It's the physical property that indicates the degree/intensity of heat present in a substance or an object. It can be expressed and measured according to various scales.

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Temperature in the Hamiltonian limit

There is a well known connection between statistical mechanics in D spatial dimensions and quantum field theory in D-1 spatial dimensions. Changing the temperature in statistical mechanics corresponds ...
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How much water did I actually drink? [on hold]

Water expands at temperatures over $5^\circ\mathrm C$ strictly monotonic. If you now drink $1~\mathrm{L}$ water ($5^\circ\mathrm C$) which will expand in your body on $37^\circ\mathrm C$, did you ...
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121 views

What is the difference between thermodynamic and empirical temperature?

When I've studied Thermodynamics I did so in Callen's book and there the author talks about temperature as a single thing, which mathematically is simply defined as: $$T = \dfrac{\partial U}{\partial ...
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Why do frozen objects have a higher propensity to snap/break cleanly than non-frozen/warmer ones?

Why do frozen objects have a higher propensity to snap/break cleanly than non-frozen/warmer ones?
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1answer
255 views

Chemical Potential as a function of Temperature

I have considered an ideal fermi gas. Then, we can obtain an expression for chemical potential as a function of Temperature. I want to understand the physical significance to it or what it really ...
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Why the breath sometimes warm and sometimes cold? (2 different explanations!)

If you blow air against your hand with your mouth open, you feel warm breath. If you do with with your lips closed except for a small opening, you feel cold breath. One explanation from here says "...
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26 views

Is there a maximum temperature? [duplicate]

I have read about absolute zero. I understand that it is impossible to cool a system below absolute zero (or to absolute zero for that matter). However, is there a maximum temperature? My intuition ...
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1answer
219 views

What causes a heat generating source to stabilize at a certain temperature? (Answered by myself, I think)

For example, we out a heat sink on a microprocessor to keep it cooler. I understand that if we run 100 watts of electricity through the microprocessor, it will generate 100 watts of heat, or 100 ...
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52 views

Proving that the Boltzmann entropy is equal to the thermodynamic entropy

I've been trying to understand how we can equate the Boltzmann entropy $k_B \ln \Omega$ and the entropy from thermodynamics. I'm following the approach found in the first chapter in Pathria's ...
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How do we know the temperature on the planets?

I was watching a show and they were saying that the temperature of Pluto (I know it is not a planet) is about $-300 {}^\circ F$. I know that depends where in the orbit Pluto is, but how do we ...
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1answer
47 views

How can core of Mercury be a molten liquid?

We all know that Mercury's surface temperature varies a lot from day to night, from 427 °C in a day dropping down to −173 °C at night. Mercury has a hot molten outer core inside it. How can it ...
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50 views

Which temperature does $T$ in Clausius inequality ($\oint \frac{\delta Q}T\le 0$) refer to?

I got a little confused about the temperature in Clausius inequality. As you can see in this answer of Luboš Motl, it seems that temperature is the temperature of the system. But in some answers of ...
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Hot water freezing faster than cold water

This question has puzzled me for a long time. There is already a question like this on Physics.SE. John's answer to the question seems quite satisfying. But when I googled the cause I found this and ...
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Celsius to Fahrenheit confusion: why there is no 1 to x ratio?

Why is it not possible to know the ratio of 1°C to how many Fahrenheit and use that to convert from or to Celsius/Fahrenheit? What is really happening? Fahrenheit increases linearly and so does ...
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1answer
29 views

Are there any industry usage for gas thermometer? [closed]

I've been searching on this for a while now. Are there any specific advantages and disadvantages for using gas thermometer? Are there any specific industry usage for this kind of thermometer?
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Where does this data comparing the CMB with Eddington's 'temperature of space' come from?

Eddington estimated the temperature of space assuming that star light would be scattered by interstellar dust. He came pretty close to the temperature of the CMB. http://www.astro.ucla.edu/~wright/...
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180 views

What is the overall rate of heat conduction through two pipes of different dimensions if the thermal conductivity is not constant?

