The Stack Overflow podcast is back! Listen to an interview with our new CEO.

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.

Filter by
Sorted by
Tagged with
0
votes
1answer
46 views

Why is it possible to raise the temperature of water over the boiling point?

For example, if we take water at a constant pressure and increase the temperature fast enough over the boiling point, the water will not boil. Why does it happens?
0
votes
1answer
9 views

Resistance and temperature mathematical relationship of a thermistor

When I did an experiment measuring the Resistance of a thermistor as I increase or decrease the temperature, when I plot the resistance (y - axis) against temperature (x-axis), I get an exponential ...
0
votes
2answers
53 views

Applying the Clausius Inequality to Three Systems

Suppose we have three systems made up of the same amount of the same substance, $S_1, S_2$ and $S_3$. They start with temperatures $T_1$, $T_2$, $T_3$ such that $T_1>T_2>T_3$. We can place the ...
0
votes
2answers
90 views

Addition of Temperature Units [duplicate]

I would like to know how does the addition of temperatures works. In school, we have been taught that we should convert degrees Celsius to Kelvin unit first and then the sum will be converted back to ...
0
votes
2answers
102 views

What is heavier, water or ice?

I was reading this link and I never saw a definite answer. One would think if you have 1000 pounds of water, and you froze it and weight it you would still have the same 1000 pounds of water when ...
-1
votes
2answers
25 views

Calculate power of a solar heater [on hold]

This week-end I build a small solar heater of 1.2meter by 1.2meter. Basically a closed box with the back painted in black and front cover with a transparent plastic. I trying to know the rough ...
1
vote
0answers
16 views

When Measuring Altitude for a High Altitude Balloon does Temperature Matter?

When I look at the High Altitude Ballon results from people online that have launched DIY balloons (that have posted their data) I can see that their claimed top altitude (based on the pressure they ...
1
vote
3answers
57 views

Does temperature coefficient of resistance depend on geometry?

By temperature coefficient of resistance of a material about a reference point $T_0$, I mean $${1\over R(T_0)} \left.{dR\over dT}\right|_{T_0}.$$ All the sources (that I’ve seen) that quote this ...
0
votes
0answers
19 views

What is the temperature at which water will boil at an altitude where pressure drops by 10%? [closed]

If there is a 10% decrease in the atmospheric pressure at a hill compared to the pressure at sea level, then the change in the boiling point of water is_____ °C. (Take latent heat of vaporisation of ...
0
votes
1answer
61 views

Is the kinetic theory of gas relative in nature

In kinetic theory of gas the foremost assumption is that the temperature of an object is due to the kinetic energy of the atoms/molecules contained in it. But as we know that kinetic energy is a ...
1
vote
0answers
23 views

Order of Magnitude of Cosmic Microwave Background Anisotropies

How does the statement about the anisotropies being of the order of $\frac{\Delta T}{T} \approx 10^-5$ which is often made in the literature (see, e.g. Description of CMB Anisotropies by Scott and ...
3
votes
0answers
70 views

Negative temperature of the de-Sitter horizon?

I'm considering the $4D$ de-Sitter spacetime, in static coordinates (I'm using $c = 1$ and $k_{\text{B}} = 1$): \begin{equation}\tag{1} ds^2 = (1 - \frac{\Lambda}{3} \, r^2) \, dt^2 - \frac{1}{1 - \...
5
votes
2answers
180 views

Derivation of temperature / entropy relation from statistical mechanics

I am trying to prove that \begin{equation} \frac{1}{T} := k_B\beta = \frac{\partial S}{\partial E}. \end{equation} I have that \begin{equation} E := \sum p_i E_i, \end{equation} the Gibbs entropy \...
12
votes
3answers
2k views

How much do sea levels rise due to thermal expansion?

I was reading an article by the Smithsonian Institute about the rising sea levels. In it, they mention how warmer water expands more, thus it helps to raise the average sea level. This makes perfect ...
1
vote
1answer
21 views

Does a maximum thermometer assume a room temperature?

Consider a liquid-in-gas maximum thermometer. That is usually conventional thermometer designed for measuring body temperature. Wikipedia says: One special kind of mercury-in-glass thermometer, ...
6
votes
1answer
123 views

Trouble with conceptualizing the “temperature” of a deck of cards

Entropy is quite often introduced with the help of a deck of cards. Because there are so many cards, and thus an enormous number of microstates (orderings of the cards), if we assume equipartition of "...
0
votes
1answer
86 views

Calculation of final temperature [closed]

what would be the final temperature of any body with the change in the ambient temperature? A Body temperature was recorded at 27.2°C ambient temperature is 60.2°C Final temperature of body is 60....
1
vote
0answers
57 views

What temperature increase results from the current 410 PPM spike in $CO_2$?

