# Questions tagged [temperature]

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.

2,034 questions
Filter by
Sorted by
Tagged with
47 views

### Derivative expansion in hydrodynamics and the definition of the temperature

Thermodynamic quantities are well defined at equilibrium. a fluid at zeroth order can be approximated by a perfect fluid and conserved currents such as electric current and energy momentum tensor is ...
47 views

### Overall heat transfer coefficient

I'm trying to design a liquid fueled rocket engine, with copper walls cooled by kerosene. While designing it, the following formula comes out: $$Q=qA=wc(T-T(0))$$ Where: Q = total heat transferred ...
40 views

### What is meant by the temperature of an atom? [duplicate]

Does it make sense to ask 'what is the temperature of an atom?'. Why not?
18 views

### Operation Of A Constant Volume Gas Thermometer

Concerning the mechanism of a constant volume gas thermometer, I was wondering how the adjustment of the second tube upon the open side increases the pressure. I know how the gas placed in the ...
79 views

### Can regular air conditioner be used as heater? [closed]

In winter season, the normal room temperature is generally 6 to 10 degree Celsius, if the air conditioner is working at 25 degree Celsius will it be working as a heater, making the room warm (relative ...
80 views

### Surface temperature variation with distance [closed]

So here is the question I'm troubling with: We estimate that the temperature varies approximatively with that relation:
57 views

### Why doesn't the phonon theory reproduce a Debye-like curve for $C_V$ vs. $T$?

Debye's theory is a model of specific heat in which a high-frequency cut-off $\omega_D$ is put in by hand. The resulting curve of $C_V$ versus temperature $T$ grows as $T^3$ at low $T$ and saturates ...
93 views

### After I pour a cup of tea, I can't drink it for 10 minutes. Will it stay warmer if I add the milk at the start, at the end or does it not matter? [duplicate]

So preface, I work in engineering so I'm familiar with the basic principals of most fields in physics, but specialise in Civil Engineering so my knowledge of thermal physics is poor and I haven't ...
41 views

### Deriving partial differential equation for temperature using conservation laws and constituent relations

I want to derive the partial differential equation for the temperature T as $$\partial_t T(t,x) + v(t,x)\cdot \nabla T(t,x)=0.$$ Quick note: I'm doing a mathematics major, and so I do not really ...
267 views

### Can anyone explain the REAL reason why CO$_2$ increases global temperatures (not the simplistic greenhouse analogy provided for public consumption)?

The greenhouse effect analogy of global warming is that atmospheric carbon dioxide CO$_2$ absorbs some of the infrared radiation emitted by the Earth, and redirects a portion of that radiation back ...
54 views

### Is there a net increase of temperature in thermal equilibrium? [closed]

If I have two objects sitting side by side let's say a water pump running at 10 degrees c and a processor running at 50 degrees c. The heat transfers from the hotter to the colder object until they ...
34 views

### Is it possible to estimate the composition of a mixture between ice and liquid water from a temperature heat graph? [closed]

I'm confused whether the equation for thermal equilibrium can be used to obtain the composition of a mixture with only having as information a graph. This happened when I attempted to solve a problem ...
35 views

### Thermal diffusity. What do I use? [closed]

I'm not a physics expert. Actually don't know much at all but I'm trying to find an answer to a problem. If I had a silicone (or clear vinyl if more appropriate) tube with .25 inch interior ...
99 views

### How can gravity increase $p$ without increase of $\rho$ or $T$? [duplicate]

A point in static fluid has pressure of $\rho$ * g * h, where $\rho$ is the constant density throughout the fluid body, g the gravitational accelaration, and h is the height of the fluid column above ...
30 views

### Temperature raise in glass due to an electronic circuit on top of it

I have a glass substrate with an absorbing layer on top, This layer acts as a LED. This device will eventually sit inside a vacuum chamber with no ventilation and I'm worried about the temperature ...
39 views

### Does the shape of the Higgs mexican hat depend on the temperature of the universe?

I am reading this paper and i wonder if it is mainstream. Does the VeV of the Higgs field evolve with time? What about the mass given to the fermions?
67 views

### Gaussian (CGS) unit of temperature: is there a statkelvin?

In the Gaussian (CGS) system of units, the unit of electric charge (statcoulomb) is derived from the units of length, mass and time. Using Coulomb's law, we find that the dimension of electric charge ...
19 views

### Temperature difference of thermoelastic bodies [closed]

Let $B$ be a "very thin" tridimensional deformable body of the form below. Let $T_0$ be the temperature of $B$ in the reference state. Let $T(x,y,z)$ be the temperature at a point $(x,y,z)$ of the ...
16 views

### Temperature dependence of rubber elastic modulus

Why does the elastic modulus of rubber increase with temperature? I read the article on rubber elasticity and it showed that the modulus increases with the temperature (rubber shrinks as heated). But ...
25 views

### Calculate the rate of cooling of huge amount of water to room temperature

Is it possible to calculate the rate of cooling of huge amount of water to room temperature given the following parameters: The surface of water in contact with air the surface of water in contact ...
63 views

### Does the same temperature imply the same translational kinetic energy?

So I basically have three inter related questions. Is temperature a measure of average kinetic energy (both components) or specifically the translational kinetic energy component? Is it correct (...
4k views

### Bush fires and heat waves, the real mechanics?

Like many others, I have been following the sad development of the bush/forest fires in Australia recently. A claim that gets repeated is that one of the contributors to this blaze is the ongoing >45°...
169 views

### Why does the second law of thermodynamics prevent 100% efficiency?

So far in my thermodynamics lecture course, my understanding of the laws of thermodynamics is that the first law is about the conservation of energy, the second law says entropy must always increase ...
102 views

