The thermal-conductivity tag has no wiki summary.
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6answers
874 views
Does an empty refrigerator require more power to stay cold than a full one?
Given that everything else is equal (model of fridge, temperature settings, external temperature, altitude), over a given duration of having the door closed, does it require more electricity to cool ...
8
votes
4answers
775 views
What happens when you heat vodka in a microwave?
Since ethanol has a lower dielectric constant than water would the water heat up and boil before the ethanol? Would the water transfer heat to the ethanol and, since ethanol has a lower boiling point, ...
6
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2answers
149 views
When should I take wine out of the fridge - transient heat transfer problem
I am hosting a dinner tonight for which I'll be serving white wine (Riesling to be more specific). Generally white wine is best served chilled (not COLD!) at around ...
5
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3answers
2k views
Are specific heat and thermal conductivity related?
Are there any logical relationship between specific heat capacity and thermal conductivity ?
I was wondering about this when I was reading an article on whether to choose cast iron or aluminium ...
4
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1answer
60 views
Thermal conductivity affected by electrical current
Does anyone know of any materials whereby the thermal conductivity can be changed by passing an electrical current through the material?
4
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0answers
132 views
How do I measure the temperature of a tiny water droplet?
How do I accurately (+/- 0.1 degrees Celsius or better) measure the temperature of a small (5 to 50 microliter) water droplet without noticeably affecting its temperature?
The mass of a thermistor or ...
3
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4answers
523 views
Why water inside a vessel placed in a body of boiling water does not boil?
Imagine a plastic sac filled with water placed in a pan of boiling water. I wonder why the water inside the sac does not boil. The temperature of the water inside the sac should be the same as that of ...
3
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4answers
378 views
why does a larger thermal conductivity provide a smaller temperature gradient?
I was thinking about Fourier's Law in heat transfer today and for some reason I am just not understanding the relationships it gives us. Fourier's tells us that if the heat transfer rate is kept ...
3
votes
1answer
171 views
What is the time correlation function in the Green-Kubo formulation of ionic current?
I am reading a paper, and I came across the Green-Kubo formulation, where the conductivity $\sigma$ of charged particles is related to the time correlation function of the $z$-component of the ...
3
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1answer
780 views
Why is the lid of the cookware kept on induction cooker not hot?
Induction cookware cooks food by inducing an electro magnetic field in the ferro-magnetic cookware. Since iron offers a lot of resistance to the current, the current is converted into heat in the ...
3
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2answers
535 views
Why is oil a poor conductor of heat?
Why is oil a poor conductor of heat? Does it help in insulation?
3
votes
1answer
303 views
Why do some metal containers not conduct heat, while some do?
Some metal containers such as the Nissan Thermos ones, even if 100 C water is filled inside, the container is still cold to the touch on the outside. It won't be even warm:
At the same time, some ...
3
votes
2answers
399 views
How fast is heat transferred by conduction?
How fast is heat transferred by conduction? Is there some simple, but quantitative way that starts from some properties of the material (e.g. its thermal conductivity) and makes rough predictions, for ...
3
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2answers
211 views
What devices could be taken round dwellings to measure the thermal conductivities of buildings in situ?
Your lateral thinking and knowledge of lab kit could help us solve a tricky measuring problem in building-physics.
One of the problems we get in modelling the heat demands of buildings, is getting an ...
2
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3answers
120 views
Glass pipe cutting
I want to know how to quickly create the straightest possible breaks in glass pipes
I apologise if this is only borderline suitable for a physics forum - I just hope experts with a lot of experience ...
2
votes
1answer
85 views
What is the difference between contact-limited and space-charge-limited charge transport?
I am reading a paper ("Tunable Electrical Conductivity of Individual Graphene Oxide Sheets Reduced at 'Low' Temperatures," Jung, et al. Nano Lett. 2008, 8, 4283-4287) about electrical conductivity in ...
2
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1answer
642 views
Confused with stress, strain and linear thermal expansion
Four rods A, B, C, D of same length and material but of different
radii r, 2r , 3r and 4r respectively are held between two rigid
walls. The temperature of all rods is increased by same ...
2
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2answers
27 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
212 views
Putting a spoon in boiling tea brings the froth down. Why?
Two questions really:
1. Why does putting a spoon in boiling tea bring the froth down?
2. Also, the tip of spoon (outside tea) never heats up. I cannot imagine that normal air can have so much of a ...
2
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0answers
33 views
In a non-degenerate plasma, why are e-e collision negligible compared to e-ion for thermal conduction?
I'm trying to make some order of magnitude estimates of heat transfer in stars - to better understand 1) why conduction is said to be negligible (for non-degenerate matter) and 2) when convection ...
