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Q & A: thermal conductivity of ancient bronze

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Most recent answer: 07/10/2015
Q:
I am researching into ancient Egyptian Hairdressing, and the tools used.There are many that believe a certain tool made of Bronze was used as a curling tong. I have my reservations due to the size, shape of the tool, espcially as the items found never have any "handles" attached to the ends. Which would be needed to operate the supposed tongs.Therefore, I need to assertain if Bronze is a good conductor of heat, and if the handles of these tools would have been needed, if half of the tool was heated in the fire or hot ashes?If the item is made of Steel or Iron would the tongs need protective handles also, to guard from the heat?Hope you can shed some light and finally uncover half the mystery!Many thanks Fil
- Fil Salamone (age 43)
Surrey, England
A:

That's a very interesting question. We can estimate the thermal conductivity of a room temperature metal pretty well just by knowing the electrical conductivity, since the same electrons that carry the current are also mostly responsible for carrying heat. That's called the Wiedemann-Franz law ().

Here's a site that gives electrical conductivities of various metals.   You can see that some, e.g. stainless steel, are far lower than copper, around 2.5% as conductive. That's why stainless cooking pots can often get away with using stainless handles. I guess a curling tong could also work that way.

The conductivities of various bronzes, however, are all over the place. Some are about half as conductive as copper but others are less than 10% as conductive.  We don't know what bronze was used for these alleged curling tongs. So it's hard to know if anybody could have handled them.

Mike W.


(published on 07/10/2015)

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