On Sun, Oct 19, 2014 at 7:05 AM, Craig Haynie <cchayniepub...@gmail.com> wrote:
"The temperature of a Pāhoehoe <http://en.wikipedia.org/wiki/ > Lava#P.C4.81hoehoe> lava flow can be estimated by observing its color. > The result agrees well with measured temperatures of lava flows at about > 1,000 to 1,200 °C (1,830 to 2,190 °F)." > > http://en.wikipedia.org/wiki/File:Pahoehoe_toe.jpg I assume the temperature should be estimated from the light patches in the lava flow, since the darker patches are areas of the surface that are starting to harden. The lighter portions match the color in the image Jed has been pointing to, making an estimate of 1000 to 1200 C seem reasonable [1]. The challenge with lava is that it is essentially a blackbody, as can be seen by the areas of the lava flow that have already cooled down. People are debating elsewhere in this thread whether the same heuristic for deriving temperature from color can be applied to something that isn't a blackbody (e.g., glass, or an alumina cylinder). I wonder if there is someone who can speak from professional experience on this question. Eric [1] http://en.wikipedia.org/wiki/Incandescence#mediaviewer/File:Incandescence_Color.jpg
