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.

learn more… | top users | synonyms (1)

1
vote
1answer
695 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 ...
6
votes
1answer
2k views

Why does an infrared thermometer display very low temperature when being directed to the outer air?

I'm toying with an infrared thermometer - one which you point onto an object, press the button and it instantly measures the temperature by estimating the infrared radiation from the object. It shows ...
6
votes
3answers
16k views

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 ...
2
votes
1answer
53 views

Why does hot air rise?

Why does hot air rise? I did an experiment: I made a model of hot air and cool air with marshmallows and toothpicks. The hot air had more volume than the cold air. Then, I weighed it. They both ...
1
vote
0answers
16 views

Given temp and conductivity can I back-calculate to resistance, in order to plug in a new temp value and calculate a more accurate conductivity?

Background: I used a small CTD (conductivity, temperature, depth) recorder to log a series of dive profiles in a mixed coastal estuary. The recorder logged observed temperature and conductivity every ...
0
votes
0answers
53 views

What are the Fermi and Debye temperature constants?

What are the Fermi temperature and Debye temperature constants? We were discussing these in class and I don't fully understand what these constants are or why we have them. Can anyone explain?
5
votes
3answers
5k views

How to calculate the evaporative cooling rate needed to protect a house from forest fire

Recently in our area there has been a large forest fire and I've been looking into home defense from such things. I am not a physicist - but can do some basic math. I was wondering how I could ...
5
votes
1answer
159 views

How hot is your photon?

This question comes from my answer to the question Can a cubic meter of space at absolute zero have any object with mass inside? and the related discussion under it. To summarize, I stated that the ...
2
votes
3answers
387 views

Can a cubic meter of space at absolute zero have any object with mass inside?

I ask this question because, I have seen many places where they say the average temperature of the universe is some 2 degrees K and this somehow relates to mass present within a given volume of space. ...
0
votes
0answers
34 views

absolute minimum vs absolute maximum [duplicate]

there is such a thing as a absolute minimum temperature defined by At the physically impossible-to-reach temperature of zero kelvin, or minus 459.67 degrees Fahrenheit (minus 273.15 degrees ...
7
votes
4answers
668 views

Existence of negative temperatures and the definition of entropy

How negative temperatures can be possible has been treated on StackExchange before (several times in fact), but in light of some recent academic discussion, most of these answers seem to be possibly ...
0
votes
1answer
76 views

How to calculate precipitation chance with basic weather data?

I would like to know if there is any algorithm which allows us to calulate precipation chance with following data: temperature, humidity, illuminance (in lux) and pressure. I've searched it in google, ...
-2
votes
1answer
57 views

Why does a thermal memory need a thermal bath?

In the article "Thermal Memory: A Storage of Phononic Information Phys. Rev. Lett. 101, 267203 – Published 29 December 2008" it's said that a thermal memory need a thermal bath, similar to a power ...
0
votes
0answers
74 views

Trying to determine transient response of air conditioned room

I have an air conditioned room which intakes airflow at temperature $T_{in}$ at a mass flow rate $\dot m$. The air leaks out of the room at mass flow rate $\dot m$ and temperature $T_{room}$. The room ...
1
vote
3answers
253 views

Determining a temperature increase from heat energy [closed]

A 15.0g bullet traveling horizontally at 865 $\frac{m}{s}$ passes through at a tank containing $13.5$kg of water and emerges with a speed of $534\frac{m}{s}$. What is the maximum temperature ...
3
votes
2answers
3k views

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, ...
2
votes
4answers
211 views

What is planetary surface temperature given constant sub-surface temperature?

If a planet of radius $R_1$ has a constant sub-surface temperature $T_0$ at $R_0<R_1$, what is the long-term equilibrium surface temperature $T_1$? Say we assume constant thermal diffusivity of ...
1
vote
1answer
199 views

How does the entropy change during the cooling of a hot coffee in a cold cup?

The second Law of Thermodynamics states that entropy always increases in the universe: things become more disorganised. This means, that if I have a hot coffee in a cold cup, then the heat will ...
0
votes
0answers
78 views

Constant volume gas thermometer

Well, in the notes I took in thermodynamics' class I have a graph that plots Pressure of boiling point $P_b$ over Pressure of freezing point $P_f$ at constant volume in terms of Pressure of boiling ...
1
vote
1answer
87 views

Increase in Solubility of a Gas with an Increase in Temperature

On the UC Davis ChemWiki I read, "some gases have an increase in solubility with an increase in temperature." I understand why this is applicable to solids in liquids such as water, but why is it ...
0
votes
1answer
108 views

How does heating in the atmosphere look above 100 km

I have tried without luck to find a graph of temperature change through the atmosphere that goes further up than about 100 km. On this graph: (Source: ...
0
votes
1answer
65 views

Thermometric Properties

A thermocouple thermometer with 10 ohms of resistance is calibrated with its hot junction and cold junction immersed in steam and melting ice respectively. An EMF of 5.6mv is measured. This ...
0
votes
1answer
74 views

Linearity of thermal expansion of metals?

I am having to do a path length correction for a metal tube (stainless steel 316, 16ppm/C) from 0-100 degC. I need to correct to within approximately 1 ppm. How much do typical engineering metals ...
0
votes
4answers
108 views

Why don't the collisions of the particles in a gas affect its temperature?

Temperature is defined as the mean kinetic energy of the system. Now the particles are constantly colliding with each other; as a result of which kinetic energy of each particle changes. ...
1
vote
0answers
11 views

PCF based temperature sensor [closed]

how to calculate relationship of refractive index And temperature for liquids in optics and what are the methods?
1
vote
4answers
1k views

Relation between temperature and pressure?

