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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60 views

Heating 2 sets of 1L water vs 1 set of 2L water [closed]

Can heating 2 sets of 1L water or 1 set of 2L water have a variation in terms of fuel efficiency? Can one be more fuel-efficient than the other? (migrated from chemistry site)
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1answer
73 views

How to calculate the increase in temperature due to drop? [closed]

Question- Calculate the rise in temperature in celcius in a bucket of water after it is dropped from 50 m where acceleration due to gravity is 10. I know that I need to find the amount of energy ...
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1answer
43 views

Does shaking a carbonated soda warm it up?

I had an odd situation where i left a soda near the fridge exhaust and it developed some ice crystals (i could hear it sloshing). When i took it out i instinctively shook up the closed soda can with ...
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2answers
64 views

Thermodynamic expectation value at $T=0$

The thermodynamic expectation value for an observable $A$ is defined as $$\langle A \rangle = \frac{1}{Z} \sum_n \langle\psi_n| e^{-\beta H} A|\psi_n \rangle, \qquad (1)$$ where $\beta=1/k_bT$, the ...
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1answer
45 views

Method used to prove emissive power, $E \propto T^4$

Stefan's Law states that emissive power($E$) of a black body is proportional to $T^4$. But how did Stefan arrive at the conclusion? I mean, it is not possible currently to get a perfectly black body, ...
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2answers
5k views

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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1answer
23 views

Temperature moderation

Temperature moderation is closely related to the hydrogen bond, as you guys all know. And this temperature moderation happens everyday to human beings through perspiration. As the water in you body ...
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0answers
47 views

WIll aluminium foil get hot in microoven if I wrap it with paper?

A aluminium foil doesn't get hot easily because of it's heat conductivity. Will it get hot in microwave oven if I wrap it with paper?
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0answers
15 views

Sliding Wine Glass [duplicate]

Earlier today, I came across a strange phenomenon involving a just-washed wine glass and a countertop. The gist of it is: when you place a warm wine glass upside-down on the wet countertop, it starts ...
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3answers
137 views

The temperature in space is about 3K, however there are almost no atoms in space. How can there be residual heat?

My understanding is that heat is essentially atomic vibrations. If there are almost no atoms, how can there be residual heat? Also, as I understand in space there is no heat transfer via convection ...
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2answers
74 views

What is the physical explanation for the heat equation?

We know that $\int{\vec v.\vec n \,\ d a}$=$\int{\nabla^2(u)\,\ dx \,\ dy \,\ dz}$ where $\vec v$ is the velocity of the heat flow and $u(x,y,z)$ is the temperature at the point $(x,y,z)$.and $ \vec ...
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2answers
758 views

How to interpret Stefan-Boltzmann's law?

The Stefan-Boltzmann equation states $e=\sigma T^4$, but how do we interpret this? Is this completely wrong: A body of size $s^2$ generates the radiation/temperature $T^4$ for a given size and a ...
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1answer
1k views

How do I keep the temperature constant in a Boyle's Law experiment?

I'm trying to get a head start on our lab experiment next week about Boyle's Law. The set-up is we have an air chamber can immersed in a pot of boiling water (which is kept boiling over an electric ...
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2answers
141 views

At what wind speed does wind chill's conductive cooling exactly cancel out the compressive heating of the air?

At relatively slow wind speeds such as 15mph, wind chill drains heat from an object as it flows past, and this conductive cooling effect seems to increase as the wind speed increases. However, at very ...
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1answer
113 views

Will I weigh more if I have fever?

$E=mc^2$ means that energy is mass, and adding energy to an object (that is, making it hotter) makes it more massive. So if my body temperature increases, will I weigh more? or will i become lighter ...
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1answer
577 views

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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8answers
23k views

Why does hot water clean better than cold water?

I had a left over coffee cup this morning, and I tried to wash it out. I realized I always instinctively use hot water to clean things, as it seems to work better. A Google search showed that other ...
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1answer
70 views

Why does the stiffness of organic polymers (plastic) change so much with small changes in temperature?

This is on the borderline between Physics and Chemistry, but I would like a Physics perspective. I am guessing that plastics are a glass-like phase, rather than a true solid.
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1answer
38 views

Why is metal stiffer at lower temperatures?

Each morning I cycle to school and lock my bike with a thick steel wire (about 8 mm thick). I noticed that it's much harder to change the shape of the wire in the morning when it's much colder than ...
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5answers
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Why has Earth's core not become solid?

The Earth is billions of years old, yet its core has not yet cooled down and become solid. Will this happen in the foreseeable future?
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1answer
41 views

Why do high altitudes have larger diurnal temperature variation than lower altitudes?

It seems like the lack of atmosphere should not be playing a role in the diurnal temperature variation because that's what makes it colder. Mountains are not that dry, usually.
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2answers
201 views

How hot is aurora?

Has anyone done research on how hot aurora is? I mean if it is plasma it should be hot and since it is emitting mostly green light due to nitrogen (~78%) in the air, could it then be considered that ...
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2answers
85 views

Can Maxwell's law of distribution of velocities be used to determine a value for absolute heat?

I'm currently reading about Maxwell's law of distribution of velocities, and the thought occurred to me that I could use this to calculate the maximum temperature that an atom could reach. My theory ...
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1answer
22 views

How does an object in vacuum loose its temperature? [duplicate]

Well, it radiates in the infrared, I guess. But how exactly are these photons created? The atoms have some kinetic energy, which makes up the temperature. So while the atoms or molecules jitter a bit ...
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2answers
415 views

Arrhenius Fit: Linear or exponential form?

