# Simple simple question

1. Mar 25, 2006

### _BaBy_PhAt_

Hi guys,

I'm doing a physics science fair, and I was just wondering if you guys know any cooling laws related speifically to surface area.

You see, for my science fair, I got three jars that had the same volume, but different surface areas. Then I filled them with hot water to see which one could come to room temperature fastest.

I need a law that I was supposedly "verifying" for my experiment.
I'd really appreciate any information.

Thanks!

2. Mar 25, 2006

### chroot

Staff Emeritus
You're looking for Newton's law of cooling:

http://en.wikipedia.org/wiki/Newton's_law_of_cooling

Heat conduction (energy per unit time) is linearly proportional to the surface area.

- Warren

3. Mar 25, 2006

### _BaBy_PhAt_

hmm.. I don't kno.. isn't Newton's law about the difference in temperatures between the two things? I need something that deals with surface area and heat loss.

Am I right, or am I just confused?

4. Mar 25, 2006

### chroot

Staff Emeritus
Look at the equation. A is the area. As I said, the heat conduction varies linearly with the area.

- Warren

5. Mar 25, 2006

### Integral

Staff Emeritus
You are correct in that Newton's law deals with a difference in temperature. It gives the energy transfer between objects of different temperature, but there is more to it then just temperature.

The temperature of a match is about the same as that of a bonfire (both are burning wood) but the difference in the amount of heat transferred by the 2 sources is huge. Newton's law assumes that the key factor in the difference is the surface area of the 2 sources.