First Law of Thermodynamics

[Maggot]

The first law of thermodynamics was expressed in two ways by Clausius. One way referred to cyclic processes and the inputs and outputs of the system, but did not refer to increments in the internal state of the system. The other way referred to any incremental change in the internal state of the system, and did not expect the process to be cyclic. A cyclic process is one which can be repeated indefinitely often and still eventually leave the system in its original state.

In each repetition of a cyclic process, the work done by the system is proportional to the heat consumed by the system. In a cyclic process in which the system does work on its surroundings, it is necessary that some heat be taken in by the system and some be put out, and the difference is the heat consumed by the system in the process. The constant of proportionality is universal and independent of the system and was measured by Joule in 1845 and 1847.

In any incremental process, the change in the internal energy is considered due to a combination of heat added to the system and work done by the system. Taking dU as an infinitesimal (differential) change in internal energy, one writes........copied from wikipedia.

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I dont have the math background to go into the details of this but as far as I can determine, if we substituted "motion" for "work", (in the sense that to move entails a certain amount of work and vice versa), then we could conclude....motion=heat.

An oversimplification,I know but essentially true, No? If this is incorrect or misleading Id appreciate it if youo math and physics guys would please correct and enlighten me. Ill explain why later.

 

[The Mechanic]

Re: First Law of Thermodynamics

I am not a science grad so flame away. But "A body that is in motion stays in motion" so it would seem to me that if something was already in motion it would not be working and in fact decaying in energy as it slows. Also if two objects collide transferring energy there would be no heat transfered only its energy in the form of motion.
However I have always thought that head is energy just in the form of faster moving particles in an atom. But hey I was a college dropout so what do I know.

 

[Donut]

Re: First Law of Thermodynamics

Heat = energy.

I kinda remember the First Law stating that neither energy nor matter could be created or destroyed.

And I also kinda remember that heat was simply energy exciting electrons, causing them to move faster and the friction between them created the heat (and sometimes light - like a glowing-hot piece of steel).

Motion is usually an exothermic process (again, if I remember right) so it could be said that motion generates heat.

Motion = work
Work requires energy, but is not energy, so:

Motion =/= heat
Motion is the application of energy.

There's my nonsensical rambling. I'm going to finish my coffee now.

 

[Wolvenhaven]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: The Mechanic</div><div class="ubbcode-body">I am not a science grad so flame away. But "A body that is in motion stays in motion" so it would seem to me that if something was already in motion it would not be working and in fact decaying in energy as it slows. Also if two objects collide transferring energy there would be no heat transfered only its energy in the form of motion.
However I have always thought that head is energy just in the form of faster moving particles in an atom. But hey I was a college dropout so what do I know. </div></div>

There is heat due to compression and expansion of the objects as they collide, you can't get a perfect 100% energy transfer between the two, and if you collide something fast enough it will more or less turn completely into heat.

Also, heat death of the universe. As energy is transformed into heat, the universe is also expanding, and when you expand in a vacuum, it causes cooling(less energy per volume of space) so eventually there won't be enough energy(heat) in the universe and it will go dark and cold and everything will die.

(Yes I know it's over-simplified but short of getting into a discussion about plasma and such it can't really be explained easier)

 

[WhiskeyWebber]

Re: First Law of Thermodynamics

Degree in Nuclear Engineering... but it was 15 yrs ago... I'll give it a try

I always thought of the 1st law as: conservation of energy in an efficient system; energy can change forms from work, to heat, and back again. In a completely efficient system, both sides of the equation need to balance at all times. This is usually practically used in situations where you have hot gas moving something... like a hot/air/gas mixture in a combustion chamber moving a bullet. I think you could say motion is caused by heat... where there is motion there was heat or if there is heat you will find the *potential* for motion but heat is a different form of energy than motion(work). Again, all of these systems are assumed closed and efficient.

Work = Motion = Force x Distance
Heat is just Heat except for the Miami Heat and they are on vacation without a trophy

 

[The Mechanic]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WhiskeyWebber</div><div class="ubbcode-body">Degree in Nuclear Engineering... but it was 15 yrs ago... I'll give it a try

I always thought of the 1st law as: conservation of energy in an efficient system; energy can change forms from work, to heat, and back again. In a completely efficient system, both sides of the equation need to balance at all times. This is usually practically used in situations where you have hot gas moving something... like a hot/air/gas mixture in a combustion chamber moving a bullet. I think you could say motion is caused by heat... where there is motion there was heat or if there is heat you will find the *potential* for motion but heat is a different form of energy than motion(work). Again, all of these systems are assumed closed and efficient.

Work = Motion = Force x Distance
Heat is just Heat except for the Miami Heat and they are on vacation without a trophy</div></div>
That is kinda' what I was thinking. I was also thinking that you can apply heat to an object and it won't "move". But as Wolvenhaven said, motion can be heat in that it can transfer heat as energy at enough velocity.

