011 by spin-1/2-nuclei

[swansont]

It's a little distressing that you are ignoring integral parts of my previous posts.

 

 

I didn't ignore them. I didn't notice a problem with them. But the part where you equated heat and temperature? I do have a problem with that, which is why I posted my response.

 

Heat is transfer of a type of kinetic energy. Is it not?

 

Not disagreeing with your statement at all. Just for clarity.

 

Depends on two things: whether you call photon energy kinetic energy, and how you use the term. As I think I explained earlier, heat can refer to the energy (Q) or the process.

 

Note that Wiki has a Heat (disambiguation) heading.

 

Heat, in physics, is energy which is spontaneously flowing from an object with a high temperature to an object with a lower temperature.

Heat may also refer to (bolding mine):

 

"Thermal energy, the sum of a body's latent and sensible forms of energy (sometimes confused with "heat") "

[edit]

 

I know that in engineering, and sometimes physics, this confusion/ambiguity is fairly common.

 

It is common. It is also sloppy, and physicists are not blameless in all of this. Again, we are hamstrung by use of terms like heat capacity and latent heat, which have different (and confusing) implications.

 

I don't feel a need to apologize for my sources, they were picked at random from a cloud of search results simply to show that it is commonly understood by virtually everyone with an opinion on the subject that heat (thermal energy) is really kinetic energy or molecular motion.

There are numerous terms that are commonly understood to mean something, but have a very specific meaning (and often contradicted by the common one) in science. Coincidence is a good one. Even acceleration has a different meaning in lay use.

 

If as you stated earlier that LIGHT IS heat then please explain how a laser can cool atoms to near absolute zero.

 

I didn't say "light is heat". I said the light from the sun is heat. It's a very important distinction — the sun is emitting blackbody radiation because it's a thermal source and much hotter than its surroundings. A laser is not a thermal source — it emits a very narrow range of frequencies and is not at all like a blackbody.

 

In thermodynamic terms, the reason lasers can cool atoms can be seen by looking at the Helmholtz (or Gibbs) free energy: the laser has a very low entropy, and the scattered light has a much higher entropy, which is how the energy of the atoms is reduced.

 

 

Sure, light carries energy that can, under certain circumstances be converted into "HEAT" (i.e. an increase in kinetic energy) but light is not heat.

 

At this point all I can do is point you to a physics textbook or class and suggest you pay attention to where they talk about the methods and details of heat transfer: conduction, convection and radiation.

[spin-1/2-nuclei]

Why is it impossible? Average kinetic energy in relation to volume is not average kinetic energy. That is, you are proposing that volume is also a factor (in addition to the kinetic energy) that decides the temperature. (Incidentally, such a proposal is what seems right to me.) Did you actually mean that?

 

Apples and oranges....

 

1. For starters the macroscopic level and the microscopic level are not the same. You can't shake your hand really fast and then say "see! there is no increase in temperature so kinetic energy does not increase temperature" - I mean - LOL!

 

The environment determines how energy will be used and what it will be converted into. What many people fail to understand here is energy is energy and these arbitrary definitions of energy like (thermal/kinetic) are more to help visualize what is going on and less meant to actually outline a "different/better/worse" kind of energy.

 

That being said,

Even on the macroscopic level it is ridiculous to suggest that two identical objects - one moving and one at rest - will have the same temperature if their environments are identical accept for the speed at which they are traveling.

 

If you want to prove to yourself why this is nonsense, even in laymen terms, do a thought experiment to test this out:

take your hand a shake it wildly in the air (it will start to feel cooler), then take your hands and rub them together (it will start to feel warmer).

 

In the first part, your hand cools down due to the loss of kinetic energy as a result of the work being done by the system (your hand) on the air molecules. So in this case the kinetic energy of the air molecules has increased, thus their temperature has increased while the kinetic energy of your hand has decreased since it was transfered to the air molecules in the form of heat and as a result your hand feels cooler while you are moving it wildly through the air.

 

In the second part the kinetic energy of your hands being rubbed together is being converted - via friction - into thermal energy/heat - that is transfered back to your hands from one another and the work being done on the system is coming from the movement of your arms etc [so if we just consider the system of your two hands rubbing together and everything else as external energy sources it becomes easy to comprehend].