I have had three semesters of college statistics as part of my BSBA degree. From what I recall from regression analysis the graph seems to show a very high coefficient of determination between CO2 and ...
0
votes
1answer
24 views

Confusion about internal energy and temperature during a phase change

During a phase change, internal energy of a system will change because energy must be added or subtracted (depending on "direction" of change) from the system in the form of latent heat. However, the ...
3
votes
1answer
49 views

Do particles splitting decrease temperature?

I was thinking about temperature, and had a thought. Temperature is proportional to the average temperature per particle. If you split a particle, you have twice as many particles but only the same ...
0
votes
0answers
12 views

Gradient of pressure - density and temperature dependence

How it related gradient of the pressure to temperature and density of the gas? When temperature is hight and density low why gradient of the gas (or repulsive electromagnetic forses between atoms and ...
0
votes
1answer
73 views

Why is the triple point of water defined as 0.01 degrees Celsius and not 0?

This was stated in my thermo dynamics lecture today and I tried to ask my lecturer why it was not just defined as 0 since 0.01 seems weirdly specific. She was mentioning something about the order in ...
1
vote
0answers
24 views

Reaching 0 K in a “Finite number of steps”

Let me preface this by saying that I don't really like the third law of thermodynamics very much. Its not that I believe its not true, its just that it feels non rigorous, all its different ...
1
vote
1answer
37 views

General conduction equation for 1D using Fourier's law

A product is coming out of a single hole die plate at a rate of 2g/s from a temperature of 98C to 10C. I want to know how long it takes to cool below 43C. The product is a cylindrical tube or radius ...
0
votes
1answer
32 views

Is it possible to derive at what time during a cook process a certain temperature was reached?

I work at a frozen foods manufacturer, and we have a particular lot of product that is currently being held pending inspection, due to new regulatory requirements. To keep it concise, we need to ...
0
votes
1answer
51 views

Is the temperature of a fluid zero if the particles have no random motion?

In my course on mathematical fluid dynamics, the temperature is defined by the relation $$\frac{3}{2}k_BT=\frac{1}{N}\frac{1}{2}\sum_{k=1}^{N}m_k|\vec{v}_k-\vec{v}|^2,$$ where $\vec{v_k}$ is the ...
1
vote
0answers
27 views

Principle of a pyrometer

How does a pyrometer work? Especially how do I ensure that the temperature of a single spot is measured (where the laser points at)? Here is a scheme of the structure but I guess it's not really ...
0
votes
0answers
15 views

Speed of sound in Aluminum given the debye temperature

I am trying to calculate the speed of sound in aluminum given the Debye temperature $\theta_D=428 \;\mathrm{K}$, the mass density of Al is $\rho = 2.7 \cdot 10^3 \;\mathrm{kg}\cdot \mathrm{m}^{-3}$, ...
2
votes
1answer
70 views

Why is the temperature of a black hole given by $T=E/2S$?

Naively, I would imagine that $$ T = \frac{E}{S} $$ However, for a black hole, $E=c^4 R / 2G$ and $S= A k c^3 / 4 G \hbar $, which yields $$ T = \frac{E}{2S} $$ Is there a simple explanation for the ...
0
votes
2answers
62 views

Is it possible for a radiant heat transfer to create higher temperature in the sink compared to the source?

Assume we concentrate the rays of the sun onto an object (in the vacuum of space) that has very low emissivity - The energy coming in is higher than the amount being emitted as radiation - hence it ...
0
votes
2answers
37 views

What is the real physical property behind the term “temperature” on macro-level?

Let's assume I have two ideal cubic solid bodies. I place them close to each other, so there is no gap between faces. For simplicity let it be in vacuum. And they will start to interact by exchanging ...
0
votes
0answers
40 views

Heisenberg uncertainty principle on bosons at absolute zero [duplicate]

Bosons obey Heisenberg's uncertainty principle but not Pauli's exclusion principle. In Bose-Einstein Condensation quantum effects are much more important and here we get a large number of particles ...
2
votes
1answer
63 views

Theoretical justification for the range of validity of the approximation $R(T)\approx R(T_0)[1+\alpha (T-T_0)]$

In the experiment for calibrating a platinum resistance thermometer, we are always approximating the resistance of the platinum thermometer by $$R(T) \approx R_0 (1+\alpha T),$$ taking the reference ...
0
votes
3answers
102 views

Boiling water on gas stove

Does boiling water really heats room faster than just gas stove? I know that is not true, but I need some more detailed explanation.
0
votes
0answers
31 views

Limits to natural convection in a non-infinite medium

I'm trying to understand the temperature profile of a fluid in an underground vertical pipe without flow. The fluid is subject to a boundary condition of the form: $$Q = h[T_e(z) - T],$$ where $Q$ ...
23
votes
5answers
7k views

Why do things cool down?

