I actually agree with Crisp on that statement (or "Me too!") The universe isn't as chaotic as people think, okay you can say there is disorder, but if you record that disorder and play it back it becomes organised. There are alot of theories that argue that there is alot of repetativeness throughout the universe (you could look at DNA coding for an example) if thats the case then that in turn would just prove order.
Stryder, Yes, there are many known self-organizing systems that are far from thermodynamic equilibrium, and tend to decrease entropy. The most well-known is life. Some people are rather ardent that entropy does in fact always increase in a closed system. The earth is, of course, not a closed system -- it receives energy from the Sun. (And yes, even a little bit from all the other stars...) The Sun is an enormous entropy-increasing machine. It has been said that the only reason life is able to decrease entropy locally is because the Sun increases entropy with much greater gusto for the entire Earth-Sun system. Life's just a ripple on the surface. - Warren
"THE QUESTION WAS: How would you give a detailed description of how evaporation due to friction cools the material the once liquid substance had been? This asks for a description at the atomic level." i answered that already, and it is not "my" theory, its my understanding based on what i was taught. i thought i explained this already, but i will again. the friction simply means that the air is interacting with the water, and the individual molecule "borrows" the energy from the "energy bank", meaning the large number of molecules which certainly have enough energy to convert one molecule to a gaseous phase without the whole losing much temperature. then this is repeated billions of times. if you dont understand how evaporation works, then i cant help you. but you say you do understand and have your own theory? lets hear it then because it dosn't seem like you understand basic chemistry.
I personally have no idea what "evaporation due to friction" even means, so I avoided the whole topic like the black plague. - Warren
Chroot: "It [heat] has NOTHING to do with sound waves. " I realize that; I am trying to use that fact against you. Answer me this: IS HEAT VIBRATION of atoms? "Do you understand the difference? " I do. I understand the difference and i was assuming that you would understand too. You do. But you misinterpret what I was trying to say. I am using the fact that you know there is a difference to try and show you something. "Some people are rather ardent that entropy does in fact always increase in a closed system. " I will admit that entropy does always increase in OUR current closed system. But if we had the big crunch happen, wouldn't that be a decrease in entropy in the closed system of our universe? I think entropy only increases because of the state of the universe, not because it is a law of nature. On Radioactive Waves: "and the individual molecule "borrows"" Sure, go ahead and describe things to me as if I were a child. I don't know ANYTHING right? I understand what you are trying to say, but i need one thing answered before I can completely understand it: How does a molecule "borrow" energy from another molecule on the atomic level? This is what I was getting at when I said I needed an explanation on the atomic level.
No. Don't ask me riddles if you want to show me something; you won't get anywhere. So far, you've only shown me that you lack an understanding of physics enjoyed by the average tenth grader. - Warren
"So far, you've only shown me that you lack an understanding of physics enjoyed by the average tenth grader." You have given me no such information. The onlything you have succeded in telling me is that I know almost nothing. Why don't you stick your nose in here and disprove me instead of calling me an idiot? You said: "Temperature is the random motion of atoms or molecules in a substance. " So, you would not consider "random" motion to be vibration? I'm not saying it is going to be "ordered" motion, such as that of a sound wave, but according to your definition of temperature, the random vibration of particles is what you are describing. When the motion of an atom comes in contact with the motion of another atom, you have what we laymen call "bouncing". This is where an atom "bounces" off of another. When you have trillions of these atoms "bouncing" off of eachother, it should create vibration of an atom that bounces back and forth on other atoms.
