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It is mostly because different liquids have different Thermal conductivity and Heat capacity. http://en.wikipedia.org/wiki/Heat_capacity http://en.wikipedia.org/wiki/Thermal_conductivity Of course viscosity of Liquid is effective but it is a secondary factor.

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For the limit of an infinite number of intermediate baths, we can make the approximation that $T_\mathrm{bath} = T_\mathrm{block}$, so for the bath: $\delta S_\mathrm{bath} = \frac{\delta Q}{T_\mathrm{block}} = -\frac{C\delta T_\mathrm{block}}{T_\mathrm{block}}$ or $d S_\mathrm{bath} = -\frac{C}{T_\mathrm{block}} d T_\mathrm{block}$ Note that $\sum_{i= ... 3 An electric heater that has "mechanical inefficiencies" as Programmer mentioned will nonetheless ultimately lead to near 100% conversion because things like expansion of wires, creaking sounds etc., will be absorbed by the surroundings and turned into heat, especially in a well-insulated house. I justify leaving the bathroom CFL light on in the winter (it ... 3 Transfer of heat from one source to another can be very efficient. In fact, the first law of thermodynamics says that the internal energy of a system can be transferred as heat of there is no work done through compression, expansion etc. For example, electric heaters can deliver close 99% of the heat energy to their surrounding with minimal loss from ... 12 "Total energy of the Earth" is somewhat of an odd concept, but there's no reason we can't really entertain it. It brings up some genuinely difficult questions. The right way to approach this is to define the system correctly and then identify forms of energy content and flows. Things to "count" in the Earth's energy: Heat content Nuclear energy ... 6 The heat generated from the Earth's core is about 4x10^13 W while the Sun provides about 1.7x10^17W so although the Earth's core is slowly cooling this has very little effect on the Earth's temperature. The Earth is in equilibrium between the energy received from the sun and the energy it emits into space. If the amount received changes, then temperature of ... 2 I'd say depends on the definition of 'total energy' - see Alan's answer above. The total thermal energy is not in equilibrium, it is increasing: global warming, that is an imbalance of around 0.5 W/m^2, corresponding to a total imbalance of 2.5x10^14 watts (if I did the multiplication correctly...) 3 From the article you cited: A fan draws in humid air and carries it through a refrigerated evaporator. Evaporator is just a heat exchanger in which the working fluid (refrigerant, inside the tubes) evaporates. It accomplishes this by sucking out the heat from the air flowing through. This is the rectangular portion on the right side of the apparatus ... 3 Dehumidifiers work by first cooling the air, then heating it back again. The cooler air can hold less moisture, so the cool air dumps much of its moisture load. This separates the incoming moist air into two streams, dry air and liquid water. The heat output of the heat engine that makes the cold temperature is used to warm the cooled air again. Actually ... 0 I'll elaborate on my comment. Maxwell's relations are just observations that second partial derivatives of a function commute. So for some potential$\Phi(x,y)$, if you differentiate,$d\Phi = (\partial_x \Phi) dx + (\partial_y \Phi) dy$, then because second partial derivatives commute, i.e.,$\partial_y \partial_x \Phi = \partial_x \partial_y \Phi$, we ... 4 Let a quantum system with Hilbert space$\mathcal H$and hamiltonian$H$be given. If the system is in equilibrium with a heat bath at temperature$T$, then the system is in a so-called mixed state and is modeled by a linear operator on$\mathcal H$instead of as a vector in$\mathcal H$. This operator is called the density matrix (or density operator). ... -1 I'd measure this. BIOS can say which is the temperature of your CPU, that is what you should check with and without the CPU fans. This is what you should measure, with and without fans, in all possible overclocking scenarios. If you want to handle the problem with more physics, you could from the data points and fit to an experimental formula. 3 If you look at the first law of thermodynamics, $$dU=\delta Q-\delta W=TdS - pdV$$ then consider a reversible processes ($dU=0$), then we get $$TdS=pdV$$ Then using the ideal gas law,$pV=nRT$, we find $$dS \sim \frac{dV}{V}$$ The volume considered would be the volume of the system (e.g., a gas), with its infinitesimal increase(decrease) signified by ... 0 I guess the definition of derivative is still applicable: you take the limit of "modulus at pressure =$\triangle p$minus modulus at pressure = 0" divided by$\triangle p$for$\triangle p\rightarrow 0$. 0 As the hot air goes up and the cold air goes down, the radiator is located where there is a better circulation, ie, even though the window is double glazed, there will always be cold air entering the division by the material itself. So the cold will push the hot air inside the room. Another explanation can be the fact that external walls can have thermal ... 0 I have since found this pdf from CVI Melles Griot giving a temperature coefficient of 0.016 nm/°C at 400 nm, increasing to 0.027 nm/°C at 820 nm. This will vary between coating types but it is enough to get started. 1 With solids atoms are mostly locked in place so it makes sense there can be lots of different crystal structures and atomic packings. For liquids and gases though their defining characteristic is that their atoms are mobile enough to flow and fill a container. You can't both have structure and mobility. 1 I suppose it depends on application. For example, broadband dielectric mirrors sold by ThorLabs do not specify their temperature-dependence for the obvious reason of redshift magnitude you specified. Even narrowband dielectrics and laser line mirrors don't usually specify this. However, other devices such as crystal optics for wavemixing can strongly depend ... 1 Because under window is the place where delta-T (the Change in Temperature) is largest in the whole room. The larger is delta-T, more efficient the system is. Window even when closed is still a coldest place, because it is a thinnest wall. Cold air flows downwards, thus under window. What is an efficiency of a radiator depends on whether your goal is to ... 0 I wouldn't say it is a myth. Like you say, it's complicated. When you are in the sun, the predominant source of heating is from incident radiation, whereas in the shade cooling would take place primarily through convection, conduction and evaporation. When you are in the shade, you are just not that hot compared to your surroundings for radiative cooling to ... -1 Its because the hot air that is created by the radiator heats the colder window making the glass warmer... therefore the glass is allot less likely to condensate and at the same time keeps the room allot warmer because the heat will radiate out wards away from the window along with any drafts or such ... also if the radiator is placed on a wall without a ... 