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
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2answers
23 views
How would a change in ambient temp affect a radiator?
I'm curious if you have a radiator or say a block of metal (lets say it's copper since it has the highest thermal conductivity) and on one side is a processor producing heat.
At idle the processor ...
2
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3answers
119 views
What is the general statistical definition of temperature?
Temperature in an isolated system is defined as:
$$\frac{1}{T} = -\frac{\partial{S(E,V,N)}}{\partial{E}} $$
But I wonder how one can generalize this to a random system.
Or for instance to a point in ...
0
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2answers
24 views
High and low pressure area and raining
In the high-pressure area it is mostly likely that there is sun. In low pressure area it is mostly likely that rain will occur.
Because of the law that ...
2
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2answers
113 views
Why is the temperature zero in the ground state?
This is probably a simple question: I see this claims in many books, but I can't figure a reason why this is true.
So my question is why this claim is true:
"If we know that the system is in the ...
1
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1answer
74 views
Does brown but transparent swimming pool water heat significantly faster than western style highly chlorinated pools?
Eastern European swimming pools are often brown tinted water. i was told it was the color of the chemical to keep the pools clean, but who knows. These pools did not smell unsanitary and may have even ...
2
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2answers
57 views
What is the derivation for the exponential energy relation and where does it apply?
Very often when people state a relaxation time $\tau_\text{kin-kin}, \tau_\text{rot-kin}$,, etc. they think of a context where the energy relaxation goes as $\propto\text e^{-t/\tau}$. Related is an ...
1
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1answer
25 views
Speed of air through valve
Right now I'm working on a hot air balloon in Physics formulas. At the moment it's flying up like it should, but once it is at a certain height we want it to go back down.
After some research about ...
1
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0answers
28 views
Can I maintain a constant relative humidity using saturated salt solution, at greater than atmospheric pressure? [migrated]
At atmospheric pressure and between temperatures of $\sim 0$ to $100^\circ C$, well known relationships between established humidity and given saturated salt solution are available. I.e. ASTM E104 ...
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0answers
22 views
Removing seasonal and non-seasonal oscillations with least-square method [closed]
I was trying to find help online, but with no luck :( Hoping you will help me!
I have data containing sea temperature with depth. With data I need to remove seasonal and non-seasonal oscillations by ...
4
votes
1answer
41 views
Reflectivity of a glowing-hot metal surface
When a polished piece of metal (or steel in particular) is heated to incandescence, how do its reflective properties change?
Given a mirror-like surface, would the object temporarily cease to act ...
0
votes
0answers
15 views
What is the effect of an increase in pressure on latent heat of vaporization?
What is latent heat of vaporization ($L_v$) in the first place? Wikipedia seems to indicate that it is the energy used in overcoming intermolecular interactions, without taking into account at all any ...
1
vote
1answer
67 views
Ginzburg-Landau model for superconductivity
Could someone kindly elaborate more on the Simple Interpretation section from this Wikipedia Article? I refer to the part on the natures of $\alpha , \beta$. Why can one assume that ...
2
votes
1answer
41 views
Temperature of a small system
What is wrong if I define temperature of a small system (I mean, a system which has not a large number of particles) by
$$1/T = dS/dE$$
?
1
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0answers
53 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 ...
0
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1answer
47 views
Negative temperature and Absolute hot
This video explains that heat at negative temperatures flows from the negative object to the normal object. If the temperature of the normal object is absolute hot, what happens with the heat? The ...
4
votes
1answer
32 views
Is there a naturally occuring sound pressure level reference?
There are lots of devices that purport to measure the absolute value of sound pressure levels. Here is an example, here's another, there's also this iPhone App. Putting such devices side-by-side in ...
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votes
1answer
44 views
Heisenberg's uncertainty and $0 K$ temperature
when a body is subjected to $0 K$ temperature, it becomes rigid. hence if we see in terms of quantum the lattice vibration decreases, resulting in no change in the direction of the Random velocity, ...