"Vibration" describes an oscillatory motion, caused by a particle repeatedly exchanging potential and kinetic energies in some form of potential well. For example, individual atoms in a solid may vibrate in the potential well of the bonds formed between it and other atoms. In solid or gaseous phases, there are no such potential wells outside each molecule, so there is no vibration. The particles (either individual atoms or molecules, of course) of a gas or liquid move in random walks, the characteristic scattering length determined by a number of factors, such as the density, the average velocity (also known as temperature), and the interaction cross-section. It is important not to consider the behavior of one individual particle, but instead the statistical implication of many particles behaving as such. The particles in a gas or liquid do not "vibrate," they simply move around with an average kinetic energy of (3/2)*kT, scattering randomly off other particles. "Heat" is transferred from one side of a room to another by trillions of such collisions. Momentum is conserved in inelastic (non-deforming) collisions. When a "hot" particle, one with large kinetic energy characteristic of the hot part of the room, collides with a "cold" particle, one with low kinetic energy characteristic of the cold side of room, the momentum of particles is averaged out. If you consider the integration of any such collision at all possible angles, these collisions serve to drive the entire collection of particles to an average kinetic energy characteristic of the new equilibrium temperature. There is no such thing as "vibration" in the system. There is no correspondence between pressure waves of sound and the average kinetic energy of particles in the medium. If you are unable to perform the statistical calculation of the properties of such a gas, I suggest you take one of two possible paths: 1) Believe it on faith, because people more intelligent than you determined it to be true. 2) Go purchase a thermodynamics book which deals with the behavior of particles in the gas phase. Learn how the equations like average(KE) = (3/2)*kT are derived from first principles. Convince yourself, in the end, that the view I've given you is correct. - Warren
"Believe it on faith, because people more intelligent than you determined it to be true. " Why do you insist on insulting me again and again? In every one of your posts you have at least one, if not more, instulting comment. It was a simple question so that I could see how you thought the mind experiment out. But instead you take it as if I am ignorant. I know that corkboard doesn't stop heat... I give up, obviously you don't want to discuss anything, you just think im stupid. And I don't care, either way works. The only thing I have left is the evaporation example. You didn't know what evaporation by friction was so: Evaporation by friction is when air blows on something like water, and the water evaporates. Someone explained that when the water evaporates it "borrows" heat from its neighbor moloecules and this is how it makes it colder. How would you, chroot, explain how an atom or molecule can "borrow" heat on the atomic level?
There is no such thing as evaporation "by friction." The air blowing over the liquid-gas interface has little to do with the microscopic process of evaporation. When a quantity of liquid is placed in a vacuum, some of the liquid vaporizes and appears above the liquid in the gas phase. The absolute pressure of this gas, at equilibrium, is known as the substance's vapor pressure. An individual particle leaves the liquid to become a gas particle when it has enough kinetic energy, near enough the surface, to escape. This is how evaporation, under all circumstances, ocurrs - particles with sufficient kinetic energy are able to escape from the surface. Particles of a wide continuum of energies are present in the liquid. On average, the kinetic energy of the particles is (3/2)*kT. A liquid in a vacuum chamber reaches an equilibrium, in which the number of particles leaving the liquid surface per unit time is exactly balanced by the number of particles re-encountering the liquid surface and becoming part of the liquid again. The liquid thus does not "evaporate away," though evaporation, and condensation, are an on-going process. When you blow a stream of gas over the surface of a liquid, you're doing nothing microscopically to the liquid particles, unless there are interactions between the particles in the liquid and the particles you're blowing across it. In the case of air being blown over water, there are no such interactions. Based solely on the temperature, some of the particles in the liquid escape the surface. When air is being blown over the interface, however, you prevent the system from reaching an equilibrium. The particles that have escaped the liquid into the gas are blown away, never to re-enter the liquid phase, as they would in a sealed chamber. You're driving the system away from equilibrium by constantly blowing away the particles that leave the liquid surface. Consquently, a puddle of liquid will disappaear faster when you blow air across it -- but NOT because of anything resembling "friction." - Warren
Alright thats fair enough. To tell the truth, I have never heard that explanation before. So would this mean that evaporation due to wind would not happen over the ocean? Could you tell me why this explanation is impossible? : The air actually hits the water particles, making on average some faster and some slower. The faster ones evaporate off, and the slower ones are now colder. Why doesn't that work? Don't just tell me "thats the way it is", see if you can actually disprove it.
