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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24 views

Thermodynamics of a rubber band

I have a streched rubber band and I know that tension f is proportional to the temperature T when the length is constant. How can I proove that internal energy is only a function of temperature? I ...
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1answer
66 views

Why is there zero point energy at absolute zero temperature? [on hold]

If we define the absolute zero as a temperature which there is no entropy in it so why should we have zero point energy?
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0answers
43 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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1answer
19 views

Will a thermometer successfully be able to measure the temperature of this?

In a hypothetical experiment, I would be measuring the temperature change over time of a system; however, there would be no liquid (mostly gas). Would a regular thermometer (probably digital, as ...
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0answers
16 views

Thermistor calibration - estimation of number of reference temperature points needed

A thermistor changes resistance with the temperature in a non-linear way and follows the exponential Arrhenius equation. Two reference points, ice slush water and boiling water, are used for ...
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1answer
22 views

The difference in how temperature feels inside in the summer vs. in the winter?

72 degrees feels cooler when it's hotter outside, say 90 F but warmer if it's really cold outsid, say 32F However it also feels different if it's 90 vs say 70F outside. Why is that?
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80 views
+150

Thermalization of coupled classical oscillators

I would like to understand if it is possible to perform an experiment, where a bunch of classical harmonic oscillators (e.g., LC circuits or mechanical pendula) coupled in a simple manner (e.g., one ...
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0answers
31 views

Canonical or microcanonical ensemble?

What of this ensembles is more honest with natural thermal equilibrium? In microcanonical ensemble the sample is isolated, and we don't now the precise value of energy. By this considerations we have ...
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2answers
34 views

In the Ideal Gas Law, what does “fixed amount” of gas mean?

Does it mean mass? If so, wouldn't Pressure/Temperature basically represent its density?
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2answers
54 views

How does temperature relate to the kinetic energy of molecules?

In ideal gas model, temperature is the measure of average kinetic energy of the gas molecules. If by some means the gas particles are accelerated to a very high speed in one direction, KE certainly ...
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2answers
51 views

How to calculate temperature of an incandescent bulb filament?

Suppose we have a light bulb, for which we know its power rating, like voltage of $12\mathrm V$, and power consumption of $10\mathrm W$. We also know it's a halogen bulb with a tungsten filament ...
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0answers
17 views

Thermodynamics of a heated enclosure [closed]

i have to maintain an aluminum enclosure of size 200x300x400mm at around 80 degrees Celsius, there for i need to calculate the thermodynamics of the system, ie what power of heater i need to achieve ...
2
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1answer
118 views

If we go to space why isn't the temperature high? [duplicate]

We know that the temperature in space (which has vacuum) is low. If I go to space will I feel sweaty and hot or chilly? I think I will feel sweaty and hot because the radiation (UV, IR, etc) of the ...
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1answer
32 views

Temperature and Renormalization Scale in QFT

A particle physicist told me that everything in Peskin & Schroder is at zero temperature, and once you consider finite-$T$ QFT, things become more complicated. Meanwhile, I sometimes see people ...
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2answers
87 views

How long does it take for water to boil when subjected to intense heat?

I have a rather odd question that may just boil (sorry) down to a fairly simple problem I can't solve. The scenario is this: A person is testing the intensity of a super-focused beam of sunlight in a ...
1
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0answers
33 views

Square of velocity = 2 times temperature times specific heat capacity ; seems too tidy [closed]

So I did some algebra and came up with the following $v^2 = 2Tc$ where $ v = $ average velocity of the particles $ T = $ tempreture $ c = $ specific heat capacity but this seems too tidy
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2answers
65 views

What unit system does Fahrenheit belong to?

Wikipedia's page for Imperial Units does not list Fahrenheit. The corresponding page for SI Units lists Kelvin as an SI unit, and Celcius as a derived SI unit. This leads me to believe that ...
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0answers
7 views

Superconductivity induced by magnetic flux or temperature fluctuations (+/-)

Does anyone know of an experiment with magnetic flux rotations that can make a difference in local temperature? I would really appreciate it, I need it for my theoretical model of some things and ...
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1answer
19 views

How do I determine the temperature of a fluid that was x degrees mixed with another fluid of y degrees?