I have a seemingly easy question about performing an Arrhenius fit to the equation $$y = A \times \exp \left( -\frac{E_A}{RT} \right)$$ I can either fit this in the exponential form using a ...
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2answers
1k views

What's the difference between a positive and a negative current?

Say I have a wire, and I connect a current source on its left end, and a ground to its right end. Then using my power supply I source a positive current, does this mean that electrons will move from ...
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1answer
94 views

Quicker way to cool liquid

I need to prepare a bottle of baby milk from formula quickly. To prepare it I must use some boiling water to sterilise the powder however it must be served at just above room temperature for the baby ...
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1answer
45 views

Need Some Help Creating A Couple Of Equations [duplicate]

I've posted about this project before as math is not at all my strong subject anymore. I have a couple sets of data and I need to make some equations for them. I've used Excel to get trend lines, but ...
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5answers
29k views

Why less temperature at high altitude

Why there is always cold at high altitudes. e.g. at peak of mountains. Also as we go high from sea level, temperature starts decreasing. Why is it?
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2answers
83 views

Temperature rise in Thermosphere

Generally speaking, temperature decreases as altitude increases from the sea level. But at the ozone layer it increases because ozone absorbs UV radiation. Temperature increases again in Thermosphere. ...
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5answers
186 views

What would the RBG color value of an infinitely hot blackbody be?

In other words, what is the limit of the rgb values of color temperature as temperature approaches infinity? Put differently, what is the terminal point of the Planckian locus? Is there an exact ...
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3answers
2k views

Can two bodies having the same internal energy have different temperatures?

According to me, two objects having the same internal energy may have different temperatures if their masses and specific heats are different and it is possible that an object with more internal ...
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0answers
93 views

Is temperature a frame dependent quantity? [duplicate]

The temperature of an object is proportional to the average kinetic energy (1/2*m*v^2) of its particles (or molecules), then shouldn't the temperature depend on the frame of reference since v^2 will ...
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866 views

Why isn't temperature frame dependent?

In (non-relativistic) classical physics, if the temperature of an object is proportional to the average kinetic energy ${1 \over 2} m\overline {v^{2}}$of its particles (or molecules), then shouldn't ...
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1answer
156 views

Why is temperature vibration?

Why do the atoms in a crystal vibrate at finite temperature?
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3answers
1k views

Why is boiling not just a surface phenomenon?

The boiling point of a liquid is defined as The temperature at which the vapor pressure of the liquid is equal to the external atmospheric pressure. That being the case, why, in a pot of boiling ...
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1answer
54 views

Do ice balls in whiskey really make sense?

So, I get the ad copy, the surface area to mass ratio results in more cooling, less dilution. But does this actually make sense? Yes, total cooling is related to the mass/temp of the ice, not the ...
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2answers
4k views

Can jet fuel melt steel beams? [closed]

Common sense suggests that steel beams should not yield under burning jet fuel without presence of other substances that produce very high temperatures when burning, such as thermite. So can jet fuel ...
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1answer
108 views

Calorimetry - Emitted Joules [closed]

How can one calculate the total amount of emitted joules from an object with a temperature that isn't constant? A great start is this formula: ...
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1answer
159 views

How to calculate water temperature from a room temperature? [closed]

e.g. My room temperature is about 33 degree celsius How can I calculate water temperature in the tank in my bathroom? Note that my tank is one side open up and it build up from bricks
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2answers
126 views

Help Writing An Equation [closed]

Truthfully, math past basic algebra was never my strong suit even though I went through stats in college. So I have to write an equation for this for a program and could use some help. I am reading ...
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11answers
57k views

Why does the gas get cold when I spray it?

When you spray gas from a compressed spray, the gas gets very cold, even though, the compressed spray is in the room temperature. I think, when it goes from high pressure to lower one, it gets cold, ...
11
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7answers
4k views

Why does heat added to a system at a lower temperature cause higher entropy increase?

Entropy is defined in my book as $\Delta\ S = \frac{Q}{T}$. To derive the formula it says that entropy should be directly proportional to the heat energy as with more energy the particles would be ...
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0answers
49 views

Equilibrium temperature of the universe [duplicate]

At what temperature will the universe eventually equilibrate?
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0answers
62 views

Entropy definitions

So I have learned that entropy is the measure of disorder of a system. For the IPhO this was of course not enough as we need to be able to calculate entropy changes of ideal gases. Those equations ...
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1answer
590 views

What's the most fundamental definition of temperature?

What's the most fundamental definition of temperature? Is it the definition concern about average energy, number of micro states, or what? By "fundamental", I mean "to be applied" in such general ...
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1answer
2k views

Thermodynamics for Dummies: Entropy and temperature

I do not study physics and I have never had a course in thermodynamics. I have no idea what it is about, but I am currently taking a course where we had something about entropy. Would be great if ...
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2answers
403 views

Dimensionless entropy interpretation

Measuring temperature in joules instead in the artificial units of Kelvin would render entropy as a dimensionless quantity. This is quite appealing since entropy has always been quite a misterious ...
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5answers
846 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 ...
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Effect of temperature on radioactivity?

I'm researching the effect of temperature on uranium radioactivity, however I can't find any solid empirical evidence to prove the notion that temperature does not affect radioactivity. Can anyone ...