# Cold Climates

1. Oct 30, 2005

### Pythagorean

I'm a physics major in Alaska, where it's not uncommon to have temperatures of -40.

Are there any interesting experiments or designs that I can do in my freetime that are convenient because of the cold weather?

I remember learning briefly about gradients being a source of power. If someone could give me a good keyword for that, I could better Google it (or look it up in my physics text books). Is the temp difference of -40 (outside) to 68 (inside my house) a large enough difference to even consider generating power (even if for fun).

2. Oct 30, 2005

### Tide

Please verify for us that mercury freezes at -38 F and measure the speed of sound! :)

3. Oct 30, 2005

### ZapperZ

Staff Emeritus
... or that warm water freezes faster than cold water. :)

Zz.

4. Oct 30, 2005

### PerennialII

Breaking things has typically the best success ratio in cold climate.

5. Oct 30, 2005

### BlueParrot

I didn't realise you were talking about Farenheit until I read you had 68 degrees indoors( Yes I have experienced outdoor temperatures close to -40 C )

6. Oct 30, 2005

### pallidin

Temperature gradients can most certainly be used as a "source of power" Thermocouples, and its cousin thermopiles, are an example of this.

7. Oct 30, 2005

### krab

-40c = -40f

8. Oct 31, 2005

### Pythagorean

thank you, knowing the name always make googling easier :P

9. Oct 31, 2005

### whozum

10. Oct 31, 2005

### cepheid

Staff Emeritus
Yup, just do the conversion:

1. Shift zero point to that of the Celsius scale

-40oF - 32oF = -72oF

2. Convert to Celsius degrees

-72oF * 5oC/9oF = (-72/9)*5 oC = -40oC

11. Nov 1, 2005

### Pieter Kuiper

12. Nov 1, 2005

### GENIERE

Might be an ideal application for a Sterling Engine.

13. Nov 2, 2005

### krab

Sure, but I hope you don't imagine that this gives energy for free. A large temperature difference makes an engine more efficient, but you still have to supply the energy. In this case, your furnace will be providing the energy, as the operation of the engine will take heat out of your house.

14. Nov 15, 2005

### Pythagorean

Absolutely not! I'm willing to put energy into the experiment. I've been salvaging electronics from the dump, and usually, the components are good (I ignore the integrated circuits, aka circuitboards.)

I just have no idea how you would be able to even get a potential difference. What sucks is I did a lab where we did this with two wires (one silver and one copper), and a pot of boiling water as the hot end. The wires were somehow wired through a part of the pot with boiling so that the wires will conduct heat, and the ratio between their heat conductivity will generate a voltage.

I'm really shaky on this; I've looked it up, but I haven't nailed the right keyword yet. I can't even find it in my physics book, usind the index, thumbing through pages. As a matter of fact, I save my lab reports, and I can't find the particular lab I'm thinking of. It's almost as if I've dreamed it up! But I remember measuring a voltage across two different materials (both heat and electricity conductors) and there was a pot of boiling water involved!

15. Nov 15, 2005

### Pieter Kuiper

The keyword are Seebeck-effect, or thermoelectric effect, or Peltier effect (when you run it the other way around).

(It does not depend on the thermal conductivity.)

Last edited: Nov 15, 2005
16. Nov 15, 2005

### Pythagorean

Last edited by a moderator: Apr 21, 2017