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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Is Feynman talking about the Zeroth Law of Thermodynamics?

In Volume 1 Chapter 39 of the Feynman Lectures on Physics, Feynman derives the ideal gas law from Newton's laws of motion. But then on page 41-1, he puts a caveat to the derivation he has just ...
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56 views

Question on finite temperature field theory

In quantum field theory at zero temperature, the expectation values of operators are taken with respect to the vacuum. Is it the case that in quantum field theory at finite temperature, the ...
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90 views

A physicists perspective on a material science/engineering problem

I am looking into some research that involves engineering and material science. As a physicists I wondered what other physicists would think of this problem and how they would approach it. Much of the ...
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184 views

Second derivative of vapor pressure from a cubic equation of state

It is quite easy to compute the first derivative of vapor pressure with respect to temperature from a cubic equation of state at least at the critical point since there is a continuity with the ...
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15 views

How did the radiative flux of each gas giant planet change with respect to time (since their formation)?

We know that each gas giant planet was warmest when it was young. This warmth came from internal heating from both radioactive decay and from gravitational potential energy. This warmth, in turn, ...
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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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25 views

Does the surface of austenitic steels have an especially “dynamic” phase somewhere between 100 and 200 Celsius?

There is lots of kitchen lore about pans. One popular concept are the "pores" of a steel pan surface, which are the reason why food sticks to the pan when it's not heated properly. I don't know much ...
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35 views

Hysteresis in liquid–solid-phase transitions such as Agar

I'm wondering how it is possible for a substance to have a significantly different melting point than its freezing point. What physical interaction "locks" a substance such as Agar into the phase that ...
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71 views

Simple gas in cylinder modeling

I want to do a simple (physically plausible but not physically accurate) simulation of a gas in a cylinder as it works on or is worked on by a piston. Wikipedia gives a good example of an adiabatic ...
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85 views

Does a cooler, submerged in water, keep beer colder, longer?

Looking around the web, I see some submerged bucket-like things, without insulation, and some floating coolers, where the actual cooler is not submerged. Given that your water temperature is lower ...
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84 views

Copper mean free path dependence on temperature

I'm doing simulations of copper, where the temperature can reach up to ~1300 K. Some calculations depend on the mean free path (MFP) of copper. The only value I've found for it is 39nm and it's ...
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25 views

Quantum computing records (storage times)

Long storage times for qubits will be integral in the construction of a scalable quantum computer. This leads me to ask the current state of affairs in our ability to store qubits. Namely, what is the ...
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145 views

How Temperature, Pressure and Altitude are related in the atmosphere?

I'm looking for an approximation for the temperature of the atmosphere at any height and pressure. Both altitude and pressure are known variables, I've derived this equation using maxwell's ...
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125 views

Calculate how hot PLA will become

I am trying to attach the shaft of a brass heating tip to a PLA component. My problem is that the tip will have to reach a temperature of about 200°C and the PLA can only handle a temperature of about ...
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73 views

How can I read density fluctuation from microwaves?

The Cosmic Microwave Background Radiation shows temperature differences. The red and yellow areas are warmer. The green and blue areas are cooler. For example consider this picture of CMBR ...
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575 views

How much power to keep surface of aluminum plate at given temperature?

I want to heat one side of an aluminum plate enough to hold the other side of that plate $100K$ above ambient. I'm willing to assume that the heated side of the plate is "well" insulated (along with ...
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10 views

Thermodynamics of a heated enclosure

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 ...
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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 ...
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26 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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11 views

Given temp and conductivity can I back-calculate to resistance, in order to plug in a new temp value and calculate a more accurate conductivity?

Background: I used a small CTD (conductivity, temperature, depth) recorder to log a series of dive profiles in a mixed coastal estuary. The recorder logged observed temperature and conductivity every ...
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81 views

Negative temperature thermodynamics

I asked this question about thermodynamics. I considered $$T=\frac{\partial U}{\partial S}$$ at constant $V$ and $N$ (number of particles), but now I can't figure out the change of $U$ with respect ...
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42 views

What does the temperature of the early universe tell me?

I am re-reading Weinberg's book "The First Three Minutes". In the Introduction he makes this statement: "At about one-hundreth of a second, the earliest time about which we can speak with any ...
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40 views

Calculation of Water Temperature

In a close looped process the soft water (approx. $200\frac{m^3}{h}$ at $14$ barg) gets heated gradually from the ambient temperature to $\Delta$T of 20°C in $13-14$ minutes, i.e. if amb. temp is 45°C ...
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42 views

unknown stresses in double-layer glass window

I live in cold place where outside temperature drops to -20. Currently, we have -20 and on my window, which is doubled layer glass with trapped air in between, I found a "polarized stress spectrum" ...
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66 views

How is the bandgap reference diode so accurate? (temperature changes bandgap?)