Ok something else came to me. Electrons moving faster due to the addition of heat, are they moving faster if the atom is motionless? Would the atoms combined into a molecule of matter cancel each other out if they are bonded yet have the electron opposite each other canceling out centrifugal force or the electron? I don't know just curious now.

 

[Sean the Nailer]

Re: First Law of Thermodynamics

I may be going way off tangent, but I'll just throw in here Bernouli's theorem as well.

<span style="text-decoration: underline">p1v1</span>=<span style="text-decoration: underline">p2v2</span>
t1d1 t2d2

I did the best that I could. I don't know to which direction that you're going to apply this discussion, be it solid/fluid/gas, but there are many forms of work as well as generators/absorbers of heat.

Heat being tantamount to work. Either in addition of, or the removal of, it. Circular, I realize, but as stated it depends on which direction that you want to go. You release gas that has been under pressure, and it get's fantastically cold. You pound on a rivet to hold a number of layers together, and it gets hot. Molecular excitement in one direction or another.

Or, I've missed the cue.

And also there's gravity. As you increase the velocity of a fluid, it's gravity decreases. Hence, airplanes fly.

here's a link that does a better job of explaining.

 

[Maggot]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: The Mechanic</div><div class="ubbcode-body">I am not a science grad so flame away. But "A body that is in motion stays in motion" </div></div>

I believe that "Laws of motion" rather than thermodynamics, but thanks<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Wolvenhaven</div><div class="ubbcode-body">



Also, heat death of the universe. As energy is transformed into heat, the universe is also expanding, and when you expand in a vacuum, it causes cooling(less energy per volume of space) so eventually there won't be enough energy(heat) in the universe and it will go dark and cold and everything will die.

(Yes I know it's over-simplified but short of getting into a discussion about plasma and such it can't really be explained easier)</div></div>

Had never considered that but it makes perfect logical sense.Thanks<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: The Mechanic</div><div class="ubbcode-body">

That is kinda' what I was thinking. I was also thinking that you can apply heat to an object and it won't "move".
</div></div>

But the heat will affect the speed of the movement of the atoms comprising the object, so technically it is "moving", if not from its place. Or if you apply heat to an icecube it will melt which is movement of a sort.

So I think Im on the right track....essentially, movement causes friction which MUST create heat. Think Ill wait a bit for a few more replies, hopefully, before revealing my "master theory". Thanks for the input so far.

 

[The Mechanic]

Re: First Law of Thermodynamics

Movement in a vacuum? That would not create friction would it? What about an object in a vacuum that is neither increasing or decreasing in speed? Like I said college drop out, had to two jobs and a family biz starting so college became fourth place loser.

 

[Sean the Nailer]

Re: First Law of Thermodynamics

movement in a vacuum? No, that would not create friction. Though it would require heat (from the form of work to impel or impact inertia) to create movement. Otherwise, vacant unguided drifting with only gravitational influences on direction.

 

[WhiskeyWebber]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: The Mechanic</div><div class="ubbcode-body">
That is kinda' what I was thinking. I was also thinking that you can apply heat to an object and it won't "move". But as Wolvenhaven said, motion can be heat in that it can transfer heat as energy at enough velocity.

Ok something else came to me. Electrons moving faster due to the addition of heat, are they moving faster if the atom is motionless? Would the atoms combined into a molecule of matter cancel each other out if they are bonded yet have the electron opposite each other canceling out centrifugal force or the electron? I don't know just curious now.
</div></div>
W=Force x Distance so when you have zero distance you have zero work

On your second paragraph, you're combining material science, chemistry, and nuclear theory...kinda cool. The short answer is they all vibrate faster with the addition of heat. The phase change (solid to liquid to gas) is what's usually required to extract work. A hot solid is vibrating more and has more inherent energy but it is not as useable as a hot gas would be. The assumption is that all particles are increased in their speed of vibration proportional to one another to a point. So yes, the electrons aka "those little fuckers" are moving faster but so are the rest of the nuclei. If you hook a potential across a solid, at some point you have imparted so much energy to the little fuckers that you actually get them to jump up in energy levels... sometimes they become unbalanced and throw off light to jump down a level to reach a steady state... This is what is referred to as a quantum shift.

 

[Fred_C_Dobbs]

Re: First Law of Thermodynamics

Thermodynamics defined in 20 (layman's) words or less:


1. You can't win.

2. You can't break even.

3. You can't get out of the game.

 

[WhiskeyWebber]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sean the Nailer</div><div class="ubbcode-body">
And also there's gravity. As you increase the velocity of a fluid, it's gravity decreases. Hence, airplanes fly.
</div></div>

As the velocity of a liquid increases there is a resultant pressure drop. The difference in speed of air below and above the wing creates a pressure gradient situation which "sucks" aka "lift" the wing into the air. They should have called it suck instead of lift and then everyone would know why airplanes fly... because wings suck. Gravity is a constant bitch and she will never be decreased... she wants your ass on the ground.