Let's say that I have two, different fluids that are miscible and are of two different temperatures. How can I calculate the temperature of a mixture of the two fluids? Without a thermometer, of ...
-1
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1answer
25 views

Specific heat ratio range [closed]

I know that the specific heat ratio, $\gamma$, exists in the range $1 <\gamma< 2$, and I am required to demonstrate a proof of this. I have come across the following proof (but I don't really ...
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1answer
22 views

General relation between power density of any engine and dissiapation rate and temperature

Many years ago ( before my university studies ) I read that renewable resources are fundamentally limited by laws of thermodynamics to produce energy very slowly (low specific power or power density) ...
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2answers
53 views

Violently shaking object

Would violently shaking something cause a temperature change? For example, if a container of water was shook violently enough; would it be possible to make it boil?
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2answers
1k views

What happens to a body, initially at 300K, kept in isolated space? Will it's temperature drop to 0k?

With regards to Thermal Radiation, given a stable body initially at 300 Kelvin placed in isolation, after continuous Thermal Radiation will it's temperature gradually reduce to 0 kelvin ...
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1answer
45 views

Converting $F^2$ to $C^2$

I'm trying to convert Fahrenheit squared $F^2$ into Celsius squared $C^2$. I know how to convert a value $x$ in $F$ into $C$ with: $\frac{5}{9}(x - 32)$ I also know how to convert a value $x$ in ...
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0answers
25 views

Water as heat source in a heat pump

Consider we have water flowing in a pipe, which is working as a hot source for a heat pump. We are able to know the temperature of the water in both ends of the pipe, yet we don't have information ...
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0answers
9 views

Altitude altimeter application

What is the most precise formula to calculate altitude and what parameters should i considet such as pressure, temperature, dew point, ... I am developing an altimeter app and i don't know what the ...
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0answers
13 views

Temperature Frequency relationship for gas?

I am getting something like this T (C) = Constant*log(Frequency) I do not have background of physics and I am wondering, if there is any formula which can explain the physics behind it? Something ...
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3answers
112 views

Unit consistency

Does $^\circ\mathrm{C}^2$ have any physical consistency? I know that $\mathrm{K}^2$ is a valid unit even though I don't know in which context it can be used. But I feel strange about ...
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1answer
42 views

CMB anisotropy, temperature and doppler effect

How would you derive the following equation: $$ T' = T_{CMB} \left( \frac{\sqrt{1-v^2}}{1+v\cos{\theta}} \right) $$ which describes how the temperature of the CMB varies due to the speed $v$ of the ...
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0answers
8 views

How do I calculate temperature diffusion in a gas contained in a heatsink?

To simplify the problem, consider a sphere with a diameter of $25\mathrm{mm}$ inside an infinite heatsink at $300\mathrm{K}$. At $t=0$ I instantaneously raise the temperature of the gas in the ...
2
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0answers
43 views

Is it possible to efficiently extract phonons from a lattice?

The population inversion generated in lasers occurs in multi-level atomic systems. As an example, the Nd:YAG energy diagram is shown below. The pump pushes the Nd ions up to the upper levels, and ...
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2answers
56 views

relationship of number of standing waves with Temperature?

If we have let us say fixed air column of length 'L', in a open-closed column problem, lamba is equal to 4*L/(2n-1). n = number of nodes / anti nodes in air column How does 'n' changes with ...
4
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1answer
39 views

PP Chain and CNO cycle relationship

At what temperature would the energy generation rates of the PP-Chain and CNO cycles be roughly equivalent? The dependences are so vastly different that I am wondering how and by what equations they ...
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0answers
39 views

Superfluids (meaning, properties)

I am curious as to what a superfluid is? I have seen videos that say that they have zero viscosity, and I know that it means that there is no friction between the layers of the fluid. But what is its ...
2
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3answers
221 views

Why does the system move until equal temperatures are obtained?