2
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1answer
133 views
Optical element is heated by laser: is it possible to get oscillating heat distribution?
Imagine that we have thin optical element, which is irradiated by laser. Laser heats element, so there is some heat distribution in element. There is a heat sink through upper and lower element faces ...
2
votes
3answers
367 views
Finite difference formulation of the heat equation with thermal conductivity in 1D
This may seem trivial, but I'm having some trouble deriving the finite difference form of the heat equation with a thermal conductivity function $a(x)$ depending on $x$:
$$\frac{\partial u(x, ...
1
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1answer
371 views
Do materials cool down in the vacuum of space?
Do materials cool down in the vacuum of space?
If yes, how does it really work?
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3answers
354 views
Maximum efficiency for a counter-current heat exchanger (double flux controlled motorized ventilation)
I am not sure if I can explain the question correctly because I don't know the name of this mechanism in English.
This is my explanation attempt: In a house, a tube is expelling the air from the ...
1
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1answer
209 views
Per unit area, is there more heat transfer through the open top of a mug or the side walls?
I had a mug of hot coffee cool too rapidly for my liking the other day, which made me wonder what was the greater contributor to heat loss for a typical open-top ceramic mug: the open top, the walls, ...
1
vote
1answer
348 views
When a color LCD/LED display is off it is black, when on it is colored. What color to light is an LCD/LED display
When a modern display using pixels is turned on its colors are different than the black that the screen is actually made up of. When put in light, such as sunlight, does the screen react to the color ...
1
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1answer
137 views
Does a Peltier Thermoelectric layer make a good regulator for LN2 heat-sink interfacing
I understand that when cooling water with LN2 directly (through pipes for example), that it can be too effective, freezing the water (and blocking the pipe).
From what I read, regulation of the heat ...
0
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1answer
125 views
Ideal gas temperature and pressure gradients?
Consider an ideal gas in a $d\times d\times L$ box with the $L$ dimension in the $x$-direction. Suppose that the opposite $d\times d$ sides of the box are held at temperatures $T_1$ and $T_2$ with ...
0
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2answers
334 views
How can I measure the conductivity of a copper rod?
I would like to perform an experiment to measure the conductivity of a copper rod. What device can I use to perform to experiment? is there such a thing as a conductivity meter? All i found was an ...
0
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1answer
137 views
Is this a simple system in which no heat transfer is possible?
Let's say that a hot gas is trapped in a metal box. This metal box is magnetically suspended in another structure with a low temperature. The inner box does not touch anything. And there is a void in ...
0
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2answers
66 views
Is it possible to “add cold” or to “add heat” to systems?
Amanda just poured herself a cup of hot coffee to get her day started.
She took her first sip and nearly burned her tongue. Since she didn't
have much time to sit and wait for it to cool down, ...
0
votes
1answer
250 views
Calculating (Glass) thermal conductivity
I read that glass has a thermal coefficient of 0.8-1 W/mK. Given that my window window thickness is around $5\ mm$, then I would calculate my heat loss per area being $160-200\ Wm^{-2}K^{-1}$.
Yet ...
0
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1answer
156 views
Energy loss in pipe/hose with hot water (how its affected by pipe/hose size, temperature)?
I'm working on low budget small solar power project.
I want to transport heat (peak heat power about 1kW) over ~10 meter (~30ft) long pipe or hose.
I was thinking about thin hose (6-8mm / about 1/4 ...
0
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1answer
57 views
Time constant of ice melt
I'm familiar with problems of "how much ice can you melt given some amount of energy", but I'm writing to get some clarification on the time constant of this event. This question might be somewhat ...
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0answers
33 views
Thermal Physic ($\lambda$) and ($C_p$) calculation for multilayer wall [closed]
I would like to know, how could I calculate the Thermal conductivity ($\lambda$) and heat specific ($C_p$) of Multilayer wall? (I have a wall with 9 layers which are included wood and air)
0
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0answers
542 views
What is the insulative value of water?
I am having a hard to finding what the R value of water is. I am trying to compare it to styrofoam (which has an R-Value of 5).
EDIT
Based on the assumption that water has an insulative property, ...
-1
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1answer
165 views
At the atomic level, is heat conduction simply radiation?
Radiation and conduction are two ways that heat is transferred. Convection isn't really a mode of transfer as the actual heat transfer really occurs through radiation/conduction and not by some other ...
-2
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1answer
223 views
Why do phonons cause excellent heat conduction in diamonds?
Phonons are the quantum of lattice vibrations in crystals and are not to be confused with photons, the gauge bosons of the electromagnetic force. Apparently, they contribute to heat conduction, but I ...
