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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Definitions in thermodynamics: temperature, thermal equilibrium, heat

I'm currently reading Fermi's "Thermodynamics" and I'm trying to grasp the (possibly different) right definitions for temperature, thermal equilibrium, heat. To clarify, I'm looking for definitions ...
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What happened to high temperatures in the universe?

We know that after the big bang the temperature was about 10^32 K. But now the average temperature of the universe is about 4 K. What happened to the temperature at that time? Where did it go?
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842 views

Help with calculating resistance at a given temperature

The resistance of a bulb filament is $100\Omega$ at a temperature of $100^\circ \text{C}$. If its temperature coefficient of resistance be $0.005 \space \text{per} ^\circ \text{C}$, its resistance ...
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302 views

CMBR temperature over time?

How has CMBR temperature dropped as function of time? A graph would be nice, but I'd be happy with times (age of universe) when it cooled enough to not be visible to human eye, became room temperature ...
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25 views

Is the current situation possible for recreaction in a lab?

I want to convert cellulose to another form (crystalline => amorphous). Cellulose requires a temperature of 320 °C and pressure of 25 MPa to become amorphous in water.(Is the pressure achievable in ...
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When is temperature not a measure of the average kinetic energy of the particles in a substance?

I had always thought that temperature of a substance was a measure of the average kinetic energy of the particles in that substance: $E_k = (3/2) k_bT $ where $E_k$ is the average kinetic energy of ...
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452 views

Measuring temperature at a distance

http://www.youtube.com/watch?v=gKYrXHZwtPw In this video it is explained that Land Skin Temperature (LST) are measured by NASA's Aqua and Terra satellites. It seems it works by collecting the ...
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Photon temperature above Electroweak Symmetry Breaking (EWSB) transition

In discussions of the history of our Universe, photon temperature is substituted for time. As the Universe cools, phase transitions break symmetries, including electroweak symmetry. Why does it make ...
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Opening the fridge door to cool a room

I'm well aware that the default answer to this textbook default question is "it doesn't work", but still, I believe it does. To cool the insides of the fridge, the compressor must do work, and since ...
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887 views

What's the best strategy to fully fill the fridge with beer bottles and have them all cooled?

I'm having a party. Suppose I'd like to have a fridge full of cold ($6~^\circ\text{C}$ or below) beer bottles, in as short a time frame as possible. The fridge indicates that it is targeting (and ...
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2k views

Why does a breeze of wind make us feel cooler? [duplicate]

In my Astronomy class, I learned that temperature results from the speed of air molecules colliding into your skin. Thus, if the air molecules in the room have a high kinetic energy and thus collide ...
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227 views

Temperature of rod if end points are different temperature [closed]

How does the temperature vary along the length of the rod if its both ends are at different temperature. As an example, consider the problem: 20 cm long rod has rod at one end 100 ºC and another ...
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273 views

In a large city how much hotter on average is it outside due to the air conditioning of all the buildings?

Title pretty much states the question. How much hotter do air conditioning units make it outside in a large city like NYC, Chicago, etc?
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645 views

Why do we feel a sudden chill?

When we are in a room, especially in some old houses, we feel this sudden rush of cold air. How does a strong air current arise and pass away so quickly?(lasts for about a second) I know air-currents ...
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1answer
40 views

Organs & Oscillations: An Analysis on the Temperature Dynamics of Solids

Does temperature have an influence on the frequency of an oscillating organ pipe?
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356 views

Why do some air-conditioned stores blast you with jets of air as you enter?

I went to a grocery store on a hot day that was very well air-conditioned, and I noticed as I went through the open entrance that there seemed to be a very powerful downward air current right at the ...
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262 views

ideal gas law modelization in a vacuum chamber

I am trying to model a pressure sensor in COMSOL. The basic work is that there is current flowing inside it, if the pressure of the gas around it drops down, the temperature goes down as well (ideal ...
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Time required for water to freeze

recently I was wondering if there is any specific formula in order to calculate how long it takes for certain liquids to freeze (especially water). I know this depends on: the volume of the liquid, ...
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1answer
460 views

How much does sunlight affect inside temperature?