In my college level thermodynamics class, the teacher gave us the example of a closed system which consisted of a box thermally insulated. A piston fully divides the box in two parts, and each is ...
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1answer
41 views

Temperature in a vacuum made in the lab

Is the thermal energy of a vacuum 0? And, how close to a perfect vacuum can we make in the lab?
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1answer
33 views

The meaning of the temperature in the Shockley Equation

In the Shockley equation, which is the model of the $I$-$V$ curve of a p-n junction, what does the Temperature refer to, carrier temperature or lattice temperature? When a p-n junction subjected on a ...
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1answer
83 views

How to heat water to 80°C? [closed]

I'm trying to figure out an easy water to get 80°c to consistently make the perfect cup of coffee. Let's assume room temperature water is 22°c. What is the ratio of boiling water to room temp water ...
2
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2answers
42 views

Is there any relation between temperature dependence of resistance and fermi energy in metals?

Given that the resistance varies linearly with temperature in metals, is there any way we can calculate the Fermi energy from this information?
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2answers
41 views

What is the theoretical instantaneous temperature of a gas?

When we measure the temperature of a gas we typically integrate the molecular collisions and wind up with an 'average' temperature due to the sensor comprising a relatively large thermal mass. And ...
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3answers
211 views

100°C = 100 K =?

I'm in first year. Our class is in lesson " Heat and Thermodynamics". While solving a numerical problem of a reversible engine he told us that 100 degree Celsius is equal to 100 kelvin. I inquired but ...
2
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0answers
34 views

100°C =100K = how? [duplicate]

I'm in first year. Our class is in lesson " Heat and Thermodynamics". While solving a numerical problem of a reversible engine he told us that 100 degree Celsius is equal to 100 kelvin. I inquired but ...
3
votes
1answer
86 views

Number $g(T)$ of relativistic degrees of freedom as a function of temperature $T$

Let us consider the total number of relativistic degrees of freedom $g(T)$ for particle species in our universe: $$g(T)=\left(\sum_Bg_B\right)+\frac{7}{8}\left(\sum_Fg_F\right)$$ Where the sums are ...
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1answer
58 views

why doesn't liquid metal vaporize in a vacuum?

I am wondering why molten metal in a vacuum of electron beam and machines never turns to gas like liquid water does when exposed to a vacuum.
3
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2answers
53 views

How do you calculate/estimate hypersonic leading edge and skin temperatures?

At lower speeds (below Mach 5-ish), stagnation temperature (TAT) is a very accurate proxy for skin temperature. But at mid/high hypersonic speeds (especially in the thin upper atmosphere where mass ...
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0answers
27 views

How water anomalies affects the Mpemba effect?

I understand basic explanation of Mpemba effect like this: Distant molecules are easier to realign into new formations. But if we compared two bottles of water like in Mpemba effect and one of them ...
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4answers
62 views

Fall in temperature due to expansion

The following lines are from my book. The gas is heated and allowed to expand at such a rate that the fall in temperature due to expansion is less than the rise in temperature due to the heat ...
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0answers
69 views

How does a heated constant volume flow behave, for an expanding flow tube leading into the free atmosphere

I have a helium gas flow with a flow rate that has been set to a constant value ($0.3\,m^3/h$). It's streaming upwards in the picture, and beyond the upper big red dot position, it meets the ...
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0answers
30 views

An interesting question on the mass of a droplet of liquid experiencing the Leidenfrost Effect

Background and Inspiration: I have seen numerous demonstrations of the leidenfrost effect, both on the internet and in my mother's kitchen. But I started wondering about a general case after having a ...
3
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1answer
71 views

Why is my breath hot when i open my mouth all the way, but cold if I blow like a whistle? [duplicate]

I observed this as when I want to cool my soup I blow like a whistle and when I want to warm my hands I open my mouth more as my breath is warmer now.