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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Temperature; Why A Fundamental Quantity?

Temperature is just an indication of the combined property of mass of the molecules and their random motion. We can explain no effective energy transfer between two conducting solid bodies in contact ...
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1answer
235 views

if one electric heater makes the room 25 degrees, will two make 50?

The question in the title is of course childish and the answer is NO... But then how much if not 50 degree ? lets give some more data: we have a electric heater with NO temperature regulation and ...
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1answer
109 views

Thermodynamics, temperature below 0 Kelvin [duplicate]

I read a news article about how they were able to create a negative temperature, below absolute zero, and my question is how does this work? I know that there are different definitions of ...
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2answers
247 views

If quantum gas goes below 0K, is calling 0K absolute zero irrelevant?

Lord Kelvin defined the absolute temperature scale in the mid-1800s in such a way that nothing could be colder than absolute zero. Physicists later realized that the absolute temperature of a gas is ...
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1answer
86 views

Unheated intermediate room - positive or negative effect on flats temp. insulation?

This is a question I have heard quite some contrary opinions, so I want to ask it here, as it deals with physics in principle:) The question is basically that, if having a unheated intermediate (in ...
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121 views

Can Planck's temperature ever be reached?

Planck's temperature is theorized to be the highest possible temperature in the universe. But, has it been reached? Or, will any object or phenomenon ever reach this absolute temperature?
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80 views

Temperature of thermally isolated space region

If we thermally isolate a region in space, say using a hypothetical material of $0$ conductivity, and measure the region's temperature, will it be 2.7K?
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29 views

What is the suitable temperature for a motor to work without failing? [closed]

How much body temperature can a motor withstand along with the ambient temperature to work without failing?
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1answer
318 views

Ice bath is always 3C, why?

I've always learned that a mixture of ice and water should reach equilibrium at approximately 0C. I've actually tried to create that a number of times in different contexts and always fail. First, ...
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41 views

Optimal temperature for Mpemba Effect

Is there an pptimal temperature for the Mpemba Effect? Is there an optimal initial water temperature for speedy freezing? If so, what is it? If a specific example is needed: There is a 100 milliliter ...
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813 views

Temperature below absolute zero?

I saw this Nature article today, which cites e.g. arXiv:1211.0545. And it makes no sense to me. The temperature of a collection of particles is the average kinetic energy of those particles. Kinetic ...
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1answer
95 views

What is the de Sitter temperature as of now?

It is claimed that de Sitter temperature is $$T=\frac{1}{2\pi}H,$$ where $H$ is the Hubble constant. I presume it is expressed in natural units with which I am not familiar. So what it will be in ...
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1answer
20 views

The common major difference in thermal conducting properties between a random rock sample and metal?

what are some common major differences in thermal conducting properties between a random rock sample(non-metal) and metal?
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1answer
323 views

Setting up an equation for calculating how long it takes a body to change temperature in its sorroundings

The United States has just recently been hit by a massive vortex of Arctic air. These unusually bitter temperatures have sparked my interests to ask the following rheotical question: How much time ...
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206 views

How would a physicist measure temperature of molten metals in 1850-1920s?

How would a physicist measure temperature of molten metals in 1850-1920s? What equipment would be used?
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3k views

Ideal gas law, pressure increase and temperature

If I had a container, full with air, and I suddenly decreased the volume of the container, forcing the air into a smaller volume, will it be considered as compression, will it result in an increase in ...
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1answer
124 views

Semiconductors: why the mass action law is not valid for very low temperatures?

I thought that it was valid for very low temperatures since for it to be valid I think that it is necessary to be in the non-degeneracy condition, which requires $E_G >> k_B T$ (with $E_G$ being ...
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0answers
34 views

What is highest temperature which is attainable? [duplicate]

We all know that there is a limit to the lowest temperature which can be achieved i.e. $0K$. But I wanted to know if there is a limit to the highest temperature which can be attained. And if there is ...
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1answer
110 views

is this heat calculation equation correct?

If I have a line of copper wire (lets say $\textrm{1 meter}$ long, $\textrm{1 mm}$ thick) and one end is a flattened disk of copper about the size of a quarter, and I apply a lot of heat to it (I'm ...
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408 views

A draft makes people feel cold. How can that be measured?

On some days our office feels very cold to the point at which we find it difficult to type because our hands have gone numb. But our facilities manager insists it is the same temperature as always. ...
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1answer
60 views

Why would the environmental lapse rate be slower near the ground?

I have data taken from over 2300 ascents through the atmosphere at various locations around the world, for every 500 meters vertically upwards I have averaged the temperature and plotted it: Its ...
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1answer
317 views

How is NASA's mod II Stirling engine so powerful yet so small?

Is it because of the temperature difference? I just don't understand how it can propel a car. Here's the link to the engine: ...
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1answer
302 views

How effectively does heat flow through copper wire?

If I have a line of copper wire (lets say 1 meter long, 1mm thick) and one end is a flattened disk of copper about the size of a quarter, and I apply a lot of heat to it (I'm talking 800 Celsius) will ...
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1answer
110 views

How do Stirling engines work?