Frencheezy, You don't disprove a theory by making thought argument against it; instead, your theory must make definite predictions, which can then be tested via experiment. Particles of the gas do indeed penetrate the liquid; this is how gases become dissolved in a liquid simply by their being in contact. Certainly, some particles of the liquid are ejected (evaporate) by gaining momentum in such collisions. However, the effect is essentially negligible in a large-scale system, since collisions between particles of the liquid occur far more frequently than do collisions between particles of the liquid and the gas above it. I believe you are attempting to explain all evaporative process by collisions between liquid particles and the gas above it. There are several things wrong with this picture: 1) As has been said, if you put a sample of liquid in an evacuated chamber, some of the liquid particles escape on their own accord and accumulate to form a vapor above the liquid. Thus, evaporation occurs even when there is no gas above the liquid. 2) One of the predictions your theory makes is as follows: since molecules of the gas penetrate the liquid, collide with atoms of the liquid, and ocassionally give liquid particles enough momentum to escape the liquid, the vapor pressure of a liquid (which depends upon the average momentum of particles in the liquid) should depend heavily upon the pressure of the gas. In other words, if you increase the pressure of the overlying gas, you increase the number of collisions between gas and liquid particles, thus increasing the number that have the energy to escape the liquid. If you increase the pressure of the overlying gas, your theory would predict that the vapor pressure would increase, as well. This is not true. - Warren
Ya, I guess "your" way makes a bit more sense. Does this mean that evaporation due to wind does not happen over the ocean? "As has been said, if you put a sample of liquid in an evacuated chamber, some of the liquid particles escape on their own accord and accumulate to form a vapor above the liquid. " If one were to create an experiment, having a vacuum chamber on one side, and a wind chamber on the other, would not be a very good experiment. There is more than one variable. The pressure, the composition of the substance above the void (air:nothing), and wind vs no wind. To actaully determine the effects of wind on water, you would have to have a windless air chamber on one side, and a windfull air chamber on the other. The reason for water to vaporize in a vacuum is much different from the reason wind makes water evaporate. In a vacuum the air would spread out across the chamber as much as gravity and H bonds would let them. "Thus, evaporation occurs even when there is no gas above the liquid" I did not say evaporation could not occur by alternate methods... "If you increase the pressure of the overlying gas, your theory would predict that the vapor pressure would increase, as well. " mm, well, i'd need to think about that. I was thinking that the number of collisions is not what makes it happen, but the force of the wind. One more thing: you mentioned the vapor pressure and equalibrium of a liquid. Water has a layer of particles above it that are constantly condensing to water and then revaporizing to a gas. Why doesn't this vapor just fly off? Well I think it is because the particle of water doesn't quite have as much energy as would let it rise above the not-quite-more-dense air. This would mean that even if the wind swept the low water vapor up, the dense vapor would just settle back down. Of course in a place like your arm, the water vapor could be swept off by wind and land on the ground... So that works
i beleive that the main is source of evaporation is the sun, and more so arn't winds genersted by the rotation of the earth and also evaporation(mostly from the sun) , correct? the wind blowing on the surface would increase the number of interactions between the gas and liquid.
This would not be a difficult experiment to build. Go for it. No, it's the same mechanism. I thought my arguments with vapor pressure clearly illucidated that. Are you even capable of describing to me what the particles in "wind" are doing? Let's say we have a 5 km/hr wind blowing, at a temperature of 300K. Can you tell me, microscopically, what's going on in the flow? So wait -- you propose one crackpot theory, and I squash it with reality. Two paragraphs later, you've concocted yet another crackpot theory in its place. Is this some kind of whack-a-mole game? You do understand you'll have to provide evidence of your "not-quite-more-dense air." Sometimes you seem to be asking for help in understand the qualitative nature of things -- and I will gladly help you understand things. Other times you seem hell-bent on assuring yourself that you alone understand things, and everyone else is wrong. Please, give it up. - Warren
chroot: so is the increased evaporation similar to how an airplain flies? there is more movement of air, which results in less pressure on the top of the liquid essentially increasing relative strength of the vapor pressure?
okay warren, since you are so smart then you tell me what is the phenomena responsible for increased evaporation with added air movement?