I am studying about bandgap references (wiki). As a black box approach, (from what I know) it can be seen as a system which gives a stable voltage reference irrespective of the highly varying ...
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53 views

Linear decrease in temperature during a redox reaction?

This is physics-related, don't worry. To calculate the enthalpy change of a solution during a redox reaction, what we did in class was measure the temperature of the solution every 30 seconds (before, ...
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113 views

Milk-First School

I have always been struck by the huge amount of different arguments about the issue: When you make a cup of tea, the milk should be poured first or added to the cup after the tea? Wikipedia, ...
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81 views

Temperature of Bose-Einstein-Condensate in space

Recently I heared 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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How do I calculate the speed of a temperature change?

I know how to calculate the change of temperature in a copper wire depending on voltage and current, but not how fast the temperature would change.
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8 views

Temperature of air effused into tank - different predictions?

Consider air from outside at $T_0$ effusing into an evacuated and thermally isolated chamber. By thermodynamic potentials, the temperature inside the tank is given by: $$T_1 = \gamma T_0 = ...
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1k views

Definitions in thermodynamics: temperature, thermal equilibrium, heat

I'm currently reading Fermi's "Thermodynamics" and I'm trying to grasp the (possibly different) right definitions for temperature, thermal equilibrium, heat. To clarify, I'm looking for definitions ...
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75 views

Photon temperature above Electroweak Symmetry Breaking (EWSB) transition

In discussions of the history of our Universe, photon temperature is substituted for time. As the Universe cools, phase transitions break symmetries, including electroweak symmetry. Why does it make ...
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262 views

ideal gas law modelization in a vacuum chamber

I am trying to model a pressure sensor in COMSOL. The basic work is that there is current flowing inside it, if the pressure of the gas around it drops down, the temperature goes down as well (ideal ...
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130 views

How to solve state parameters using these givens for an ideal gas?

In a thermodynamic turbine using air as an ideal gas, given that you have a known inlet temperature value $T_i$, a known exit pressure value $P_e$, a known inlet and exit velocity $V_i$ and $V_e$, a ...
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134 views

“This is not a perpetual motion machine, because reservoir temperatures are changing.” Is it a valid argument?

I've already faced this situation several times: given a statement (in area of thermodynamics) I used it to provide an example of some perpetual motion machine (of first or second kind). Therefore, I ...
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745 views

How to liquefy Hydrogen?

I have got a science project and my teacher has recommended me to do "Liquefying Hydrogen". I have been continuously thinking about that but I have not come to a solution. Can anyone please tell me ...
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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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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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12 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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37 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 ...
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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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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 ...
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52 views

How does one calculate the applied magnetic strength of a superconductor?

How does one calculate the applied magnetic strength of a superconductor? I spoke with a faculty member about this question. He explained to me that if one can break the spin pairing of two electrons ...
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34 views

What are the Fermi and Debye temperature constants?

What are the Fermi temperature and Debye temperature constants? We were discussing these in class and I don't fully understand what these constants are or why we have them. Can anyone explain?
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15 views

Trying to determine transient response of air conditioned room

I have an air conditioned room which intakes airflow at temperature $T_{in}$ at a mass flow rate $\dot m$. The air leaks out of the room at mass flow rate $\dot m$ and temperature $T_{room}$. The room ...
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46 views

Constant volume gas thermometer

Well, in the notes I took in thermodynamics' class I have a graph that plots Pressure of boiling point $P_b$ over Pressure of freezing point $P_f$ at constant volume in terms of Pressure of boiling ...
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37 views

Temperature as the independent variable of Lagrangian

I was thinking about applications of the Lagrangian and I started to toy with some ideas and tried to come up with interesting twists. Immediately I thought it would be interesting to use temperature ...
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20 views

PT100 calibration

I have also asked this on the electronics group, but it is equally relevant to physics of temperature mearurement If I take (say) a class B PT100 sensor with a stated absolute accuracy of +/- 0.3 deg ...
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41 views

Effects of pressure rate of change on the temperature of a fixed amount of gas

In Vol I,Chap 1-2 of the Feynman lectures on Physics,Feynman talks about how a change in pressure of a fixed amount of gas enclosed in a piston can cause its temperature to increase/decrease. He ...
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The initial presumed temperature of the universe is derived from data?

When people mention the BBT (*) they assume that it is hot. As late as 1988 it was scientifically proposed a cold BB model (WP) The initial presumed temperature of the universe is derived from ...