0
votes
2answers
110 views
How can anything be hotter than the Sun?
I've heard that if a space shuttle enters the atmosphere from a bad angle its surface will become so hot that it will be hotter than the surface of the Sun.
How can that be? It seems to an uneducated ...
0
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0answers
30 views
Negative temperature [duplicate]
How can we prove that if a negative-temperature system is in contact with a positive-temperature system, then the heat flow from the first to the second (and finally, the temperature of the second ...
0
votes
1answer
64 views
How to understand the thermal radiation?
I am studying the thermal radiation (Stefan–Boltzmann law) by myself
$$P = \epsilon \sigma A T^4$$
here $\epsilon$ is the emissivity, $\sigma$ is Stefan-Boltzmann constant, $A$ is the surface area ...
1
vote
3answers
132 views
Integrating factor $1/T$ in 2nd Law of Thermodynamics
How would you prove that $1/T$ is the most suitable integrating factor to transform $\delta Q$ to an exact differential in the second law of thermodynamics:
$$dS = \frac{\delta Q}{T}$$
Where $dS$ is ...
1
vote
1answer
43 views
Is it physically meaningful to talk about the 'total temperature' of an object?
If I had a semi infinite, 1-D object and a finite 1-D object, both heated at the same constant rate at one end each for the same time period and both begin at the same initial temperature, is it ...
0
votes
1answer
45 views
Electromagnetic field to cool a substance?
I saw somewhere that an electromagnetic field would cause a substance to let off thermal energy, ultimately resulting in the substance to cool really quickly.
If this is possible, does the strength ...
0
votes
2answers
91 views
How temperature gradient is a vector?
Everyone knows Temperature gradient is a vector quantity having direction from cold to hot.My confusion: why is temperature gradient vector if its direction is always fixed (as in the case of ...
1
vote
2answers
28 views
Heating and Recooling of an Object
Consider a piece of metal of length $L$ and linear thermal expansion coefficient $\alpha$. We eat the metal $\Delta T$ degrees, causing the metal to increase to length
$$ L' = L + L \alpha \Delta T$$
...
1
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1answer
92 views
Does gravity affects temperature reading of a mercury thermometer?
I remember when I was in primary school, the science teacher put me in charge of a mercury thermometer. I do not quite understand the mechanics behind except that mercury expands when it is hot and ...
16
votes
6answers
1k views
Why isn't temperature measured in Joules?
If we set the Boltzmann constant to $1$, then entropy would just be $\ln \Omega$, temperature would be measured in $\text{joules}$ ($\,\text{J}\,$), and average kinetic energy would be an integer ...
4
votes
2answers
83 views
How hot would space feel?
I read that the temperature of the space around the earth can vary greatly depending on whether or not it is in direct sunlight. Space, however, is not very dense, so I imagine that heat would not ...
1
vote
1answer
57 views
How long does it take a warm object to cool in air?
This is a work-related question. A warm steel torus of a given diameter & thickness is left in a room held at a controlled temperature, how long does it take to reach equilibrium? Assume the air ...
3
votes
2answers
174 views
What's the avarage temperature of the Universe?
I'm sorry if this was asked before but with all the stars and dark matter and all the other stuff, curently in the Universe, what's the avarage temperature of the Universe? Is it like extremely high ...
36
votes
5answers
4k views
How long can you survive 1 million degrees?
I asked my Dad this once when I was about 14, and he said that no matter how short the amount of time you were exposed to such a great temperature, you would surely die. The conversation went ...
0
votes
0answers
50 views
Temperature of an Object in Space [closed]
Rotating cylinder in space
Hi all
I've been having problems trying to calculate the temperature of an object in space, and was hoping I could get some help. Say we have a cylinder in space rotating ...
1
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0answers
43 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 ...
2
votes
1answer
135 views
Does an object's color change its rate of cooling?
