# Tag Info

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I could be wrong, but my guess would be it is caused by a change in temperature. At a very simple approximation, the air in the top portion of the jar can be modeled using the ideal gas law: $$PV=NkT$$ or $PV=nRT$ if you're a chemist. By simple inspection, you can see that if the amount of jam stays constant, and the glass doesn't budge, a drop in the ...

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Here is a link to a study comparing heating water in a microwave to heating water in a conventional oven. Depending on the power of the microwave, the volume of the water, and time it's placed inside, the temperature will vary approximately linearly with time until either the system reaches equilibrium (for low power microwaves and large volumes of water) or ...

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If a cold metal object is standing still, and then if we move it, all of its particles gain some energy, kinetic to be precise. All of the molecules gain this energy. But, there is no increase in temperature. Why? Because we connect temperature with the chaotic motion on a molecular level, on the atomic level. This motion of a solid object is on a ...

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You are probably most interested in one of the following: Flash point: lowest temperature at which a material will ignite in a normal atmosphere with an external source of ignition. Autoignition temperature: lowest temperature at which a material will spontaneously ignite in a normal atmosphere without an external source of ignition. For example: if a ...

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How can I calculate the gas pressure given particles per cubic centimeter, and its temperature in Kelvin? as pointed out in comment by KyleKanos $PV=Nk_BT$ where $P$ is pressure, $V$ is volume (in $m^3$), $N$ is the number of particles, $k_B$ is Botzmann's constant and $T$ is temperature in Kelvin. If you rearrange it $P= {N \over V}~k_BT$ so ...

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$Q$ is not the internal energy, but the heat exchanged (absorbed or given away). We use it when we put something near something at a different temperature: the heat exchanged is $Q$. Instead,the internal energy is called $U$, and if we heat something up, then the $\Delta U$ is positive.

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Indeed spherical harmonics are inappropriate, since they are not orthogonal on the restricted domain. This is particularly noticeable in small-scale surveys like ACT and BOOMERanG, but even "full-sky" surveys mask bad data. COBE for instance masked out the entire galactic plane, so the problem has been known since then. The solution presented by Górsky ...

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The units are probably in degrees Celsius. Whenever you add physical quantities together, they must have the same units. You can't add meters to kilograms (although you can multiply them or divide them). The result of such a thing would be nonsensical. However, you can add meters to meters. In your case, you are multiplying degrees by 2. If '2' is ...

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255 values sounds like the value that can be contained in a single byte. The person who created this "code" wanted to be able to represent "reasonable" temperatures with a single byte - they decided they wanted resolution better than 1°C, and they wanted to go down to "about as cold as you can get". This means that the conversion is as follows: From "C" ...

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The problem with the Boltzmann definition is, as you have neatly shown, that its usefulness depends on the assumption that your system is in equilibrium with its surroundings. Without first assuming equilibrium and subsequently setting the temperatures as equal, one cannot show that the Boltzmann entropy satisfies the First Law and hence meaningfully define ...

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I would love to hear an authoritative and concrete answer, but till then, here's what I think: The finite temperature (Matsubara) state is a mixed state (as one should expect, for thermal states). When one Wick rotates and compactifies the time direction into a circle (while imposing suitable BCs), I think one turns the sum in the partition function into a ...

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Most of the time (e.g. at room temperature), the temperature of the lattice $T_\ell$ is equal to the electronic temperature $T_e$. The simpliest argument to give in favor of this is that electrons are strongly coupled to phonons via the so-called electron/phonon coupling. In that way, the thermal equilibrium of the lattice is directly linked the thermal ...

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The relationship of temperature between a planet and a star based on a radiative energy balance is given by the following equation (from Wikipedia): $T_p = temperature\ of\ the\ planet$ $T_s = temperature\ of\ the\ star$ $R_s = radius\ of\ the\ star$ $\alpha = albedo\ of\ the\ planet$ $\epsilon = average\ emissivity\ of\ the\ planet$ $D = distance\ ... 1 In Zero-Energy Model, negative energy associated with Gravity counterbalances positive energy associated with matter, photons, etc. So, No, Big Bang wasn't cold. You are just looking at partial picture (you just ignored Gravity). This is what Zero-Energy Model says: With traditional Big Bang model (which doesn't contain Inflation), the universe started out ... 1 In the standard homogeneous cosmological models the total energy in an expanding volume is zero. This is true for positive, negative or zero curvature and it must take into account the gravitational energy (which is negative), dark energy, matter and heat. Since the gravitational energy is negative the heat can be positive and increasing as you go back ... 1 The definition of the thermal coefficient of resistance (TCR) is the change in resistance per change in temperature divided by the resistance at a specified, fixed reference temperature: $$\mathrm{TCR} = \frac{1}{R(T_\mathrm{ref})} \frac{\mathrm{d}R}{\mathrm{d}T}.$$ Note that$R(T_\mathrm{ref})\$ is a fixed value. It is the resistance given at a single ...

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