I am trying to work out how I would find the rate of heat transfer through two pipes made of the same material that are joined at their ends but which have different cross-sectional areas and lengths. ...
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1answer
126 views

Dynamic response of temperature change when identical fluids flowing mix together

As shown in the below figure , there is a mixing of a fuel in a system. the mass flow rates m1,m2 are different, the pipe diameters are all equal but are different in length.I need to get the ...
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2answers
486 views

What is characteristic time in Fourier number exactly?

What is characteristic time in Fourier number? How can I calculate characteristic time? Suppose I started heating water in a closed container by immersion rod and temperature increases continuously....
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How does the entropy change during the cooling of a hot coffee in a cold cup?

The second Law of Thermodynamics states that entropy always increases in the universe: things become more disorganised. This means, that if I have a hot coffee in a cold cup, then the heat will ...
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2answers
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Is it possible for an object to have low specific heat capacity and low thermal conductivity?

As I see, there are many examples of object with low specific heat capacity and high thermal conductivity and vice versa. Since they are different properties of matter and their definitions are not ...
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3answers
68 views

Heat Pumps and COP?

Heat Pump COP (Coefficient of Performance) $$COP=1-\frac{T_c}{T_H}$$ With Heat Pumps is the efficiency/COP more dependent on the hot or the cold reservoir and why?
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113 views

Does temperature affect to movement of electrons?

Does temperature affect to the movement of the electrons circulating the core of an atom? Do they move faster if temperature increases?
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42 views

Is the vacuum state of a quantum field necessarily zero temperature?

A statement in Quantum field theory: zero vs. finite temperature points to temperature as it relates to the vacuum as being a matter of definition. In that post, Will states By, "at zero ...
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1answer
48 views

Thermal expansion of both liquid and glass tube

I'm a bit confused about thermal expansion in the case in which both a liquid and the container do expand. I will describe an example situation to expose the problem. Consider a cylindrical glass ...
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Removing temperature from black hole

Suppose I take the metric of a three dimensional AdS-Schwarzschild black brane (Note not actually a black hole!): $ds^2 = \frac{L^2 dr^2}{r^2 W} + \frac{r^2}{L^2} \left[ - W dt^2 + dz^2 + dx^2 \right]...
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Does sound propagate further in freezing weather?

A few days ago I went for a walk in the evening. We're having winter with a little snow and freezing temperatures. We're in a quiet, shallow valley with a train station about 1km from us. I heard a ...
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Temperature of Bose-Einstein-Condensate in space

Recently I heard a talk by Bill Phillips, who talked about the coldest temperatures in the universe. Among others, he sayed that the coldest temperatures created at the moment are BECs, which can ...
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309 views

Specific heat capacity and temperature, 0 K?

I've found similar threads like this, but with no clear answer. I understand that the specific heat capacity of a substance increases with temperature, because the vibrational nodes and rotational ...
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1answer
115 views

Quicker way to cool liquid

I need to prepare a bottle of baby milk from formula quickly. To prepare it I must use some boiling water to sterilise the powder however it must be served at just above room temperature for the baby ...
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44 views

Water + metal + fan = convection cooling?

I'm playing around with the notion of a swamp fan, but I live in a humid climate and have no interest in putting more humidity in my bedroom. Supposing I submerged a rod of metal into a mostly sealed ...
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1answer
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Is there a temperature at which ice is denser than water?

Normally ice would float on water because its density is less compared to that of water as a liquid. But is it possible that its density will increase due to a very low temperature or is ice in any ...
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1answer
844 views

Newton's law of cooling for the heat equation boundary condition

Newton's law of cooling says the temperature of an object satisfies $$ \frac{dT}{dt} = -k(T(t) - T_0),\tag{1} $$ where $T_0$ is the surrounding temperature. See these HTML notes for example. Now if ...
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Why isn't temperature measured in Joules?