 

[The Mechanic]

Re: First Law of Thermodynamics

Neat stuff. Even at 47 I am learning new stuff every day.

 

[WhiskeyWebber]

Re: First Law of Thermodynamics

btw the absence of heat - 0 Kelvin is an interesting subject too... that's the temperature at which all movement ceases at the molecular level.

not sure what this has to do with shooting though

 

[Handloader]

Re: First Law of Thermodynamics

It all goes back to the basic equation of F(force)=M(mass)*A(acceleration), just substitute were needed and run the equation. And as A is the first derivative of velocity, velocity must be changing to impact the equation (either positive or negative...I guess it would depend on your relative plane).

Point is, "motion" plays a critical role in the overall definition of "energy," i.e. Einstien defined energy as E=MC^2, where some mass * a constant until the speed of light is reached. That said, motion DOES NOT equal heat, it is but a small part of the entire equation.

These are my thoughts in this, but it has been 11 years since I finished my calculus base physics classes......

 

[WhiskeyWebber]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Handloader</div><div class="ubbcode-body">

Point is, "motion" plays a critical role in the overall definition of "energy," i.e. Einstien defined energy as E=MC^2, where some mass * a constant until the speed of light is reached.
</div></div>
C= the constant for the speed of light
One of the things Einstein was saying with E=MC^2 is that mass can become pure energy. In the original nuclear weapon, one dime's worth of mass was converted to energy. It doesn't take much mass to produce an unbelievable amount of energy... that's why people are chasing cold(controlled) fusion.

The other cool thing about E=MC^2 is that it says that as things approach the speed of light it gets heavier and heavier in an exponential manner thus requiring more and more force to accelerate them. So anything that has mass can never travel at the speed of light... it has to be transformed into pure light energy to do that. Also, time dilates and length contracts as you approach the speed of light so if you're tired of bumping your 28" barrel on the door on the way into the house and your wife is always mad at you for being late; you could speed up to near the speed of Light and your barrel would fit nicely and your watch would always say you were on time

 

[The Mechanic]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WhiskeyWebber</div><div class="ubbcode-body">btw the absence of heat - 0 Kelvin is an interesting subject too... that's the temperature at which all movement ceases at the molecular level.

not sure what this has to do with shooting though

</div></div>

Ohh ohh ohh, OK so I have two spheres of solid gold .54 caliber musket balls that are at 0 Kelvin in a vacuum hurtling at each other at 100 miles and hour and they hit each other. Did they actually do any work?
If a tree falls in th.... never mind.

 

[WhiskeyWebber]

Re: First Law of Thermodynamics

If it was truly a zero K system nothing would be moving... not even Lebron's PR team trying to explain his epic faliure in the finals... seriously, a zombie Len Bias would have done a better job in the fourth quarter of all of those games.

 

[Fred_C_Dobbs]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WhiskeyWebber</div><div class="ubbcode-body">...The difference in speed of air below and above the wing creates a pressure gradient situation which "sucks" aka "lift" the wing into the air. They should have called it suck instead of lift and then everyone would know why airplanes fly... because wings suck....</div></div>
NASA sez: Bernoulli was right but that's not <span style="font-style: italic">really</span> what makes airplanes fly

 

[Sean the Nailer]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WhiskeyWebber</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sean the Nailer</div><div class="ubbcode-body">
And also there's gravity. As you increase the velocity of a fluid, it's gravity decreases. Hence, airplanes fly.
</div></div>

As the velocity of a liquid increases there is a resultant pressure drop. The difference in speed of air below and above the wing creates a pressure gradient situation which "sucks" aka "lift" the wing into the air. They should have called it suck instead of lift and then everyone would know why airplanes fly... because wings suck. Gravity is a constant bitch and she will never be decreased... she wants your ass on the ground. </div></div>

Considering the discussion at the time had to do with motion and heat, I added in there Bernouli's theorem because it could be pertinent. Depends on the tangent of the OP.

And, in your analogy the wing itself does not create "suck", it is the motion of the wing through the fluid (air) that creates "a" suck.

Lastly, I did NOT say that "gravity" shall be decreased,,,, while I did say that "IT's" gravity shall be decreased.

I could have said weight, but the weight of the actual object doesn't change. I could have said mass, but again, the mass of the object doesn't change. What is referred to here is, the object in motion which is aerodynamically being lifted through the fluid due to differing turbulence and flow rate. This would then be creating a vacuum, and (if you will) instilling a "counter-gravity" force upon the object.

