3 ms·
I looked it up. Actually wood had about twice the specific heat as aluminum. So I must revise my original comment to remove specific heat as a driving factor.
by iancmceachern 5y ago
I looked it up. Actually wood had about twice the specific heat as aluminum. So I must revise my original comment to remove specific heat as a driving factor. This leaves only thermal conductivity. A wood ladder would have more heat to give than an aluminum one, but it still is able to give it much slower, making it ok to touch for longer.
- kragen 5y agoAgreed. I'm surprised the difference in specific heat is so large! Maybe that's fairly humid wood? Because glucose is about 220 J/mol/K https://webbook.nist.gov/cgi/cbook.cgi?ID=C492626&Mask=2#Thermo-Condensed https://webbook.nist.gov/cgi/cbook.cgi?ID=C492626&Mask=2#The... and 180.2 g/mol https://en.wikipedia.org/wiki/Glucose https://en.wikipedia.org/wiki/Glucose, working out to 1.2 J/g/K, and aluminum is 24.2 J/mol/K and 27.0 g/mol, giving 0.90 J/g/K. My general rule is that everything is 1 J/g/K except water, which is 4.2. It's obviously not true, but almost always within a factor of 2, and 1 is an especially easy number to multiply and divide by.
- jholman 5y agoReading your first paragraph, I was thinking "water. the answer is always water", when it comes to estimating the properties of life-stuff vs everything-else-stuff within a factor of 2. Not obviously, of course, but it's just such a powerful heuristic. Reading your second paragraph, I see you're familiar with the principle, and added a good heuristic to my stockpile, thank you.
- kragen 5y agoHappy to share :]