The motivation for this question comes directly from this thread. The proposition is that the color of something changes how fast it cools (note: specifically the rate of cooling, not taking into ...
1
vote
1answer
126 views
Absolute zero and Heisenberg uncertainty principle
I got to read Feynman vol I and there was written that at absolute zero, molecular motion doesn't cease at all, because if so happens, we will be able to make precise determination of position and ...
2
votes
2answers
133 views
Why the temperature is getting lower when the universe is expanding
As we know, if an ideal gas expands in vacuum, as its energy is unchanged, the temperature remains the same. An ideal gas's energy does not depend on volume. In general, the energy is $kT$ times the ...
4
votes
1answer
98 views
Does the Kelvin have a rigorous definition?
From Wikipedia:
The kelvin is defined as the fraction 1⁄273.16 of the thermodynamic temperature of the triple point of water.
That presupposes that we can take a fraction of temperature.
Now, ...
3
votes
2answers
141 views
What's the basic difference between heat and temperature?
Temperature is usually seen as a calibrated representation of heat but what about latent heat?
Eg. Ice and water have different amounts of heat at 0 degree c.
4
votes
2answers
115 views
Room temperature and fan orientation
So I'm in a tiny dorm room and I normally point my fan blowing outside the window to cool my room off. I've been in some debates on blowing air out or in is more effective, so I'm hoping to get some ...
1
vote
1answer
99 views
Does increasing the density of a solution decrease the rate of temperature change?
I did an experiment to compare whether salt water (5% concentration of salt) or fresh water of the same volume took longer to heat up to a certain temperature. We found that salt water took longer to ...
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votes
1answer
57 views
Predict final temperature by taking temperature samples?
Is it possible to predict what the final temperature will be by taking temperature samples. For example, an object is 0ºC and moved to a room above 0ºC. I'm taking temperature of the object using a ...
0
votes
3answers
198 views
Is rate of temperature change constant?
Is the rate of change in temperature for an object constant? For example, from 0ºC to 25ºC, or from 25ºC to -10ºC? Does it take the same amount of time to increase temperature from 1º to 2º as 24º to ...
3
votes
2answers
176 views
Ideal gas concentration under temperature gradient
I'm trying to calculate the concentration of an ideal gas in an adiabatic container as a function of position where the top and bottom plates of the container are fixed at temperatures $T_1$ and ...
9
votes
3answers
201 views
Does sound propagate further in freezing weather?
A few days ago I went for a walk in the evening. We're having winter with a little snow and freezing temperatures. We're in a quiet, shallow valley with a train station about 1km from us. I heard a ...
3
votes
3answers
122 views
Temperature in space
Temperature is a measure of kinetic energy transferred to particles, henceforth, space being vacuum, temperature cannot be measured.
But then, there is cosmic background radiation. It is the leftover ...
2
votes
1answer
103 views
Does electric potential have a temperature?
When I took my first thermo class a tucked away chapter introduced Exergy in terms of electrical energy, meaning that the amount of electrical energy you could get from something is functionally its ...
3
votes
2answers
135 views
With ideal gases, varying quantity of moles, and having a constant volume how do temperature and pressure behave?
I'm trying to build a simulation of gases so I ended-up trying to use law of ideal gases ($PV = nRT$).
In my scenario:
volume is constant ($V=1\rm{m}^3$);
a known quantity of moles are being added ...
3
votes
1answer
129 views
Why aren't two systems in thermal equilibrium the same as one system?
I am reading Molecular Driving Forces, 2nd ed., by Dill & Bromberg.
On page 53, example 3.9, we consider why energy exchanges between two systems from the point of view of the 2nd law.
We ...
0
votes
1answer
151 views
How to simulate temperature change of oven?
I am trying to write a software, which will model the oven temperature change when turning on/off. The data I can get is graph, by taking temperature reading each second from T0 time up to some ...
2
votes
0answers
56 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 ...
