# Thermal Conductivity Definition

1. Sep 8, 2008

### Kasper_NYC

Hi,

I have read that Thermal Conductivity means: “The thermal conductivity of a substance is the quantity of heat in cal/sec passing through a body 1 cm thick with a cross section of 1 sq. cm when the temperature difference between the hot and cold sides of the body is 1 deg. C.” http://www.lib.umich.edu/dentlib/Dental_tables/Thermcond.html [Broken]

Does it means also how fast a substance can increase or decrease its temperature when is in contact with a heater or colder fount? For example, will it means that in the case of the Alumina (recrystallized), that its index is 38.7 (mcal/s) / (cm^ C/ cm), 1 cubic centimeter will absorbs 0.0387 cal /second, having 1 square cm of surface in contact with the heat fount?

I am interested in to find the formula that lets to calculate how fast a given mass of substance warms up or colds down by second, in an ideal system (without losses of heat).

The other question is if “1 (cal/sec) / (cm2 C/cm) = 419 W/m K”; is 419 W/m K equivalent to 4.19 W/m K? (http://hyperphysics.phy-astr.gsu.edu/Hbase/tables/thrcn.html#c1)

Thanks a lot.

PS – I apologize for my English, I am learning it.

Last edited by a moderator: May 3, 2017
2. Sep 8, 2008