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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.

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What exactly is temperature?

I'm trying to have a really deep understanding of quantum physics and so I went back to what is blackbody radiation until suddenly I realized that my understanding of temperature is that of... well, ...
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Does the critical dynamical exponent z of a 2D Ising model (simulated with Metropolis) vary with the temperature?

I have found in the literature that the critical dynamical exponent $z$ of an Ising model simulated with a local algorithm (such as Metropolis) is something around 2 near the critical temperature, ...
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Temperature distribution with advection problem

A very long pipe enters an oven at $x_1$, with oven temperature set to $T_{\infty}$. Fluid flows through the pipe at mass flow $\dot{m}$ (flow speed is $v$), initially at temperature $T_0$. Flowspeed ...
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Why don't you get burned by the wood benches in a sauna?

When you go to the sauna you may sit in a room with 90°C+. If it is a "commercial" sauna it will be on for the whole day. How does it come that when you sit on the wood you don't get burned? I ...
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Human perception of temperature

I had the following thought experiment recently: Suppose we have a vibrating plate for which we can tune the amplitude and frequency of vibration, and imagine we hold a finger against the plate. For ...
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Express work in terms of linear thermal expansion? [on hold]

I have the following problem. Below are two approaches that came up as a solution. the second one is not mine. I feel confused by the question.I need helped in answering the problem. here it should be ...
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Thermodynamics trick question [closed]

My professor mentioned this in class as something to think about, but I can't figure it out. The riddle goes: If a bucket of water is standing in a shop window where the sunlight shines through, ...
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Is there a difference between the red sky in the morning and in the evening?

It certainly has a different feeling to it, but does the temperature or earth's rotation or the clouds or anything else really make it two different physical phenomena or at least different colors? ...
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Why hot soup is tastier than cold soup? [closed]

My physics teacher recently asked me this question. Can anyone answer the question?
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Please help me in solving this question [closed]

An atom has two energy levels with a transition wavelength at 5800 Å. At room temperature 4x1020 atoms are in the lower state. How many occupy the upper state under the conditions of thermal ...
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How many temperatures has a plasma?

In nonthermal plasma, not all particles move in the same way. The electrons are different from other particles. Both can be described as having a temperature separately. But that would mean, one piece ...
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1answer
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Temperature excursion energy on Mars [closed]

Could we use the high range of temperature excursion on Mars, for example applied on gases or liquids, to produce some usable energy? Let's assume that the day-night excursion is +20 Celsius (day) and ...
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Why is a liquid nitrogen canister not cold on the outside when inside the temp of the sealed liquid is -320F? [closed]

...or IS the inside temperature ambient temperature? Surely the insulation of the container is not sufficient to seal in that cold? I.e. if you had an unsealed bowl of liquid nitrogen with the same ...
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Is the triple point of water exactly 0.01 $\deg$C?

Is the triple point of water exactly $0.01 \deg$C, or is this an empirical value/is there some uncertainty to it? If so, how do we know it is exact, and why?
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How to calculate energy (KWh) from Temperature (T),Air quality (Co2), and illumination (lux)?

I have data of temperature, air quality, and illumination.I want to calculate energy consumption (KWh) from these parameters.My data is shown in the image . Also, examples are also shown in image 2 .
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Is there an influence of the air humidity on the air expansion by a temperature change?

I have found the following formula to calculate the expansion of air by a temperature change, if the pressure stays at the same level: ΔV = ​ɣ * V0 * ΔT This would give me an expansion of 46.96m3 in ...
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If the Sun had a larger surface temperature how would that affect its appearance to us in the sky?

I thought about this when I came across wiens displacement law which says the higher the temperature, the lower the peak wavelength. If the sun was a lot hotter, and its peak wavelength wasn't in the ...
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John Dalton's temperature scale? [closed]

Could some one give me a brief explanation of what Dalton's temperature scale is? I have tried to refer to understand this scale but there are not that much information out there in the internet. ...
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Temperatures of Galaxy Clusters

Recently I've read about clusters of galaxies and have tried to understand how one can measure their mass and temperatures. Clearly, we can physically measure a couple of things such as the flux of X-...
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Relation between Temperature and heat current

This problem: I was able to solve it doing this: But I think i have nowhere " exploited " the equivalence given above. How can this be used in this problem?
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What happens to a liquid nitrogen canister under pressure if left at room temperature? Will it eventually explode? Or forever stay cold?

If I put a strong, sealed container of liquid nitrogen on a table at room temperature, will it always stay cold? Or will it slowly heat up until the canister bursts? Assume it is an extremely strong ...
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What boundary conditions does a steady state initial temperature profile that evolves according to the heat flow equation obey?

A cylindrical rod of length $L$ is insulated over its curved surface. The end of the rod at $x = 0$ is in contact with a heat bath at temperature $\Theta_0$ and the end of the rod at $x = L$ is in ...
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Dependence of melting/boiling on external electric or magnetic fields

$H_2O$ is a rather strongly polarized molecule ($\epsilon_r\approx 80$) and it is also diamagnetic ($\chi_m \approx -9\cdot 10^{-6}$). My question is how does the melting or boiling $p-T$ curve ...
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Are two layers of clothing more effective for keeping warm than one double-thickness layer?

Many sources state that two layers of clothing are more effective than one thicker layer at keeping warm. It is universally argued on the basis that multiple layers give a larger air insulating layer ...
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Why does a dense, hot, opaque body produce blackbody radiation?

I read from a textbook that a dense, hot and opaque body produces black body radiation, for example the heated filament of an incandescent light bulb. Why is it so? The explanation given is if a ...
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Why is bringing two object to their initial temperature an irreversible process?

