# Tag Info

## Hot answers tagged temperature

9

Boiling is clearly not a surface phenomenon. But vaporising is. Boiling happens at all the points inside the liquid whereas when vaporising only the molecules at the surface escape into the space above. And it is true that a liquid boils when its saturated vapour pressure equals external (room) pressure. But it is not to be confused with vaporising. ...

7

Generally, bodies can have same internal energies, but have different temperatures, and vice versa, have the same temperature but different internal energies. Consider for example ideal gasses, where the internal energy is given as a function of temperature and heat capacity: $U={C}_{V}T$. If we have a monoatomic gas consisting of N particles, its heat ...

5

The quoted definition may sound confusing because of the use of "vapour pressure", which is not necessarily related to the liquid-air surface. This can be made clearer by a different example: Suppose you have a water container at room temperature and you heat only a small volume at the centre of the container (by using focused radiation of some sort, for ...

5

Given adequate oxygen, certainly. From here, for instance, you can get an approximate maximum flame temperature for kerosene burning in air, and a higher concentration of oxygen will increase the temperature. At 3800 F, this is about 1000 F above the melting point of steel, so melting steel with jet fuel (kerosene) is entirely possible. Of course, "Common ...

4

If you make the temperature very, very high (say $>10^{5}$ K) then the visible part of the spectrum lies in the Rayleigh-Jeans tail of the Planck spectrum. Thus: $$B_{\nu} \simeq \frac{2\nu^2 kT}{c^2},$$ and the approximation becomes better and better as $kT \gg h\nu$. The equivalent expresson per unit wavelength interval is $$B_{\lambda} \simeq \frac{2c ... 4 The heat you dissipate during a fever comes from chemical bonds inside your body. So you are actually loosing energy to the environment faster than you would if healthy, making you (in principle) weigh less. However, I'd like to stress that this effect is terribly small compared to everything else that's going on in a system as complex as the human body. ... 3 If your power supply is sourcing a positive current toward the ground, that corresponds to a flow of positive charge from the supply to ground. This is equivalent to a flow of negative charge from the ground to the power supply. In a real wire, only negative charges can flow, so the second thing will happen: electrons (which have a negative charge) will ... 3 Comments already hinted at this, but the simple answer is that when you wrote the average velocity as a function of temperature, you were using a non-relativistic approximation (which is valid for most "everyday" situations, but not at extreme temperatures). Furthermore, since the particles have a mean velocity \bar u, you can't simply set that equal to ... 2 The Young's modulus of steel doesn't change significantly between say 10ºC and 20ºC (I'm guessing this is roughly the range of temperature between morning and midday). So the stiffness of the steel won't be changing. However I would guess that the steel wire has a polymer binding it together, and possibly a polymer coating on the outside of the wire as ... 2 If the pressure in the entire pot of water is less than the vapor pressure of boiling water, and substantially equal to the ambient atmospheric pressure, then the entire pot of water will begin to vaporize, including its interior which vaporizes into bubbles. Bubbles form because the ambient pressure surrounding them is less than the vapor pressure of water ... 2 Take two wavelengths \lambda_1 < \lambda_2 and use the Planck's law for the spectral radiance.$$u(\lambda, T) = \frac{2hc^2}{\lambda^5}\frac{1}{e^\frac{hc}{\lambda k T} - 1}$$Then lets take the fraction of the two intensities$$\frac{u(\lambda_2, T)}{u(\lambda_1, T)} = \frac{\lambda_1^5}{\lambda_2^5} \frac{e^\frac{hc}{\lambda_2 k T} - ...

2

Air nearest the water is cooler than air farther above the water. As sound travels slower in cool air, if sound waves from warmer air enter the cooler layer they are refracted downward toward the ear of someone in a boat. If the water is calm, its flat surface allows sound waves to travel unobstructed and to reflect from the surface. Instead of ...

1

The higher the temperature, the more the peak wavelength of the radiation shifts towards higher frequencies. At higher and higher temperatures, the peak will be blue, then ultraviolet, before it shifts into X-rays and finally gamma rays. From this you would expect that at infinite temperature, the frequency would also be infinite. In reality of course, long ...

1

Yup of course. Temperature is a measurement of the kinetic energy present in a body. So if two bodies have same energy but different kinetic energies then it means they are at different temperatures. :) And yes heat can be transferred from one body to another body even they are at same temperatures or at same heat because heat is a form of energy which can ...

1

By using the spreadsheet at http://www.brucelindbloom.com/index.html?Calc.html I am getting Apple RGB values of (110,150,242), which on my screen is a purplish blue.

1

In addition to WhatRoughBeast's excellent answer let me also debunk the 'Thermite myth' that's so pervasive in 9/11 conspiratorial thinking. This misconception that burning Thermite could cause steel beams to melt is based on a poor comprehension of Heat Transfer. Adherents of the Thermite thesis start from the correct knowledge that burning Thermite ...

1

The total cooling power of a block of ice in water (or other water-miscible liquid) depends only on two things: the mass of the ice, and the initial temperature of the ice. The shape is irrelevant, except in that it changes how fast the ice absorbs heat from the water. If we assume that the cup of water and ice are insulated, and wait long enough for it all ...

1

I can't speak specifically for organic polymers, but I will try my best for polymers in general. Every bulk polymer is made of thousands polymer chains, which is made of many "mers" (Greek for unit). Consequently we have the name polymer . For many polymers at room temperature these chains are able to rotate, and because the bonds are not 180 degrees apart ...

1

This value will be temperature dependent. As long as the materials survive, the object will tend to that temperature over time. There is no "wind chill" for an object that is already at ambient temperature and for which evaporation is not relevant. But it will increase the rate of heat transfer when the temperature differs. So it will exactly cancel at ...

1

As BowlOfRed points out the incoming air has a certain temperature and the convective flow will tend to bring the temperature of the object towards the temperature of the incoming air. In the case where the incoming air was going very fast it gets heated through adiabatic compression before it reaches the object, so the incoming air is at higher temperature ...

1

Maxwell's distribution of velocities has been derived through classical arguments. It does not take into account relativistic effects. You don't need to evaluate anything to see that; just observe that it accepts arguments (velocities components) over the whole real line and does not have a cut-off at the speed of light. So it gives a non-zero probability ...

1

The gases shift substantially to lower atomic numbers, and you can find many academic references that give modeling references that show this. There is a lot of weather-based variation, particularly in the upper atmosphere densities, but this is extremely well-established science. If you want to know the fraction of Nitrogen at 200 km, you can totally find ...

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