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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Major loss of heat in solid body full contact heat transfer

I have the following piece of laboratory equipment: magnetic stirrer with hot plate. I set it to 60 degrees Centigrade and put this metal bowl on it: After a bit I measured the temperature of the ...
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1 answer
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Relationship between viscosity and temperature

I'm a high school student, and I am interested in fluid viscosity. I was doing an experiment, and I got some data points. Following are some of them. Here,x1 is for temperature(in kelvin), and x2 is a ...
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How can the Gibbs free energy equation be at constant temperature and pressure?

I have read that the equation $\Delta G = \Delta H-T\Delta S$ is valid only at constant temperature and pressure. However, $\Delta H=0$ in an isothermal process which would give $\Delta G = -T\Delta S$...
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Understanding temperature drop within throttling processes

I am studying a particular throttling process (https://en.m.wikipedia.org/wiki/Isenthalpic_process, https://en.m.wikipedia.org/wiki/Joule%E2%80%93Thomson_effect): cryogenic flow going through an ...
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How can the temperature of the surroundings be constant during a reversible thermodynamic process?

I am having trouble reconciling the following statements I have recently learned about thermodynamics: The temperature of the surroundings is taken to be constant (with only infinitesimal changes) ...
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1 answer
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Temperature rising of solar collector

I would like to calculate the heating of a polyethylene solar collector as a result of the sun's radiation. the collectors are uncovered collectors. Suppose I have a certain intensity $I$ of solar ...
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3 answers
557 views

Final temperature of a mixture of water and ice in a copper container

Lets say I have ice of mass $m_i$ and initial temperature $T_i$ and specific heat $s_i$ . And I have water of mass $m_w$ and initial temperature $T_w$ and specific heat $s_w$ . I have put both this ...
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Could a window mounted wet cloth sheet chill a room?

Assuming there is a light wind, that construction is partly shaded and a constant water pouring and evaporation of the material is occurring due to the breeze.
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1 answer
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How hot can steam be?

The title really says it all. How hot can steam (gaseous form of water) be before it ceases to be steam. I'm assuming that at some point the molecular bonds will give way, though I might of course be ...
2 votes
4 answers
336 views

Is high temperature **required** for nuclear fusion?

Tl;dr: Can fusion be achieved only by speeding up particles to high enough speeds to smash into each other? I know that it is necessary for protons, or any oppositely-charged particles for that ...
1 vote
1 answer
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Optimal temperature for Mpemba Effect

Is there an optimal temperature for the Mpemba Effect? If so, what is it? If a specific example is needed: There is a 100 milliliter sphere of water floating in air at -10 °C. At what initial ...
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The derivation of the Planck distribution

I am trying to understand the derivation of the Planck distribution and black body radiation. In the Wikipedia derivation of the Planck distribution, the photons confined within a cubic box, are ...
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1 answer
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Why are higher frequencies amplified less by filling a bottle with warmer water instead of colder water?

Out of curiosity I was trying to figure out what makes the sound of hot water versus cold water filling a bottle different, but I'm unable to find any explanation as to why such differences occur. ...
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Deriving Andrade's equation

$$\eta=a\exp\frac{B}{RT}$$I'm a high school student, interested in fluid dynamics. I was studying the relationship between viscosity and temperature, and I understood that when liquid heats up, its ...
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BTZ black hole and thermal $AdS_3$

Why Euclidean $BTZ$ black hole at temperature $T$ is equivalent to thermal $AdS_3$ at temperature $1/T$? I'm not really familiar with those objects, but I have used the modular transformation $\tau_{...
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Why does the speed of sound in water not increase proportionately with temperature? [duplicate]

I was just wondering, as per this graph (https://www.engineeringtoolbox.com/sound-speed-water-d_598.html) why the speed of sound in water does not increase proportionately with temperature. Instead ...
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Shockley diode equation - temperature influence

when looking at Shockley's ideal diode equation I wonder what "meaning" the temperature has in there? If I assume $$I(T) = I_0 \left[\exp \left( \frac{U}{k_BT/q}\right)-1 \right]$$ and vary ...
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Galileo thermometer [closed]

