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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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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0answers
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 ...
3
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0answers
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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1answer
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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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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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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20 views

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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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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27 views

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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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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0answers
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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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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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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0answers
26 views

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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0answers
26 views

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
56 views

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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0answers
49 views

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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1answer
45 views

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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0answers
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
25 views

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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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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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
48 views

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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1answer
39 views

Why don't solstices coincide with temperature extremes? [duplicate]

In northern hemisphere, the highest temperatures are usually in July — in the middle of calendar summer. See e.g. the climate chart on this wikipedia page. But the solstices are on 20-21 of June, ...
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2answers
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Reversible processes in which mechanical or thermal equilibrium is not reached

The definition of a reversible thermodynamic process requires in any instant the mechanical equilibrium (equal pressures) and thermal equilibrium (equal temperatures) of the system in a quasi-static ...
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2answers
57 views

Change in entropy of thermodynamic environment during isobaric or isochoric processes

When an ideal gas follows a isobaric or isochoric transformation (no matter if it is reversible or not) I'm not sure what is the change in entropy of the thermodynamic environment. First of all, ...
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0answers
44 views

Why do fans produce cold air currents when they spin? [duplicate]

This was basically an exam question on first year medical students in the Medical Physics class and I couldn't answer it based on my background and pertinent preparation. The topic asked the candidate ...
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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
53 views

Confusion on electron volt and Kelvin?

If an element A has a binding energy of X eV with element B, can it be said that it is equivalent to X*11600K as 1 eV approx equals 11600K. I do not think this is correct as temp. is linked to the ...
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0answers
32 views

How can one calculate the drop in air temperature associated with a rise in its humidity?

Background: I wish to model the effect of an evaporative cooling system in a humid, tropical environment to be used as a feasibility study. Anecdotally, such a system would be ineffective, but I would ...
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2answers
94 views

Why is water not considered a proper liquid in terms of thermometers?

We were just discussing about why liquids in general are used in glass thermometers. I was wondering why water isn't considered a proper liquid. Is it because of the way is expands differently to ...
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1answer
119 views

How are thermometers calibrated?

I know this is quite vague, but I was just thinking about it......like obviously now we mass produce things and we don't really think about them. But how was the first thermometer calibrated/how are ...
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Why does temperature change the friction coefficient of my stovetop?

I have a Ceran cooking field at home, it's a glass-ceramic surface with heating coils embedded beneath. When I slide a pan around there's much more friction on a hot plate than on a cool one. Why? ...
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0answers
29 views

Implementing fixed-temperature, solid-wall boundary conditions

I wish to simulate the behaviour of a fluid along one dimension, where the right boundary is transmissive and the left boundary is a solid wall at a fixed temperature. Temperature is not one of my ...
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0answers
61 views

Thermodynamics: Apartment Airflow: What Am I doing wrong air

Our apartment is a sauna. But sometimes it's much much hotter inside the apartment than it should be (night time it's 68 degrees outside but thermometer still says 90 inside!). I have 2 fans, one ...
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1answer
27 views

Thermal equilibrium - magnetization [closed]

The electronic ground state of neutral sodium atoms in a magnetic field splits into two no longer degenerate energy states. In the thermal equilibrium the occupation probability of the states is the ...
0
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1answer
70 views

What are the problems in the idea that a person would freeze to death in outer space?

It is said that the body would freeze to death, if left in outer space, which is true, since the temperature is around $3$K. But what are the flaws in this theory, in terms of thermodynamics (if we ...
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1answer
57 views

How do we measure the temperature of vacuum?

Afaik. temperature is in relation with the kinetic energy of the individual molecules. In vacuum there are only a few molecules so measuring their kinetic energy is very hard, because vacuum has a ...
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2answers
69 views

Is there a way to make atom move faster without heating them?

The more heat you add the faster the atom will move. This is something that is common knowledge. My question is it possible to make the atoms in let's say a gas move faster without adding heat of a ...
2
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3answers
54 views

Gas pressure within containers [closed]

If, hypothetically, a gas had no inner pressure, and it was made to fill up a container. If, then, the pressure within the container was increased by filling it up with yet more gas, until high ...
0
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0answers
28 views

Temperature of a single dipole [duplicate]

When taught about the temperature of a system from an illustrative point of view, I was told to think of molecules vibrating and hitting one another. If the molecules vibrate faster and faster (and in ...
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0answers
30 views

Temperature dependent chemical potential

Chemical potential is determined by the number of electrons in the system and coincides with the Fermi energy at zero temperature. The chemical potential can shift as temperature changes if the ...
3
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1answer
84 views

Why thermal conductivity increases with temperature?

what is the molecular mechanism with which thermal conductivity increases by increasing temperature? at least for metals? I know that heat increases the oscillations of the atoms in the crystal. But ...
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1answer
67 views

How cold does this ice have to be to freeze this water bottle solid?

We are at sea level in a room that is 21 celsius. We have 1 liter of sterile water with a temperature of 21 celsius in a normal plastic bottle. We have a 20 liter bucket of ice cubes, consisting of ...
7
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3answers
654 views

Cooling down to absolute zero by radiation

Consider a system consisting of a gas, it is put in a container which is permits transmission of all kinds of electromagnetic waves. If this system is isolated and put in a perfect vacuum, and left ...
2
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2answers
69 views

How much faster are airmolecules going when the temperature raise from 15 to 25 degrees C?

As far as I know the temperature of the air depends on how fast the airmolecules are moving. But what is the increase of speed (in km/h) of those air molecules?
3
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2answers
65 views

Blocks releasing heat energy [closed]

If you had two blocks, two different sizes yet the same temperature. Which one would release the most energy in the shortest amount of time and why?
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3answers
114 views

Will most solid state of something also be the coldest? [closed]

It is said that when something is cold its molecules have low kinetic energy, how is that different from something in a solid state. ... The coldest theoretical temperature is absolute zero, at ...