0 While studying the behavior of a gas filled balloon on cooling down, one needs to understand how the gases behave while being cooled. A helium filled balloon immersed in liquid nitrogen would just undergo shrinkage due to contraction of helium gas. On the other hand, a balloon filled with air will behave differently. Air roughly contains 77% nitrogen, 22% ... 0 As mentioned by Programmer, saying that if the wire temperature is constant then half of the heat will flow in either direction is incorrect. It really depends on the boundary conditions on either end of the wire (since it is of finite length). Assuming that the wire is at a spatially uniform temperature (not constant in time) and has same boundary ... 0 Had the wire had a constant temperature T, the half of the power$I^2R/2$will be passing the left end, the other half will be passing the right end. I think this is a wrong statement. This is a common assumption used in a thermo-electric circuit theory to derive the equations. I would argue that this is valid in the case where the properties of the ... 1 The reason why you got electric shock is because the way you kept it in the bucket is improper or device is faulty. You might have noticed that there is an aluminum hook along with the plate extending which marks min and max water level marking. It should be in contact with water. This plate and hook is connected to earth. It ensure water in the bucket is ... 1 Reason is quite simple. If you have a window without radiator and outside is really cold, the window glass would be cold as well. This will lower temperature of the air around the window and this air will flow immediately down (physics). So if someone want well heated room with very cold floor .. do it, put radiator to opposite side. That's why it is wise ... 4 This device looks like a inherently bad idea safety-wise, for the reason you found. I don't know what exactly is inside the handle, but you have to assume all it is doing is connecting wall power to a resistive heating element. I imagine the outside of the heating element is intended to be insulated from everything else. (By the way, this has nothing at ... 0 A number of reason: - the wall under the window is basically useless - placing the heater under the window allows you have a more even temperature throughout the room: the window is the coldest place in the room, if you were to place a heater on the other side of the room and wanted to reach a certain temperature by the window, the other part of the room ... 3 As the hot air goes up and the cold air goes down, the radiator is located where there is a better circulation, i.e. even though the window is double glazed, there will always be cold air entering the division by the material itself. So the cold will push the hot air inside the room. Another explanation can be the fact that external walls can have thermal ... 36 Since this is a physics forum I assume the OP is interested in a quantitative answer in terms of the efficiency of the system and how it differs based on the relative positioning of heat sources and heat sinks. The math required to analyzed such a system is too much for me to manage right now, but I believe the following principles apply and are objectively ... 6 As described in the other answers, putting the radiators (or hot air vents in a forced-air system) under the windows offsets the greater heat loss of the windows, but there is another reason. As room air flows over the surface of a window, it will lose heat to the window (and the outside). This can cause moisture in the air to condense out onto the window. ... 7 As Programmer mentions, by putting the radiator in front of the area most prone to heat loss and ingress of cold air, you are effectively screening off the room from cold air. However, there is also the fact that radiators are often quite a bit hotter than other heat sources such as forced air. Therefore it makes sense to put it in the coldest part of the ... 50 The reason is because the heat loss occurs mostly in the windows and the fenestration. The idea is that you would like the incoming air to be heated up. Also, it creates an air curtain that prevents more heat from being lost through this exposed areas. The final reason is to make the temperature of the room more or less uniform. If the heaters were placed at ... 2 You should be using the coefficient for the metal in the heat sink. The thermal paste is there simply to close a gap between the two surfaces. With a gap you have to worry about extreme inefficiency between the junction of the two surfaces. The thermal paste isn't perfect and there is still some efficiency loss in the interface but you should probably ... 1 My guess would be it's there to prevent the cooling air from accumulating below the window and flowing into the rest of the room. Anything goes to avoid cold feet ;) 47 Partly practical, the wall under the windows isn't useful for anything else. We had a house where the heaters were placed in the middle of the only empty walls, so nowhere you could put furniture, bookcases, etc. Before double glazing there would be a draft from the windows so the idea was to heat this incoming air by having a radiator immediately below the ... 0 See http://arxiv.org/abs/quant-ph/0512105. It gives a derivation of Landauer's Principle from the two postulates of the Second Law of Thermodynamics, and shows how Landauer's Principle follows from the second postulate. 0 if the reaction is not problem, the answer is proper. because nitrous oxide decomposition release energy. then the temperature is high than react with oxygen. In fact the temperature is high than reality. because the reaction is not correct. the reaction production include many other species. 0 I don't know if there is a reasonable technical solution to your problem, but I suspect that, from the point of view of physics, item 4 is manageable in principle: the inside of the bunker does not have to be empty. For example, you can keep a couple of tons of water in the bunker:-) You can also consider boiling latent heat for some liquid, but this can add ... 10 If the metal pan was cool then you would expect to see water droplets staying in the same place once any original movement had dissipated. You would have a combination of cohesive forces within each water droplet and adhesive forces between the water and metal surfaces. With the metal having a temperature well above the boiling point of water, the water ... 1 Think about this is physical rather than algebraic terms for a moment. Notice that the term$\frac{T_L}{T_H}$is the ratio between the highest and lowest temperature. This ratio tells you how well heat can flow from$T_H$to$T_L$. The absolute temperatures don't actually matter, only their ratio. So what is the physical meaning of$T_L = 0$? It means ... 0 Real bodies absorb radiation of given wavelength with intensity proportional to their emissivity$\epsilon(\lambda, T)$, which in general depends on the temperature and possibly also on other state variables. Whether the absorption increases or decreases with temperature depends on the kind of body and range of temperatures, so it cannot be stated generally. ... 2 If you want to combine the two equation the easiest way is probably taking a "pseudo-derivative" of the equation of status:$2kV\Delta V = n R\Delta T$And then substitute$\Delta T$. I don't find the resulting expression for$C_x\$ very illuminating, however the initial hypothesis is pretty weird.