Is it true that the clear fluid in the tube is ethanol? And that the weights attached to the glass bubbles are gold?
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Determining the Boyle temperature (non-numerical) [closed]

I have been given the following equation of state (in relation to ideal gas laws): $$PV_{m} = RT \left( \ 1+\frac{8}{57}\left(\frac{P}{P_{c}}\right)\left(\frac{T}{T_{c}}\right)\left[1-4\left(\frac{T_{...
1 vote
2 answers
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What's happening at a molecular level to the resistance when the temperature of salt water is increased?

What's happening to the electrical resistance at a molecular level when the temperature of a water with a bit of salt is increased? I noticed that the resistance decreases but in metals it is totally ...
1 vote
4 answers
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Why water's temperature is less than air?

I measured the temperature of water and found that it's less than room temperature. I think evaporation is the main reason of it. Are there any reason except evaporation for the less temperature of ...
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2 answers
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Why are my altitude calculations off? (hypsometric formula)

I'm trying to accurately measure height data during the bench press exercise. I'm using a barometer and a thermometer sensor attached to the bar to capture the data. To calculate altitude, I've been ...
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1 answer
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Moments of physical qualities other than density

If I have some genuine physical object $\Omega$ (that I can describe mathematically) and want to find its center of mass, I can compute its moments to get each coordinate of that center; for example, ...
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1 answer
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Calculating time it takes to heat water in a microwave and the steam to evaporate

I am stuck on a question in my thermodynamics class. We have studied topics such as heat $Q$, entropy $S$, enthalpie $H$, etc. Bob puts a glass containing 500 grams of water in the microwave. Before ...
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2 answers
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What causes the distribution of energy among molecules?

If every molecule were to start of with the same kinetic energy would it become a distribution of energy like the boltzman distribution and if so why? Is it due to inelastic collisions?
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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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2 answers
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Perpetual motion of zeroth kind?

Perpetual motions are classified by which law it breaks: Perpetual motion of first kind breaks the first law of TD. It generates energy from nowhere. Perpetual motion of second kind breaks the second ...
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Does specific heat capacity of an ideal gas depend on static or total temperature?

The specific heat capacity $c_p = c_p(T)$ (J/kg/K) of an ideal gas depends on its temperature. However, the gas has a static temperature ($T_s$) and a total temperature ($T_i$). As we have for the &...
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How to derive $ TV^{1-\gamma}$? I get $ \frac{T}{V^{1-\gamma}}$ [closed]

For an adiabatic process we have $dQ=0$, thus the first law gives: \begin{align} \mathrm{d}E &= \mathrm{d}W, \\ nC_V \mathrm{d}T &= - P\mathrm{d}V = - \frac{nRT}{V} \mathrm{d}V, \\ \frac{\...
3 votes
1 answer
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Pressure in a gas as it becomes a plasma

Let's say you have 1 mole of hydrogen, and you heat it to the point that the H-H bond breaks and you get free hydrogen atoms, and then fully ionized hydrogen ions + electrons. When H2 becomes 2H (...
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What temperature does the average stainless steel kettle left on a stovetop reach?