In the lectures, given in here, it is stated that We can imagine thermodynamic processes which conserve energy but which never occur in nature. For example, if we bring a hot object into ...
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Which one is better to boil water, using high heat or less heat?

Consider that I have a water boiling kettle as below. Assume that it is made of metal, not plastic (but plastic probably also will do). Assuming I can adjust the power it uses to boil the water with ...
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If I leave a glass of water out, why do only the surface molecules vaporize?

If I leave a glass of water out on the counter, some of the water turns into vapor. I've read that this is because the water molecules crash into each other like billiard balls and eventually some of ...
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Absolute Heat With Kinetic Energy

I’ve read some of the questions posted here about absolute hot. Planck’s temperature. I understand that that temp comes from the natural units. Where my question comes into play is when thinking ...
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Why is the change in resistance not directly proportional to the change in temperature?

Change of resistance with respect to temperature is defined as $$\frac{\mathrm{d}R}{R}=k\mathrm{d}T$$ where $k$ is a proportionality constant, $R$ the resistance, $T$ the temperature and $\mathrm{d}R$...
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Horizon Problem: How did different regions of space acquire different temperatures?

I'm trying to understand the Horizon Problem. Inflation describes how non-causally connected parts of the universe (that we see today) could once have been in causal contact. The reasoning goes that ...
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What is the closest distance for an undiscovered old neutron star and how long would it take to get here? To help people scared of neutron stars

This is to help people who are scared of neutron stars. My questions are What is the faintest a neutron star could be How close could it be and not yet be detected How long would it take to get here ...
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Stress in a rod clamped between two rigid walls when the temperature is increased

The usual approach to calculate stress is to equate thermal expansion in the unclamped condition to the magnitude of contraction caused by strain produced due to the walls. I have some questions about ...
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How do photons give atoms more heat energy?

this is a duplicate of this question but I came away not understanding the answer, even after reading the links. so my question is: how does light increase the heat energy of an atom? eg. if you ...
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what has the higher entropy: tap water or hot coffee?

I can't get this simple question out of my head. Does tap water have higher entropy since its temperature is almost in equilibrium with the surrounding? Or does hot coffee have higher entropy since ...
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Math notation for heating object

An object with mass $m$ and heat capacity $c_{p}$ is exposed to heating $P_{th} $[kW] and thermal losses $\dot q$ [kW/°C]. The energy equation illustrating the process of heating it from $T_{max}$ to $...
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How much does temperature affect the time of sunrise?

Please forgive me if this is a dumb question, or if my understanding of basic physics is wrong. Please feel free to correct me. As I understand it, if the Earth didn't have any atmosphere, then the ...
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Cooling photons to a solid state

Can we cool photons so the stop moving completely? So they can behave like particles in a solid.
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Bring energy into mixing hot and cold taps

Are you able to bring energy into your equation? I like to know if there is a way to calculate the required energy necessary to obtain a given temperature and flow at the outlet of the mixer when hot ...
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What does the area under the curve of a temperature-time graph represent?

I’m trying to calculate the total heat produced by a system over a period of time and I’ve gotten a regression line of y= log x to represent the best produced by the system. To calculate the total ...
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Understanding Ising Model in Statistical Mechanics

A section on the Ising model in the text "Introduction to modern statistical mechanics" by Chandler states the following: "We consider a system of $N$ spins arranged on a lattice. In the ...
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Magnetic Field Strength Measurement at Extreme Temperatures

I have just been given a project at work and we are magnetically stress testing DUTs at extreme temperatures going from -40 Degrees Celsius to 200 Degrees Celsius. I need to come up with a way that we ...
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Is there any change in temperature due to special relativity? [duplicate]

Say I am travelling in a spaceship very close to the speed of light. Would there be any change in temperature in the spaceship relative to outside the spaceship? Please explain in detail.
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Water mixture at different temperatures

Let's say that we mix homegeneously and instantly cold water at $t^\circ $ C and hot water at $T^\circ$ C (like in a water tap) in ratio $p:1$. My question is the following: What is the instant ...
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1answer
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Does the cold affect electrical conduction?

Disclaimer: I'm not experienced in many phyiscal nor electrical terms and I have no idea where to ask this question elsewhere. I'd be open for a move request if needed. Today when using public ...
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Is the *measured* temperature inside a hollow black body the same if we place a thermometer inside it or let it make contact with the body itself?

Imagine the inside of a black body shell with non-zero thickness. Inside the shell, there is photon gas produced by the shell [at a temperature much higher than zero, say $1000(K)$]. Is there is a ...
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Time for black body to cool to a given temperature

I'm trying to figure out the time required for a blackbody to cool assuming it only looses heat via radiation. I can estimate the mass, specific heat, surface area, emissivity, initial temperature, ...
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Maximum achievable mechanical work when heating water

I am doing a question about finding maximum achievable mechanical work when 1L of liquid water is heated from T₁ to T₂ at atmospheric pressure. The solution is $$W = \int_{T_1}^{T_2} \frac{T - T_1}{T} ...
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How is quantum mechanics consistent with statistical mechanics?

Let's say we have an harmonic oscillator (at Temperature $T$) in a superposition of state 1 and 2: $$\Psi = \frac{\phi_1+\phi_2}{\sqrt{2}}$$ where each $\phi_i$ has energy $E_i \, .$ The probability ...
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Calculate temperature decrease of an evaporating droplet

I have a small droplet of Cyclohexane which evaporates at room temperature and ambient pressure. I measured the volume at two different times ($\Delta V=1.5\times10^{-10}$ m$^3$). I would like to ...