A science question

CF,Thanks. If you are correct, then I think I finally "got it."Once again, I had a half-way decent concept of WHAT was happening, but had trouble with the terminology (you may recall a similar problem with "random mutations"...heh).Thanks everybody for your patience...
--TheLitAbE:
The illusion was that there was a type of energy called heat energy, eh? Haw!This message has been edited by TheLiteralist, 03-07-2005 14:40 AMThis message has been edited by TheLiteralist, 03-07-2005 14:42 AM

Hey All,I've really enjoyed the in-depth discussion (since I totally misunderstood something I THOUGHT I understood so well).This is the way I'm understanding it so far:

1. There is no such thing as "heat energy"--my biggest problem: inventing an entirely new form of energy!
2. Heat is not NECESSARILY light (but can be)
3. Even though temperature measures kinetic energy and heat can result from kinetic energy, heat is NOT kinetic energy
4. Internal energy is how much molecular kinetic energy a body possesses: a body cannot possess heat, because heat is the flow of energy from a hotter object to a colder object
5. Heat is a term of convenience and very limited in scope of application--technically
6. Heat is a specific type of energy transfer--specifically heat is the flow of energy FROM A HOTTER OBJECT TO A COLDER OBJECT--(I assume this to be net flow--is that correct?). Energy transfers not meeting this criteria are NOT heat.
7. How the energy flows from the one object to the other is irrelevant: if it is energy flowing from a hotter to a colder object, it is heat (but could also rightly be described as light, radiation, conduction, convection, etc.--depending on the particular circumstances)
8. Regarding a single atom or photon: there can be no heat until the atom or photon contact something else because heat is the flow of energy from a hotter object to a colder object. And you would have to have some way to see that the single atom or photon is hotter than the object contacted--is that even possible?

Have I got it?It's been a little humbling, but also kinda fun.Thanks again all,
--TheLitAbE:Oh yeah, temperature is something a body possesses. Temperature is NOT heat...even though we colloquially use temperature to see how "hot" something is. Temperature is really a measure of internal energy, right?This message has been edited by TheLiteralist, 03-07-2005 20:11 AM

This is off-topic, but I hope I will be indulged...In the case of an electrical circuit with a resistor (a light bulb,for instance)...The battery and wires transfer energy to the resistor (the bulb). The battery and light start off at the same temperature (not hotter and colder). And the energy transferer (the battery and wires) do not get as hot as the energy transferee (the bulb). The internal energy (and temperature) of the bulb increase--however the bulb does not now contain heat...it merely has an increased internal energy (its molecules are buzzing about a bit more than before). So in this case we have an energy transfer from one object to another object of similar temperaature. After some time, it becomes a transfer of energy from a colder object to a hotter object (this energy flow is NOT heat). However, if you touch the bulb, by conduction, the bulb--a hotter object--will transfer energy to your hand--a colder object. This energy flow IS heat...and even the layman (me?) will recognize it as such.Have I got it? Or did I stupidly tread into chemistry (one of my worst subjects) and totally mess it up?--TheLit

A stale degree? Ha!Well, Level I Physics a decade ago...that's MY knowledge level on the subject. Just enough to make me dangerous.

Percy, Thanks. I thought I was being pretty faithful to the definition given by hyperphysics...whether it contradicts others or not.I grabbed this from one of Sylas's posts:

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From heat at hyperphysics;

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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.

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It seems to contradict your definition. According to the above definion, heat is energy...energy in transit from a high temperature object to a lower temperature object. I disagree (based on the above definition). Light is energy in transit. If that transiting energy happens to be traveling from a higher temperature object to a lower temperature object...then light, in that case, is heat. If that heat (the light going from the hotter to the colder object) gets absorbed by the colder object then the colder object gets heated as per the above definition. According to the above definition that's exactly what heat is not. According to the above definition, heat is not possessed by an object, but the kinetic energy of its molecules is possessed by an object. Also, the kinetic energy of molecules is not necessarily energy in transit...though it could be. When it is energy in transit it is not necessarily heat...though it could be (if it transits from a hotter object to a colder object). Internal energy is what you are defining as heat--i.e., the kinetic energy of molecules, which, if the definition of heat provided by hyperphysics is correct, then "the kinetic energy of molecules" is NOT heat.Also at hyperphysics:

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Internal energy is defined as the energy associated with the random, disordered motion of molecules. It is separated in scale from the macroscopic ordered energy associated with moving objects; it refers to the invisible microscopic energy on the atomic and molecular scale. For example, a room temperature glass of water sitting on a table has no apparent energy, either potential or kinetic . But on the microscopic scale it is a seething mass of high speed molecules traveling at hundreds of meters per second.

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If the above definition is true, then heat is only energy moving from a hotter object to a colder object...that is limited. IOW, heat is not all energy but only energy in transit--not even all energy in transit...only energy in transit from a hotter to a colder object. That is limited. For instance, if a photon leaves the earth and travels to the sun, because this is energy transiting from a colder object to a hotter object it is not heat. Something can get hotter (experience an increase in temperature) without being heated, too. Because to be heated, heat has to have flowed into the object from a hotter object. That is a limitation concerning heat, too. Eh? It's never been clearer to me...unless hyperphysics's definition is wrong. If there is any fog about me...it is the multitude of opinions of what heat is...thus my hedging, which I presume you take to be my "gray fog of confusion."

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Have I got it?

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I'd say so.