I was trying to find out the time it'd take for a liter of water in a kettle to boil on a normal stovetop (avg temp:400°C) but I got stuck on heat energy of the kettle absorbed from the stovetop by ...
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2 answers
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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 ...
7 votes
1 answer
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Interpretation of temperature in General Relativity

I am reading the historical article by Hawking and Page. Their exposition of the Hawking-Page transition differentiates the notion of temperature in both AdS and SAdS spacetimes, as both of these ...
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1 answer
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Effect of temperature on specific weight

How much of an impact has a temperature difference when the specific weight of an object in water is measured, e.g. the weight of a mussel in seawater. Would the two scenarios yield the same specific ...
4 votes
2 answers
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Calculating new temperature of an object when air temperature changes

I'm trying to calculate the new temperature of an object when the air temperature around it changes, given a period of time. Basically I get periodic readings from an air temperature sensor in a ...
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3 answers
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Calculate Heat capacity with temperature and total energy

I have a molecular Dynamics simulation and want to calculate the heat capacity with constant volume of my material. As output parameters I can get temperature, potential energy, kinetic energy, total ...
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1 answer
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On writing the entropy of a system as function of other parameters; Reif exercise 5.14

I am having trouble understanding the proposed solution for a problem taken from "Fundamentals of Statistical And Thermal Physics" by F. Reif. The problem is taken from the chapter 5 - ...
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5 answers
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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 ...
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1 answer
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Does standard enthalpy of reaction assume a constant temperature?

I've attached a question and a solution from Reif's textbook. It seems to me that there must be the assumption of constant temperature, and I'm hoping someone can confirm. I can express the enthalpy ...
3 votes
2 answers
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What is an intuitive explanation for $T = \mathrm{const}$ when $\Omega(E) = e^E$?

Temperature is related to number of microstates as follows: $$ \frac{1}{k_{\mathrm{B}}T} = \frac{\mathrm{d}\ln{\Omega(E)}}{\mathrm{d}E} \ . $$ Hence, if $\Omega(E) = e^E$, then $T = \mathrm{const}$. ...
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What is temperature: function of energy or the value of this function in thermal equilibrium?

As far as I remember, many textbooks on statistical physics introduce temperature as a condition of equilibrium of a composite thermodynamic system. E.g., if the system consists of two parts with ...
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6 answers
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Is sand in a vacuum a good thermal insulator?

My reason for thinking that sand in a vacuum would be a good insulator is that heat cannot be conducted in a vacuum, and the area of contact between adjacent grains of sand is very small, which means ...
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Convert units of Empirical Orthogonal Function (EOF) for sea surface temperature data

I have a dataset of daily averaged sea surface temperatures for an entire year. I wish to use an empirical orthogonal function to find the dominant patterns within the data. Consider that my ...
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1 answer
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Curie point temperature and effect on induced magnetization

My question is related to how the induced magnetization of a material behaves above the Curie Point Temperature. My understanding was always that the thermoremanent component of magnetisation is lost ...
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Maximum temperature of plasma according to $pT$ diagram

When I look at the graph, I can find maximum temperature of plasma (roughly 1eV at 10kPa). But you can get a lot hotter with plasma. Please, where is the mistake? See: or See: https://www....
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Does the response of a fiber-optic sensor to strain increase as temperature increases?

Fiber-optic sensors etched with Bragg diffraction gratings are used as temperature sensors in many applications. They are also used to measure strain. As the strain or temperature increase, the peak ...
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How does the literature resolve this contradiction about the sudden approximation? [closed]

Background Consider the measurement. The measurement maps an arbitrary energy eigenstate $|E_i \rangle$ to $| \phi \rangle$: $$|E_i \rangle \to | \phi \rangle$$ with a probability of this outcome is $...
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Degrees of Freedom of water and $\rm CO_2$ at high temperatures

How do I calculate the degrees of freedom for $\rm CO_2$ and water at high temperatures? I'm confused because I know $\rm CO_2$ is linear while $\rm H_2O$ is nonlinear, and am wondering how this would ...
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Freezing at high temperature

The temperature of the atmosphere at a high altitude is around 500° C. Yet an animal there would freeze to death and not boil. Explain. I know that on the surface of the moon a pot of liquid will ...
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Can we use negative temperature for nuclear fusion?

I have read in books and articles saying negative temperatures are higher than any possible positive temperature. So this temperature would also be greater than 100 million C. Can't we use it for ...

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