How do Stirling engines work? I understand the heating and cooling of air, but how much faster (or more force, I'm not sure which to use) does the piston move per degree Celsius that the temperatures ...
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1answer
62 views

Question about the refraction of Fresnel lenses

If you line up the suns rays parallel to a Fresnel lens, the light is concentrated, and the focus directly underneath. However, what happens if the sun is off to the side, making the light hit at an ...
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1answer
51 views

Does thermal energy change within a chamber depending on what's in it, where it is, what it is?

I have noticed that some people will say that, when you put more mass in an oven, it takes longer for both to cook than if just were one. Some others will say that timings are the same. Assume we ...
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1answer
710 views

Is temperature of a single molecule defined? [duplicate]

Is temperature of a single molecule defined? This question just cropped up in my mind as I have often heard of laws being violated when it comes to the scale of a single molecule. Does this happen in ...
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Is temperature a Lorentz invariant in relativity?

If an observer starts moving at relativistic speeds will he observe the temperature of objects to change as compared to their rest temperatures? Suppose the rest temperature measured is $T$ and the ...
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Which direction does air flow?

I remember learning this in high school, but have forgotten it, and can't seem to find it anywhere online. Air travels from areas of high pressure to low pressure...correct? So if I have a cold room ...
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2answers
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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 ...
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Why are refrigerators 4 degrees and freezers -18 degrees?

I assume that the refrigerator's temperature of 4 degrees has something to do with the fact that water is densest at that temperature. Does that inhibit microbe growth? But what about the freezer, ...
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339 views

How much does increased world population contribute to global warming?

In 1974 there where 4 billion people on earth. Now in 2013 we passed 7 billion people. So the world population is nearly doubled in 40 years. Every living human being also haves a body temperature of ...
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127 views

Second derivative of vapor pressure from a cubic equation of state

It is quite easy to compute the first derivative of vapor pressure with respect to temperature from a cubic equation of state at least at the critical point since there is a continuity with the ...
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55 views

Linearity of the critical isochore?

When looking at the pressure-temperature diagram along the critical isochore (up to quite high reduced temperatures) a very linear trend can be observed. From a theoretical point of view, is the ...
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275 views

If the universe is full of dark matter, why is it only 2.73 K cold?

people! I am just a physics layman, but I recently watched a documentary about the universe and it was told that the universe is full of dark matter and energy and the universe is empty, so that ...
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What is the logic behind the Fahrenheit scale?

The Fahrenheit scale is defined by fixed points on the scale. What interests me is the apparent arbitrary chosen numbers in these fix-points. First wikipedia wites from 32 to 212. -and later in the ...
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188 views

What is the temperature of a quantum particle in a box?

Some simple examples in textbooks include simple 1D systems such as particle in an infinite potential well or in harmonic oscillator potential. It is also said that at absolute temperature of the ...
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226 views

What is the name of the temperature limit beyond which an explosion will form a mushroom cloud?

Many months ago I saw a picture that was taken many years ago of an explosion, possibly in the Atlanta area. If I recall the explosion was caused by fuel in railroad cars. However, the explosion ...
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Temperature in CGS (Gaussian) units

I've been struggling with conversion from Gaussian to SI units for sometime, trying to figure out how derived units in CGS (current, charge etc) relate to the SI units. But I couldn't find any ...
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How Temperature, Pressure and Altitude are related in the atmosphere?

I'm looking for an approximation for the temperature of the atmosphere at any height and pressure. Both altitude and pressure are known variables, I've derived this equation using maxwell's ...
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Doesn't the use of a thermometer alter the temperature of the system?

If I place a mercury thermometer in hot water, heat energy will transfer from the water to the mercury inside the thermometer. Will this continue until thermal equilibrium is reached and thus the ...
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6answers
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Celsius to Fahrenheit confusion: why there is no 1 to x ratio

Why is it not possible to know ratio of 1 degree to how many Fahrenheit and use that to convert from or to Celsius/Fahrenheit. I mean what is really happening. Fahrenheit increases linearly and so ...
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1answer
282 views

Work done on gas by piston [closed]

In this problem there is a cylinder that is closed at both ends and has thermally insulated walls. It is divided into 2 parts by a movable, frictionless, thermally insulated piston. There is a ...
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1answer
400 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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3answers
351 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 ...
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2answers
365 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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Is there an equation for convective heat transfer?

Is there an equation I can use to calculate the temperature (as a function of time) of an object which is gaining or losing heat by convection? Or equivalently, the rate of energy transfer from the ...
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1answer
92 views

Why basements stay cold even during summer?

Why a room below the surface (such as basements) can stay cold all the time? How is it able to avoid the high increase of temperature and heat in hot days and periods?
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1answer
63 views

Determining if a solution will boil

A piston compresses a solution of 40% $HNO_3$ in $H_2O$. If the piston breaks and the pressure is reduced from 12.0 atm to 1.0 atm: a) If the temperature of the solution is 110 degrees C, will the ...
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Temperature limit of the increase in heat

If the sun is the hottest known thing to humans is it possible to have a temperature greater than the sun?