I was just working on a special question but I ignored the effect of temperature on it and now it becomes very important to me. What is the relation between Pressure and Temperature? Suppose we ...
2
votes
3answers
55 views

Solar plants and energy conservation

I'd like to apologise if this question is stupid or if it was asked ten thousand times - I haven't found an answer to it. Quite possibly due to mediocre English or abominable knowledge of physics. ...
2
votes
2answers
80 views

Why do we call a white led with high color temperature “cool”?

one can buy LED bulbs with defined color temperature. why cool white = many kelvins (= high temperature?) why warm white = few kelvins (= low temperature?)
1
vote
0answers
49 views

Temperature as the independent variable of Lagrangian

I was thinking about applications of the Lagrangian and I started to toy with some ideas and tried to come up with interesting twists. Immediately I thought it would be interesting to use temperature ...
0
votes
1answer
63 views

Why is temperature vibration?

Why do the atoms in a crystal vibrate at finite temperature?
8
votes
4answers
812 views

Hot water freezing faster than cold water

This question has puzzled me for a long time. There is already a question like this on Physics.SE. John's answer to the question seems quite satisfying. But when I googled the cause I found this and ...
3
votes
3answers
111 views

Average temperature of the universe

Is it possible to define some average temperature of the universe? If yes, what fixes this temperature and how t estimate today's temperature? Is it different from the temperature of the black-body ...
2
votes
2answers
1k views

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: ...
1
vote
2answers
231 views

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 ...
0
votes
1answer
3k views

Mixing Water at Different Temperature

If I have cup of water at room temperature (say, $25^\circ$C). What would be the resultant temperature if I pour another cup of same amount of water at $100^\circ$C to it? Is it simply ...
0
votes
1answer
75 views

Could the uncertainty principle theoretically be violated at 0 K? [duplicate]

Ok so please excuse me if the following mental argument is completely ridiculous or obviously flawed :P I was reading about how, even at 0 K (assuming we could experimentally reach such a ...
0
votes
1answer
47 views

Blowing on a hot liquid [duplicate]

Lets say you have a nice bowl of piping hot soup. You use your spoon and take a sip and realize its too hot. So you blow on it a few times and now its cooled enough that it doesnt burn your mouth. ...
1
vote
0answers
47 views

Finding the temperature of Earth from temperature of Mars and its distance from Sun [closed]

I am to compute the temperature of planet--in fact I've already found out it's Earth--knowing only: the surface temperature of Mars (210 K) and its distance from Sun (1.524 AU) and of course ...
1
vote
2answers
232 views

Balloon gas temperature experiment in water

In this problem set I have a passage that describes an experiment that looks at the changing temperature as an air filled balloon rises to the surface from the bottom of a water filled tank. The graph ...
0
votes
0answers
24 views

PT100 calibration

I have also asked this on the electronics group, but it is equally relevant to physics of temperature mearurement If I take (say) a class B PT100 sensor with a stated absolute accuracy of +/- 0.3 deg ...
3
votes
1answer
77 views

Is there a “high temperature” variant of 0 degrees Kelvin? [duplicate]

I know that -273.15 degrees celsius, also known as Absolute Zero or 0K is the low temperature limit for objects, but is it possible that there is a 'highest temperature?' I would have to guess that ...
1
vote
0answers
91 views

Negative temperature thermodynamics

I asked this question about thermodynamics. I considered $$T=\frac{\partial U}{\partial S}$$ at constant $V$ and $N$ (number of particles), but now I can't figure out the change of $U$ with respect ...
3
votes
2answers
2k views

How are the CPU power and temperature caculated/estimated?

From Wikipedia The power consumed by a CPU, is approximately proportional to CPU frequency, and to the square of the CPU voltage: $$ P = C V^2 f $$ (where C is capacitance, f is ...
3
votes
3answers
3k views

How can I determine density of a gas only given temperature?

I have a homework problem where exhaust is traveling through an exhaust system (assumed to be air for simplicity) from and engine and then released into the atmosphere. The exhaust is at a temperature ...
1
vote
1answer
44 views

Is it true that a processor with a higher temperature uses inevitably more power in comparison with a processor with a lower temperature?

If a processor has a higher temperature, can you be sure it it consumes more power than a processor with a lower temperature? And is the reverse relationship true? A processorchip with a higher mean ...
1
vote
1answer
64 views

How is heat and temperature related? How will a thermometer react in the following conditions? [closed]

Consider the cooking stove and LPG fuel for example, all my questions will be related to it. Assume I have a frying pan made of steel which is kept on the the stove with the knob set to moderate. ...
1
vote
0answers
49 views

What does the temperature of the early universe tell me?

I am re-reading Weinberg's book "The First Three Minutes". In the Introduction he makes this statement: "At about one-hundreth of a second, the earliest time about which we can speak with any ...
0
votes
0answers
60 views

Effects of pressure rate of change on the temperature of a fixed amount of gas

In Vol I,Chap 1-2 of the Feynman lectures on Physics,Feynman talks about how a change in pressure of a fixed amount of gas enclosed in a piston can cause its temperature to increase/decrease. He ...
9
votes
1answer
679 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 ...
9
votes
3answers
1k views

What is the relationship between Maxwell–Boltzmann statistics and the grand canonical ensemble?

In the grand canonical ensemble one derives the expectation value $\langle \hat n_r\rangle^{\pm}$ for fermions and bosons of sort $r$: $$ \langle \hat n_r\rangle^{\pm} \ \propto \ ...