If we set the Boltzmann constant to $1$, then entropy would just be $\ln \Omega$, temperature would be measured in $\text{joules}$ ($\,\text{J}\,$), and average kinetic energy would be an integer ...
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What is the rate of heat transfer between 25C water and 20C air?

This might be an elementary question, but I was only able to find the formula for heat transfer only in one substance. *Surface area: 1 meter square
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Behaviour of Altimeter at different temperatures

I have realized that the Altimeter of my bike computer (it uses Air Pressure to determine altitude and needs to be calibrated every start) is not consistent at different temperatures. At the Start ...
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0answers
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Does the vacuum have a zero Seebeck coefficient?

I was considering how at very high energies (e.g the Schwinger Limit) the vacuum starts having properties we would normally associate with "materials", such as non-linear polarizibility. The Seebeck ...
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1answer
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Can the work in a isochoric process be non-zero?

I came up with a doubt regarding isochoric irreversible processes. Question: Is it always true that, for any isochoric process, reversible or not, the work exchanged by the system is zero and the ...
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1answer
151 views

Differences between thermal and non-thermal plasmas

I have a doubt about plasmas which may as well be trivial or very stupid, but I couldn't get a clear and straightforward answer anywhere I looked, and I can't get the grasp of it since I wasn't given ...
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2answers
94 views

Can two different objects or system of molecules have different temperatures, but having same internal kinetic energy?

If I take an extreme case, where a body has only an internal potential energy with zero internal kinetic energy, does this body have a temperature? Another question related to it: if two objects A and ...
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How is a irreversible process (conventionally) represented on a $T-S$ plane and why cannot it be (really) represented?

A reversible process can be represented on a $T-S$ plane, and the area under the curve is the heat exchanged by the system. On $P-V$ plane a irreversible process is conventionally represented with a ...
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3answers
86 views

Thermal energy of a system

If I had a hot cup of tea and I added to it cold milk, what would happen is that tea will lose some of its thermal energy to the milk. But why do we notice that our liquid is no longer as hot as ...
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When water turns to steam at 100 degrees Celsius why does both the internal and potential energy increase?

I thought during this transition only the potential energy increases as energy is used to weaken the van Der Waal forces between the molecules. And that the internal energy is only dependent on the ...
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43 views

How extremely low temperatures (near absolute zero) are actually measured [closed]

How do the industrial or laboratory thermometers for this purpose work like: what effects are based on, what are other alternatives how accurate they all are
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1answer
23 views

At what rate does a wet clothing decrease the temperature of a human body?

The question is required for my project, but it is frankly too hard for me... The variables that I consider are: Human Body: 36.5(C) Air: 20(C) Sunlight Intensity: 1,368(W/m^2) Wind Speed: 20(km/hr) (...
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7answers
682 views

Relativity of temperature paradox

The imagined scenario: Part A: From special relativity we know that velocity is a relative physical quantity, that is, it is dependent on the frame of reference of choice. This means that kinetic ...
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2answers
70 views

What is the time required for water at 10 deg C to reach room temperature?

I have a small container (100mm X 80mm X 60mm) filled with water at 10° C. The container is made out of Aluminum and is not insulated, and is resting on a wooden table. Room temperature is about 27° C....
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1answer
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How are extremely high/low temperatures achieved on Earth?

Low Temperature Superconductors (LTS) have their critical temperature below 30K. How are they cooled to such low temperatures? The operating temperature of a Tokamak is greater than 10 keV (over ...
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1answer
35 views

Water Boiling Time Calculator

Is there a way to calculate out how quickly a body of water will boil? My primary concern is to measure in relationship to different temperatures. For example, heat at 100 degrees Fahrenheit versus ...
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Compressed air in a volume: Can I determine its temperature?

Using a compressor, I augment the pressure in a volume (using atmospheric air). I only measure the pressure inside. I now that the density will increase however, the temperature decreases. Can any one ...