And at the same time, that 'vacuum' area will also be of a lower temperature.

Or something like that.

This is of the exact same principle that allows the average ship to turn left or right (Port or Starboard) in the water using it's rudder. That being "horizontally changed" and and airplane's flight being "vertically changed".

 

[WhiskeyWebber]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fred_C_Dobbs</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WhiskeyWebber</div><div class="ubbcode-body">...The difference in speed of air below and above the wing creates a pressure gradient situation which "sucks" aka "lift" the wing into the air. They should have called it suck instead of lift and then everyone would know why airplanes fly... because wings suck....</div></div>
NASA sez: Bernoulli was right but that's not <span style="font-style: italic">really</span> what makes airplanes fly </div></div>

Interesting, when flying upside down with an asymmetrical wing I have to put in lots and lots of forward stick to counteract the less efficient upside down wing. The only time I felt I could "feel" the opposite action/reaction force is in the equation is only during ground effect or flying an asymmetrical wing upside down.

 

[WhiskeyWebber]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sean the Nailer</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WhiskeyWebber</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sean the Nailer</div><div class="ubbcode-body">
And also there's gravity. As you increase the velocity of a fluid, it's gravity decreases. Hence, airplanes fly.
</div></div>

As the velocity of a liquid increases there is a resultant pressure drop. The difference in speed of air below and above the wing creates a pressure gradient situation which "sucks" aka "lift" the wing into the air. They should have called it suck instead of lift and then everyone would know why airplanes fly... because wings suck. Gravity is a constant bitch and she will never be decreased... she wants your ass on the ground. </div></div>

Considering the discussion at the time had to do with motion and heat, I added in there Bernouli's theorem because it could be pertinent. Depends on the tangent of the OP.

And, in your analogy the wing itself does not create "suck", it is the motion of the wing through the fluid (air) that creates "a" suck.

Lastly, I did NOT say that "gravity" shall be decreased,,,, while I did say that "IT's" gravity shall be decreased.

I could have said weight, but the weight of the actual object doesn't change. I could have said mass, but again, the mass of the object doesn't change. What is referred to here is, the object in motion which is aerodynamically being lifted through the fluid due to differing turbulence and flow rate. This would then be creating a vacuum, and (if you will) instilling a "counter-gravity" force upon the object.

And at the same time, that 'vacuum' area will also be of a lower temperature.

Or something like that.

This is of the exact same principle that allows the average ship to turn left or right (Port or Starboard) in the water using it's rudder. That being "horizontally changed" and and airplane's flight being "vertically changed". </div></div>

Sean- I just realized you're from Canada... maybe we have some terms that were lost in translation. It wouldn't be the first time for me... I used to get into debates with Engineers in Edmonton and after a while I'd realize we were saying the same thing only with words that had different and sometimes opposite meanings. Pictures are so much easier than words

 

[Sean the Nailer]

Re: First Law of Thermodynamics

All's good; we're cool; and the first round's on Goldie.

After all, He started this. HA!!!
(maybe the second, too)

 

[ArcticLight]

Re: First Law of Thermodynamics

Energy is neither created nor destroyed, only transformed.

Friction=heat=energy.

Move electrons fast enough and they generate heat.

heat them and they move fast enough.

That's all I know!

 

[Maggot]

Re: First Law of Thermodynamics

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sean the Nailer</div><div class="ubbcode-body">All's good; we're cool; and the first round's on Goldie.

After all, He started this. HA!!!
(maybe the second, too)</div></div>

Im buyin. Whats yur poison?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ArcticLight</div><div class="ubbcode-body">Energy is neither created nor destroyed, only transformed.

Friction=heat=energy.

Move electrons fast enough and they generate heat.

heat them and they move fast enough.

That's all I know!</div></div>

Thats basically what I was going for.

Thanks for all the replies.

 

[Greg Langelius *]

Re: First Law of Thermodynamics

Motion is displacement in time and space. All objects are in motion relative to some common point in space-time.

Motion is not work. Work is what's necessary to alter the direction or speed of a mass.

Newton's laws note that an object/mass tends to remain at rest or in motion until acted upon by an additional force, at which time work is expended. Until the additional force is applied, no work occurs.

Work is the application of force to mass over a span of time.

A moving or stationary object (say..., a hanging mass) possesses potential energy. Work alters the magnitude of that potential energy

Greg

 

[oldgrayone]

Re: First Law of Thermodynamics

In a ideal world work in would equal work out which would allow true papetchual motion.

I a real world work in will not equal work out due to losses such as friction. This is calculated in BTU's and the nasty little thief is know as Entropy.

Entropy- A thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system

 

[WhiskeyWebber]

Re: First Law of Thermodynamics

Entropy is proof that God exists but I'm seriously going to need a beer to explain that one