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The rules of Black Body radiation say: no. Assuming the composition of the box doesn't change, its absorptivity is the same regardless of temperature. What does change is the amount of energy it'll radiate, which is a direct function of temperature (black body again). This often confuses folks, as the spectral absorption curve (i.e. percent of photons ...

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I think you have a misunderstanding of the technical terms vapor pressure, boiling and partial pressure. Vapor pressure or better equilibrium vapor pressure is the pressure at which an equilibrium is reached between evaporation and condensation at the liquid surface. Usually it is a function of liquid temperature. E.g. water has a vapor pressure of about ...

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The answer is that a decrease in temperature does decrease the mass, though in most cases that change is exceedingly small. Temperature is a macroscopic phenomenon, so you can't really talk about the temperature of a single string or an atom. However consider the following analogy: If you have an isolated string (or atom) in some excited state, then to ...

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Apparently these interpretations are deduced from equation (1), which doesn't hold in non-extensive systems. So it seems that these potentials are ,inherently, extensive quantities, and have no meaning in non-extensive systems. I do not think that these interpretations depend on (1). They can be derived without (1) or the homogeneous property of ...

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Correct, your equation (1) does not hold in non-extensive systems. Also, none of the equations hold for a galaxy since it's not in equilibrium. Supposing we do have equilibrium, though, equilibrium statistical mechanics is exactly the tool we need to extend these quantities to non-extensive and microscopic systems. This was one of Gibbs' main goals in his ...

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You seem to have overcomplicated this question quite a bit, you don't need to go further than the theory of relativity to find the answer. Heat is simply chaotic movement on the molecular and submolecular level, and as relativity dictate that any object moving relative to an observer will to that observer appear to have greater mass with greater relative ...

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