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If you're right, then I haven't got it yet. If Sylas is right, I maybe do. If you AND Sylas are correct, I am confused! Thanks for the compliment. I do hope I've not come across as rude. It's just that now that I feel like I understand heat, I disagree with your definition fundamentally.--TheLit

Sylas, I imagine many people might have a hard time being talked about in third person on a public forum; however, I find it amusing (in this case, at least). I'm glad you did pick up on the (one?) part that was right; I'm even more glad you have taken time to correct the horrible misunderstandings I had about the concept of heat. I took physics in high school and level I physics in college (my major was Accounting, though--I never finished the degree). I also took both Chem I and college level chem (level I chem) in high school. So between two Physics courses (well, the book in both was extrememly similar...its just that in college we covered more of the book in less time...whew!) and two Chemistry courses, heat was discussed in formal terms somewhere along the way (but more than a decade ago--so it was not fresh in my mind).You had earlier added one more restriction on the definition of heat: that the transiting energy from the hotter to the colder object not do work (I have some fuzzy recollection of "work" from physics class)...thanks for the clarification--as I had not considered that further limitation. It is perhaps the most important restriction: I remember in physics frequently seeing the phrase "the energy is lost as heat due to friction."For the benefit of all, I confess to a multitude of horrendous erroneous assertions regarding the definition of heat...both before and after reading the definition from hyperphysics--but particularly before.Heat appears to be a chameleon energy--i.e., it can be any or a combination of any of the other kinds of energy (kinetic, mechanical, light, chemical, etc.) as long as it is energy in transit from a hotter to a colder object and not being used to accomplish work.AbE: Okay, I see heat must be a non-mechanical form of energy, too (info gotten from one of Percy's links, answers.com or something).I'm sure I still have some incorrect concepts regarding heat, but I did want to thank you for taking the time (to the point that you'd look up material in textbooks) to correct the more horrendous errors I made--and even some of the less horrendous (if some were not so horrendous).--TheLitThis message has been edited by TheLiteralist, 03-09-2005 02:59 AMThis message has been edited by TheLiteralist, 03-09-2005 04:26 AM

Sylas, Thank you Sylas. Doesn't this seem to override any need to know the complexities of how energy (maybe using the general term "energy" will avoid the need to discuss heat?) moves about within the earth? This information seems to answer my earlier question in Message 38.However, JonF indicated that my question could not be answered unless we measured escaping energy from the earth system over say 100,000 years (at least) in his Message 75.OTOH, I've got contracycle telling me in Message 67: Is it possible we can make such determiniations about JUPITER but have to wait 100,000 years to figure it out about our own earth?I am not saying JonF is wrong. I am wondering what I am missing, though. Based on your assertion that the earth is experiencing an overall net energy loss of a factor of about 1.00003...it would seem possible to make at least a rough estimate of how long it would take the earth to cool to its present state from a completely molten one.--TheLitThis message has been edited by TheLiteralist, 03-09-2005 03:53 AM

Percy, Temperature is NOT heat nor even a measure of heat. Temperature is a measure of object's internal energy--the energy associated with the movement of an object's molecules. Even though an object can be hot (it's temperature is relatively high); that object cannot be properly said to "have heat," because heat is energy IN TRANSIT. Whatever energy an object POSSESSES is NOT in transit and, therefore, cannot be heat. An object POSSESSES the energy associated with the movement of its molecules (internal energy); therefore, THAT energy is NOT heat--since heat is limited to "energy in transit." I'm not 100% sure, but I think heat can indeed be kinetic energy--I am thinking of conduction. If a cooler object contacts a hotter object, the hotter object's molecules will collide with the molecules of the cooler object. This appears to be kinetic energy in transit from a hotter object to a cooler object, which is heat. However, until a cooler object contacts the hotter object the kinetic energy of the molecules of the hotter object cannot ever be heat.If something's molecules move around more than before, then it is hotter than it was before (it has a greater internal energy, but it doesn't have any heat). The sun has a very high temperature, but it has no heat. The sun radiates a great amount of energy (light), but if there were no cooler objects around for that energy to contact, then the sun would not radiate any heat, either. Not even all energy in transit is heat...it has to be in transit from a hotter to a cooler object in order to qualify as heat.Earlier in the thread, I incorrectly limited heat to IR, and now you are trying to redefine the term entirely by giving it the exact same definition that "internal energy" has. Why? It makes no sense to me. Heat is energy in transit. Internal energy is not in transit and, therefore, is not heat--even though it is what causes the phenomena we call temperature. Why do you keep insisting that light is not heat? Some light IS heat. Heat is energy in transit from a hotter object to a cooler object. Light is energy in transit. If that light is going from a hotter object to a cooler object, then that light is energy in transit from a hotter object to a cooler object and, therefore, heat. This is a good concern. I've seen people act like they understand something when they don't (I've done it myself). However, I think I've got a fair grip on the basics of the concepts...I am worried about you, though...When molecules are heated they move around more (but do not gain "heat"). Also, energy can be added to an object in other ways than by heat to make the molecules move around more without being heated (to be heated an object must specifically have received energy from a hotter object). I'm not sure, but I think that an exothermic chemical reaction will increase the internal energy of the chemicals involved (and, therefore, their temperature)...but this is not heating (even though the chemicals got hotter). However, the increased kinetic energy of the chemicals will increase the kinetic energy of the molecules of the glass of the beaker (by conduction)...this is heating.This message has been edited by TheLiteralist, 03-09-2005 11:08 AM

Percy,Instead of avoiding the term heat...how about I relent (since there's more I don't know than know about the subject); I will know what you mean when you say something has heat--that's the way I've said it all my life anyway. All my "precision" was quite unjustified (but it was a little fun). I'm glad that many of my misconceptions were corrected, though (thanks all).We now return you to your regularly scheduled thread...and simpler times! --TheLit