Suppose we have a $3\cdot 3\cdot 3\,m^3$ room of which one side is glass. And suppose that the other 5 sides have no effect on temperature (super isolation). We know from physics how to calculate ...
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886 views

Best way to chill a cup of coffee with cold water and 5 minutes [duplicate]

Initial data 1 x 3/4 full cup of hot coffee / tea / your favorite morning beverage cold water 5 minutes Considering that it's starting to get hot outside, and we all want to drink reasonably cold ...
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2answers
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How fast would body temperature go down in space?

What would be the rate of temperature loss for an average sized human in space without a suit? A human generates about 100 watt at rest. But how can we use that to calculate how fast the temperature ...
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964 views

Can a rock be considered frozen

Water usually comes to mind when thinking about freezing. Once it reaches a certain temperature, water freezes, becoming a solid. However could you make the same statement about a rock? Is a rock at ...
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1answer
62 views

Which is more efficient cooling? Cooling yourself from cold water from Referigerator or Airconditioning? [closed]

Case a: You chill a glass of water in refrigerator to a certain temperature and drink it.. it lowers your body temperature by X degrees. Case b: You switch on the a/c for a certain duration.. it ...
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1answer
381 views

Why do ice cubes make a cracking sound when placed in fizzy wine (Prosecco)?

When placing ice cubes in a fizzy drink such as Prosecco, ice makes a cracking sound, after which the fizzy bubbles more than usual. What is the physics of this phenomenon?
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Having a problem about entropy, thermodynamics

I am a high school student. So, while studying about thermodynamics, I got a little curious about entropy. As I read, entropy is the rate of change of chaos. So, if the entropy change of a system is ...
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1answer
798 views

Newton's law of cooling: changing temperature of environment

A metal ball having temperature of $80^\circ C$ is placed into $m$ grams of water at $0^\circ C$. After ten minutes, it was found that the temperature of ball and water are $60^\circ C$ and ...
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2answers
591 views

Guitar strings and temperature

I am investigating Mersenne's law with a guitar by varying tension (hanging weights) and string length. Will temperature change (room temperature to ~4°C) effect the frequency noticeably? If so, is ...
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480 views

How long does the 2nd pot of water take to boil right after the 1st one finishes?

Say I have a pot of water that boils in 20 minutes, at whatever temperature. If I leave the fire on, take the pot off, pour the hot water into a container, refill the pot with tap water and put it ...
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690 views

Why isn't the Earth's core temperature the average of its surface temperatures?

Assuming that the earth is spherical, that its temperature is continuous, and that some other more or less realistic conditions hold, we might think that the Earth's core temperature should be about ...
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1answer
282 views

Temperature gradient in body [closed]

Is there a Temperature gradient in the human body? especially I have heard that the eye is colder than other places? Is that right?
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1answer
365 views

Triple point temperature and freezing point

Why does the triple point temperature have very similar values to the freezing point, in most substances?
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2answers
4k views

Why is a degree Celsius exactly the same as a Kelvin?

How on earth is it possible that the difference between two temperatures in Celsius and Kelvin is exactly the same. Given the historical definition of Celsius, I find it hard to believe that this is ...
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4answers
926 views

Can a single molecule have a temperature?

A show on the weather channel said that as a water molecule ascends in the atmosphere it cools. Does it make sense to talk about the temperature of a single molecule?
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2answers
445 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 ...
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761 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 ...
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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 ...
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2answers
435 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 ...
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Why aren't the energies of two systems in thermal equilibrium fixed?

In the derivation of the Boltzmann distribution they consider a system $A$, enclosed by a diathermal wall in a heat reservoir $R$. Then they calculate the probability that the system $A$ is in an ...
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How can I explicit the energy dependence of the Maxwell-Boltzmann distribution?

I'm having a bit of a problem figuring out the energy dependent Maxwell-Boltzmann distribution. According to my book (Ashcroft & Mermin) they write the velocity dependent distribution as: ...
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1answer
240 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 ...
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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 ...
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56 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 ...
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Why does increasing the temperature of a thermistor decrease it's resistance?

Surely, upon an increase in temperature, the atoms within the thermistor would vibrate with more energy and therefore more vigorously, hence making the electrons flowing through the electric circuit ...
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1answer
184 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 ...
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3answers
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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 ...
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1answer
208 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 ...
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1answer
64 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 $$1/T = dS/dE$$ ?
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125 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 ...
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165 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 ...
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123 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 ...