 

Thus I maintain that an increase in kinetic energy = an increase in temperature.. all day everyday..

 

hopefully this was helpful, but I'm checking out of this thread permanently since my tolerance for psuedoscience has been exceeded.

You seem like a very smart and inquisitive person. I think you will have no trouble understanding these concepts if you crack open an undergrad engineering physics/calculus based physics text book. My honest suggesting is to avoid learning concepts based on information obtained from internet forums that degenerate into nonsense. If you don't have a solid understanding of the subject you will not be able to distinguish the valid scientific concepts, from the bs pushed by crackpots, and you might confuse valid concepts if they are wrapped up in semantics.

 

So my advice is to find a naming convention that works the best for you to understand these concepts. The age old argument of heat energy vs. thermal energy doesn't really mean anything on the ground, and you can understand the concepts yourself if you take the time to get the information you're requesting from the right sources..

 

that's my two cents..

Best of luck with your studies

Cheers

[J.C.MacSwell]

Wow JC,

 

You'd rather insult me than actually back your position up with first principles.

 

Your example is ridiculous. There is a difference between the macroscopic and microscopic level.

 

Insulting me doesn't make the nonsense some people are pushing here any more accurate.

 

Briefly,

 

Yes a tennis ball traveling through the air at 95 mph has a different surface temperature than an identical tennis ball, which is sitting still. For many reasons, it's kinetic energy being one of them.

 

A molecule moving at speed X, which is 10 times slower than the identical molecule moving at speed Y, will have a different temperature.

 

Kinetic energy = molecular movement = temperature = a measure of the "hotness" i.e. heat transfer...

 

I'm sorry that you guys seem unwilling/unable to understand this basic concept but this degenerated into a waste of my time a long time ago. Not to mention I personally find insults in stead of facts and logic a pointless way to have a discussion, unless of course one argues for the sake of arguing, which I do not.

 

Thus if you guys want to believe that heat and kinetic energy are mutually exclusive - as in you can get one without the other- be my guest... I don't cater to bullies or egomaniacs. It takes time to learn these concepts beyond the basic high school introductory course. I'd suggest some people actually put in the effort to understanding kinetic energy, entropy (its relationship to the movement of molecules), temperature, and the concept of thermal energy as it relates to kinetic energy.

 

ALL OTHER POSTS ADRESSED TO ME IN THIS THREAD WHICH ARE DEVOID OF VALID SCIENTIFIC QUESTION OR A VALID POINT WILL BE IGNORED.

 

Just to be clear. The translational (and rotational) kinetic energy of the macroscopic object/ball. Do you consider that part of the thermal energy?

 

Apparently you believe it is. Correct me if I am wrong. To me it is an important distinction. Ranting about it, or feeling insulted, does not help make it clear. If it turns out that I am using the wrong definition, I'm fine with that. My ego will be fine.

 

Yours should be as well.

[spin-1/2-nuclei]

@swansont..

 

Seriously?

I know I said I wouldn't address this but I really can't resist. It's just ming boggling..

 

I didn't say heat = temperature...

 

that association only happens in your mind. Which is puzzling since I later said that "heat is the transfer of energy from one object to another, and then went on to say an object of higher energy to an object of lower energy"

 

WHAT I ACTUALLY SAID WAS..

 

temperature describes the average heat or thermal energy. NOT temperature is the average heat or thermal energy.

 

"de·scribe (d-skrb)

tr.v. de·scribed, de·scrib·ing, de·scribes

1. To give an account of in speech or writing. <----- is temperature not an account of the energy transfered from one object of higher energy to another of lower energy? (I guess you'd like to tell me what the unit of measurement we're currently using corresponds to or what the T is doing in PV=NkT. LOL!

 

2. To convey an idea or impression of; characterize: She described her childhood as a time of wonder and discovery. <--- I guess to you here she is literally saying that the word childhood (and all that implies) is a synonym for two complete different words, both wonder and discovery, thereby merging the individual definitions of all?