### How to assign a temperature and a time to cosmic events in the universe?

Sorry if this question to too silly for the experts here. But how do cosmologists assign a temperature and a time to each important cosmic event in the history of evolution of the universe such as ...
40 views

### The temperature of the chamber B

I am studying Thermal Physics and this question raised from a problem I was work on. I don’t want to know the answer, I want to understand it in a conceptual and logic way Suppose we have a chamber ...
12 views

### Marangoni flow explained

Following this article, I want to understand more about Marangoni flow. So from what I get so far, there is a difference in temperature at a point in a solution and that create temperature gradient ...
51 views

### Why is Methane a more effective greenhouse gas compared to Carbon dioxide? [duplicate]

Over 100 years, Methane has a Global warming potential 34 times bigger than Carbon dioxide. Over 20 years, it's even 86 times bigger. How does one arrive at these numbers? Looking at the following ...
72 views

### Regarding directional derivatives [closed]

we know directional derivatives are the rate of change of any given scalar field along the given direction, and it is also equal to scalar product of gradient of the field and the unit vector along ...
25 views

### Is temeperature dependent on reference frame?

temperature is defined as the average kinetic of particles and as velocity is relative them the magnitude of temperature must also increase. Is it so? If I move an object/gas container at constant ...
15 views

### How to calculate radiation pressure?

The radiation energy flow from a heated body is given by: $W = σT^4$ $W$ is power by area: $(dE/dt) / A$ For EM waves $E = cP$, where $P$ is momentum. So $W = σT^4$ = $c(dP/dt)/A = c(F/A) = cp$,...
73 views

### Temperature and kinetic energy of molecules

I was wondering if temperature is related to the average translational kinetic energy of the molecules then why does the average kinetic energy of say a moving object not affect the temperature? What ...
59 views

### What is a cold black hole in astrophysics?

I found the word 'Cold Black hole' in some academic papers. I think it is concerned with thermodynamics of black hole but I don't know exactly what is cold black hole. Please help me to understand ...
48 views

### Does temperature affect how things slide on a slope?

Imagine I have a stainless steel slide and I roll a marble down the slope. My question is, would the marble roll down any slower or quicker if I change the temperature of either the marble or the ...
70 views

### Everything will not just turn into vapor in the ground zero of nuclear explosions but hydrogen plasma

Calcium atoms can't withstand extreme heat according to this link. http://abyss.uoregon.edu/~js/ast122/lectures/lec09.html "Why do some stars have strong lines of hydrogen, others strong lines of ...
31 views

### What is the growth factor influenced by?

If I model the cooling of a cup of coffee with the differential equation $$T'(t)= -a(T(t)-U)$$ where $U$ is the surrounding temperature and $T(t)$ the temperature of the coffee after $t$ minutes. ...
51 views

### Can 40Ca II decay or change into something different

I just read the Wiki article on calcium isotopes and it said the stable calcium isotopes such as 40Ca have never been observed to decay. Then, despite the high temperature of stars such as Sun there ...
53 views

### How does hot air affect power required to move a car?

I recently posted an answer to Sustainability StackExchange where I claimed that energy consumption for cars (specifically, for electric cars) with no air conditioning drops when it's hot. The reason ...
35 views

### Unit Conversion with Temperature and Mixed Dimensionality

So, I understand the relationship between K(Kelvin), R(Rankine), C(Celsius), and F(Fahrenheit), and the complications of converting between them (i.e. varying meaning of zero). However, when ...
85 views

### What is QFT at finite temperature?

On the one hand, according to the Wick rotation that relates Statistical Field Theory and Quantum Field Theory, a finite temperature statistical system corresponds to a compact time quantum field ...
75 views

### Why temperature of planets decreases as we move far from Sun?

Is there a friction in the space? If yes, then does that affect speed, wavelength and amplitude of an EM wave? And i also want to know, why temperature of planets decreases as we move far from Sun?
48 views

### In Jacobson's theory, space is thermodynamic. But what about the temperature of electromagnetic radiation?

Following Jacobson ( https://arxiv.org/abs/gr-qc/9504004 ), Padmanabhan, Verlinde and others, space is due to microscopic degrees of freedom. They are unspecified, but have temperature and entropy. ...
41 views

### Air cooling vs Temperature

If its $35^{\circ}\text F$outside, Will my electric heat come on more often to maintain a room at $78^\circ \text F$ compared to $65^\circ \text F$? Not including the initial time it takes to heat ...
76 views

### Do electrons have intrinsic speed?

Absolute zero is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion. At absolute zero ...
35 views

### Can a system cooled to absolute zero become trapped in a local minimum of energy?

Suppose I have a diatomic molecule with a potential function $V(x)$ depending on the distance between the atoms. Suppose also that this function has exactly two minima, one global at $x_1$ and one ...
43 views

### Explain Imaginary Time and Temperature [duplicate]

I was amazed to learn that we can use Imaginary unit iota into physical quantities like time and Temperature but how exactly? The explanation was not something I would say stellar so I am hoping can ...
55 views

### Solid discs and coeff. thermal expansion mismatch

Consider a solid disc of radius $R$ and height $h$ which we glue onto an infinite plane surface. If we now change the temperatur and the assume that the (linear) thermal expansion coefficient of the ...
49 views

### The Definition of Temperature in a Statistical Manner

I am new in thermal physics and I started studying recently the canonical ensemble. Until now, I understand that, in thermal equilibrium, the temperature and energy content of two systems placed in ...
78 views

### What is the history behind defining temperature as measure of hotness? [closed]

I know that when two bodies of different temperature are kept in contact "heat" flows from hotter body to colder. But how did anyone know that it is the "hotness" that flows, one could have said that ...