# Questions tagged [heat-conduction]

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### Calculating the temperature of flowing gas in copper tube

A copper coil is immersed in a water bath. The water bath provides heat to heat the nitrogen gas when it passes through the copper coil. Nitrogen gas at room temperature is passed through the copper ...
596 views

### How do I convert $W/(mK)$, $W/m^2$ and $W/(m^2K)$ to the same “dimensionality” and unit?

How do I convert $W/(mK)$, $W/m^2$ and $W/(m^2K)$ to the same "dimensionality" and unit? $W/(mK)$ is thermal conductivity. $W/m^2$ is heat flow density related to one unit. $W/(m^2K)$ is the ...
3k views

### Why doesn't a mercury thermometer follow the rules of volume dilatation?

let's consider a classic mercury thermometer. I do not understand why it does not behave like a "normal" thermometer which exploits volume dilatation. In a normal thermometer, I'd say that ...
144 views

A few days ago, I came up with this paradoxical conundrum: Let's say we have a gas enclosed in a container. Supplying heat to it will cause an increase in the (magnitude of?) vibration of gas ...
35 views

### Diffusion equation in terms of heat equation

I am solving a problem which goes like this: Solve the diffusion equation:$$\frac{\partial u}{\partial t}=\frac{\partial^{2} u}{\partial x^{2}}$$ for $t>0$ and $x \in > \mathbb{R}$, with ...
24 views

### Condensation of saturated vapor on subcooled droplet

Consider the process of condensation of vapor on falling subcooled droplet in the stagnant saturated vapor (neglect the vapor drag on droplet). What can be said about the relation between the droplet ...
2k views

### Heating cup in microwave?

I heated my milk cup in the microwave today and noticed that the cup was hot but not the handle. Even if I heat it too much , cups handle temperature remains the same. How is that possible?
572 views

### Calculating rate of heat loss through conduction and radiation

Calculate the rate at which a hollow cylinder with a heating element inside will lose heat, specifically through both conduction and radiation. My goal is to find the temperature inside this cylinder....
50 views

### Which heat capacity is used in the heat equation?

The heat equation is often written as $\frac{\partial T}{\partial t} = \frac{\kappa}{c} \nabla^2T$ where $\kappa$ is the thermal conductivity and $c$ is a heat capacity per volume. I often see $c$ ...
158 views

### Does a crushed ice cube and a regular ice cube have different potential energies?

For a question on an heat transfer experiment on melting ice cubes in water and measuring the temperature decrease in water, there was a question that asked: Suggest the effect, if any, of crushing ...
34 views

### Best color for pool cover [closed]

I couldn't find a stack* forum for pools, so I hope this is the next best place to post. I have an 18 foot diameter above ground pool in the north west, and I don't like the pool cover that came with ...
42 views

### Heat absorbed from a reservoir by a moving object [closed]

Imagine two bodies, say a body A with an infinite heat capacity(reservoir) and the another body B with some finite heat capacity($C = \alpha \ T_{B}(t)$). They come into direct contact with each ...
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### Why did my water boil “differently” this time?

Yesterday, I put a pot of water on the stove and set it to boil to make some pasta. I have done this many times but this time the boiling was qualitatively different than normal. Why would it be ...
4k views

### If steam and water, both at 100 °C, were exposed to a person's skin for a small time interval, which would result in a more severe burn?

Imagine that you had two boxes with of steam and water of equal mass, both at $100~^\circ\rm C$, and you decide to expose your left land to the steam and your right to the water for a short period of ...
68 views

### How do I set up the differential equations for the finite length iron stick heat diffusion?

Consider an iron cylinder. The heat doesn't go through the cylinder surface, but at the circular cross-section in the endpoints. The temperature of the surroundings is $15\ \mathrm{^\circ C}$. The ...
37 views

### Heat transfer from air (at ambient temp.) to a liquid in an open container [closed]

I’m designing a bath which should keep the temperature of the liquid inside (transformer oil) at a constant temperature (approx. 20 °C). I have calculated the amount of energy needed to heat up the ...
83 views

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### Calculating heat loss to surroundings from a cube suspended in air?

If you have a cube that is suspended in the middle of the air, how would you calculate the heat loss to its surroundings? For this example, I am assuming the following: Dimensions: 1m×1m×1m ...
106 views

### Rate of conductive heat transfer at a boundary between two different materials

I have one block of material 1, and one block of material 2. They are in contact with each other, sharing an interface of area A. Material 1 behaves as a lumped capacitance, with temperature T1(t). ...
57 views

### What is thermal conduction fundamentally?

Is conduction at the atomic level simply electromagnetic energy (photon) transfer, coupled with momentum transferred during collisions? Can conduction be summed up as thermal radiation + momentum ...