What I've heard from books and other materials is that heat is nothing but the sum of the movement of molecules. So, as you all know, one common myth breaker was "Unlike in movies, you don't get ...
2
votes
0answers
80 views

Which temperature transformation does QFT allow?

Background Taken from here Is temperature a Lorentz invariant in relativity?: Einstein himself, in a 1907 review (available in translation as Am. J. Phys. 45, 512 (1977), e.g. here), and ...
1
vote
1answer
35 views

Is there a Mass-Temperature relationship for main sequence stars?

When finding relationships between various properties of stars, I frequently find next to nothing on the Mass-Temperature relationship. I, of course, see the Mass-Luminosity and the Luminosity-...
0
votes
0answers
39 views

Experimental Calculating Optical Lens for Temperature IR Sensor. (heat emitting 20x20cm object in a distance from 13cm)

I need to calculate online heating temperature of thermoplastic by the MLX90614 IR Sensor shown blow: used in one Vacuum former device. As you can see i need to calculate the thermal plastic ...
1
vote
2answers
43 views

Does metal thickness change with rise in temperature?

When a metal pipe or metal cylinder is heated uniformly in furness, inner and and outer diameter of cylinder increase and its length also increase but does thickness of the cylinder change with change ...
0
votes
0answers
29 views

Double Sommerfeld Expansion

Consider the Fermi-Dirac expansion for an arbitrary function $f(\epsilon)$: $I(f)=\int_0^\infty d\epsilon\frac{f(\epsilon)}{e^{\beta(\epsilon-\mu)}+1}$ The large $\beta$ expansion of this quantity ...
0
votes
1answer
91 views

How is 0th law of thermodynamics possible?

If a body of gas A (say at $25\ ^\circ \rm C$) is brought in contact with another body of gas B (say at $10\ ^\circ \rm C$), then B absorbs heat from A until they both reach $17.5\ ^\circ \rm C$ and ...
4
votes
1answer
61 views

Why doesn't mercury flow in the thermometer?

Nowadays digital thermometers are used, but in the past mercury based thermometers were used. From my experience the mercury does not flow in the thermometer tube. Mercury is a liquid, so it must have ...
0
votes
0answers
16 views

Evaporation rate vs. volume relative humidity

I have a certain volume (V, in cubic centimeters) of air with a given temperature (Ta in Celsius) and relative humidity (RH %). Inside it I have a glass of water with a free surface with the same Ta. ...
0
votes
1answer
23 views

Equilibrium temperature of a black body when the volume of the black body is changed

If a black-body is at an equilibrium temperature T of a certain volume. If we increase size of blackbody does the equilibrium temperature of the blackbody will change?
0
votes
1answer
78 views

Formulas related to “Cooling a cup of coffee with help of a spoon” [closed]

I was recently going through some of the top voted questions on the thermodynamics tab. And, I came across Cooling a cup of coffee with help of a spoon. I found this question really interesting. In ...
0
votes
1answer
42 views

Why is the secondary inlet temperature in a Pressurized Water Reactor (PWR) so high?

According to this link (along with many other PWR papers), the inlet temperature of the secondary into the steam generator is around 450-500K, with a pressure of 5-8MPA. How does the temperature of ...
-1
votes
1answer
87 views

How does the Sun warm a person? Is it convection, Conduction or Radiation? [closed]

I know that heat transfer can be conduction, radiation or convection, but I don't know which one it is.
-1
votes
2answers
59 views

Nuclear-powered Ramjet + criticality

I came across this Wikipedia entry about Project Pluto; a nuclear-powered ramjet that the U.S. was developing back in the day. https://en.wikipedia.org/wiki/Project_Pluto This missile would have ...
7
votes
3answers
1k views

How do we tell which part of kinetic energy gives rise to temperature?

I know that macroscopic temperature is a measure of kinetic energy of particles at very low scales (let's call it microscopic kinetic energy). But how can we derive which part of this microscopic ...