 

3. To represent pictorially; depict: Goya's etchings describe the horrors of war in grotesque detail.

4. To trace the form or outline of: describe a circle with a compass." - http://www.thefreedictionary.com/describes

 

It's a shame... now we are also arguing about the semantics of the word describe, which obviously (if you read my post in it's entirety) is interchangeable with the word measure.

 

All of this BS is just sad, because the person who started this thread really ONLY wants to know - HOW - does heat arise. Instead of explaining this to the poster you've decided to go out of your way to make ridiculous arguments about the semantics of the word temperature and heat, in isolation of the context of the posts where the terms were being used. This has resulted us now arguing about the semantics of the word described? Which if read in the full context of my post - obviously - meant measured - and if it wasn't clear to you that time - it SHOULD have been clear to you AFTER THE NUMEROUS POSTS I'VE MADE SINCE THEN..

 

YET, WE ARE STILL ARGUING ABOUT SEMANTICS.. WHY?

 

sigh,

what a colossal waste of time.

 

Just to be clear. The translational (and rotational) kinetic energy of the macroscopic object/ball. Do you consider that part of the thermal energy?

 

Apparently you believe it is. Correct me if I am wrong. To me it is an important distinction.

 

Ranting about it, or feeling insulted, does not help make it clear. If it turns out that I am using the wrong definition, I'm fine with that. My ego will be fine.

 

Yours should be as well.

 

LOL! You call this asking a question about science? My "ego" has no problem with questions or even different opinions, but my patience do have a problem with this:

 

Hi Spin

 

I'm sorry if that is upsetting. And honestly I have not read to the point of understand everything you have said.

 

But to me that is what semantics are for. At this point I honestly don't know if you understand your statements... though I suspect that you might.

 

I am sure others would agree with you, though I bet you would be disappointed in some of them when you found out why.

 

So basically what you are saying here is:

a.) you haven't read everything I've said

b.) you don't understand everything I've said

yet

c.) you're drawing conclusions about it anyway

and

d.) you thought it appropriate to take those conclusions all the way to he point where I don't know what I am talking about.

 

You don't know me (or my qualifications for that matter), you haven't understood what I've said, and yet you are wasting my time by telling me I don't know what I am talking about without having bothered to read/understand everything I've said.

 

Gotta say, that is disappointing, and in regards to your other question.. I already answered it in the numerous posts that you haven't taken the time to read/understand.

 

Thus in lieu of a "rant" which I prefer to call a "desperate plea for people to be reasonable" - I think I will force myself to adhere to my original position and have nothing else to do with this thread. A normal discussion cannot be had like this..

 

Cheers

[J.C.MacSwell]

 

 

 

 

So basically what you are saying here is:

a.) you haven't read everything I've said

b.) you don't understand everything I've said

yet

c.) you're drawing conclusions about it anyway

and

d.) you thought it appropriate to take those conclusions all the way to he point where I don't know what I am talking about.

 

 

a) I didn't say that

b) I told you that

c) actually I haven't, though I've started to guess

d) I hazarded a guess hoping you would clarify

 

Yes or No, does your definition of thermal energy include the macroscopic portions of kinetic energy?

 

Because my definition does not you seem to believe I think kinetic energy and thermal energy must be mutually exclusive.

 

Therefore, is it fair to say?:

 

 

b.) you don't understand everything I've said

yet

c.) you're drawing conclusions about it anyway

 

You talk about semantics like you are above it, and yet blame others for failure to communicate.

 

So again:

 

Yes or No, does your definition of thermal energy include the macroscopic portions of kinetic energy?

[swansont]

@swansont..

 

Seriously?

I know I said I wouldn't address this but I really can't resist. It's just ming boggling..

 

I didn't say heat = temperature...

 

that association only happens in your mind. Which is puzzling since I later said that "heat is the transfer of energy from one object to another, and then went on to say an object of higher energy to an object of lower energy"

 

WHAT I ACTUALLY SAID WAS..

 

temperature describes the average heat or thermal energy. NOT temperature is the average heat or thermal energy.

 

The implication — especially with people reading this without the benefit of a physics background, as is obviously the case here in this thread — is that temperature and heat are directly related and perhaps interchangeable.

 

Basically you seem to be arguing that the statement is not wrong because you got it right somewhere else. Temperature is not the average heat or average thermal energy. Temperature is a measure of the average translational kinetic energy of the constituent particles. Thermal energy is more involved — you include internal energy as well. Heat is transferred energy. Tying them all together like that is misleading at best.

[J.C.MacSwell]

The implication — especially with people reading this without the benefit of a physics background, as is obviously the case here in this thread — is that temperature and heat are directly related and perhaps interchangeable.

 

Basically you seem to be arguing that the statement is not wrong because you got it right somewhere else. Temperature is not the average heat or average thermal energy. Temperature is a measure of the average translational kinetic energy of the constituent particles. Thermal energy is more involved — you include internal energy as well. Heat is transferred energy. Tying them all together like that is misleading at best.

 

From Wiki:

 

"Therefore, temperature is tied directly to the mean kinetic energy of particles moving relative to the center of mass coordinates for that object."

Edited August 19, 2011 by J.C.MacSwell

[spin-1/2-nuclei]

The implication — especially with people reading this without the benefit of a physics background, as is obviously the case here in this thread — is that temperature and heat are directly related and perhaps interchangeable.

 

Basically you seem to be arguing that the statement is not wrong because you got it right somewhere else. Temperature is not the average heat or average thermal energy. Temperature is a measure of the average translational kinetic energy of the constituent particles. Thermal energy is more involved — you include internal energy as well. Heat is transferred energy. Tying them all together like that is misleading at best.

No,

 

I'm saying it's right because its right and that YOUR misinterpretation is both

a) resulting from your confusion of the word describe

As well as your now blantantly obvious misunderstanding on translational energy and thermal energy. They are not mutually exclusive - from your own preferred source read: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/rayj.html#c4

 

"The average translational kinetic energy possessed by free particles given by equipartition of energy is sometimes called the thermal energy per particle.

It is also useful for comparisons of other types of energy possessed by a particle to that which it possesses simply as a result of its temperature."

 

Thus my statement "temperature describes - i.e. - measures - the thermal energy which is the heat - i.e. - heat = translational kinetic energy = the energy being transferred IS accurate semantically according to your own preferred source.

 

I'm sorry, but you're just wrong.

 

I've spent a lot of time on this topic because I'm a scientist and I care about how science is presented to the world. Right now, you don't know what you are talking about and you are over complicating a very basic concept in introductory physics. That is to say, thermal energy is ONLY more complicated / "involved" in your mind and especially as it relates to this topic.

 

Hopefully this helps.

Cheers

 

http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/eqpar.html#c1

 

Here is the correct link to the thermal energy tutorial from your preferred source.

 

Cheers

[hawksmere]

Heat energy (or just heat) is a form of energy which transfers among particles in a substance (or system) by means of kinetic energy of those particle. In other words, under kinetic theory, the heat is transfered by particles bouncing into each other.

[Cap'n Refsmmat]

"The average translational kinetic energy possessed by free particles given by equipartition of energy is sometimes called the thermal energy per particle.

It is also useful for comparisons of other types of energy possessed by a particle to that which it possesses simply as a result of its temperature."

 

Thus my statement "temperature describes - i.e. - measures - the thermal energy which is the heat - i.e. - heat = translational kinetic energy = the energy being transferred IS accurate semantically according to your own preferred source.

Could you point out which part of the quote equates thermal energy with heat? Here's another quote you might find relevant:

 

"Heat may be defined as energy in transit from a high temperature object to a lower temperature object. An object does not possess "heat"; the appropriate term for the microscopic energy in an object is internal energy."

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heat.html#c1

 

I've spent a lot of time on this topic because I'm a scientist and I care about how science is presented to the world.

Incidentally, swansont is in the same position, being a professional physicist who contributes to SFN because he cares about helping other people understand science.

 

I'm disappointed with the tone of this discussion. swansont, whether he's wrong or right, has calmly and civilly explained the physics as he explains it, and you've responded with angry, bolded, all-caps rants. Please try to follow SFN rule 1 from now on.

[spin-1/2-nuclei]

^Yes, if you click on the link, the quote IS the definition of thermal energy, found under the section thermal energy.

 

Cheers

 

A better way to understand why kinetic (translational/random) energy is thermal energy is to ask yourself why a single molecule has no temperature?

 

Temperature is in fact proportional to the average kinetic energy/thermal energy - i.e. - it is a measure/description of the intensity of the average kinetic/thermal energies.

 

However we can say that each individual molecule has a kinetic energy - as I've said before.

 

Hopefully this finally helps..

Cheers

[swansont]

From Wiki:

 

"Therefore, temperature is tied directly to the mean kinetic energy of particles moving relative to the center of mass coordinates for that object."

 

Yes, it's measured in the CoM frame.

 

Heat energy (or just heat) is a form of energy which transfers among particles in a substance (or system) by means of kinetic energy of those particle. In other words, under kinetic theory, the heat is transfered by particles bouncing into each other.

As I said earlier, though, kinetic theory of gases is a subset of thermodynamics. There are other thermodynamic principles that come into play when you get to more complex systems. Radiation being the obvious mode of heat transfer that is missing.

 

No,

 

I'm saying it's right because its right and that YOUR misinterpretation is both

a) resulting from your confusion of the word describe

As well as your now blantantly obvious misunderstanding on translational energy and thermal energy. They are not mutually exclusive - from your own preferred source read: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/rayj.html#c4

 

"The average translational kinetic energy possessed by free particles given by equipartition of energy is sometimes called the thermal energy per particle.

It is also useful for comparisons of other types of energy possessed by a particle to that which it possesses simply as a result of its temperature."

 

Thus my statement "temperature describes - i.e. - measures - the thermal energy which is the heat - i.e. - heat = translational kinetic energy = the energy being transferred IS accurate semantically according to your own preferred source.

 

I'm sorry, but you're just wrong.

Two samples of a substance, but one is twice the amount of the other. They have the same temperature. They do not have the same amount of thermal energy. This is an important point that was missing from the description.

 

An equal amount of two gases are at the same temperature. One of them is an ideal gas. The other is not — it's diatomic. The thermal energy of the ideal gas will be 3/2kT per particle. For the other, it will be 5/2kT. They do not have an equal amount of thermal energy. And neither the thermal energy nor the temperature is heat, which is the point of all this: there is no energy transferred, so there is no heat.

[Tom Booth]

Tom Booth, on 18 August 2011 - 12:52 PM, said:

Well for one thing, the scenario you describe is impossible. In such a situation, the "average kinetic energy" in relation to volume at least could not be the same.

Why is it impossible?

 

I think I already explained that, but whether it is "impossible" or not would depend on what YOU mean by "average kinetic energy".

 

I don't think you can disregard volume.

 

Like, "on average, how many ears of corn are harvested?".

 

This is incomplete and makes no sense.

 

The question should be "on average, how many ears of corn are harvested per acre?"

 

If I have one packet of seed containing 200 corn seeds and I plant 100 in a one acre plot and the other hundred in a 10 acre plot it is virtually "impossible" for the "average yield per acre" to be the same. In one plot the seeds would be much more spread out than in the other. 10 corn stalk per acre vs. 100 stalks per acre.

 

But it is not entirely "impossible" for the "average yield per acre" to come out the same if there were some extraordinary circumstance such as the 10 acres planted with the 10 seeds/acre were provided with much more fertilizer (extra heat from the stove burner in the previous example) than the one acres with 100 seeds/acre.

 

...That is, you are proposing that volume is also a factor (in addition to the kinetic energy) that decides the temperature. (Incidentally, such a proposal is what seems right to me.) Did you actually mean that?

 

Ummm... Yeah, I think so.

 

I'm guessing that is why the equations like PV=NRT and such all have that "V" in there somewhere:

 

---------------------------

The state of an amount of gas is determined by its pressure, volume, and temperature. The modern form of the equation is:

 

PV = NkT

 

where P is the absolute pressure of the gas measured in atmospheres; V is the volume (in this equation the volume is expressed in liters); N is the number of particles in the gas; k is Boltzmann's constant relating temperature and energy; and T is the absolute temperature.

 

http://en.wikipedia.org/wiki/Ideal_gas_law

----------------------------

 

But this is all rather new to me. I just started trying to figure this stuff out myself about a year or so ago so I'm no expert.