In the Forensic Physics course I’m teaching this summer one of the things we study is post-mortem body cooling. We look particularly closely at two papers that estimate various factors involved in body cooling. In one such paper, the authors give cooling curves – plots of temperature difference ratio versus hours after death. The temperature difference ratio is given by

$R=\frac{T_{bt}-T_{et}}{T_{b0}-T_{et}}$

where $T_{bt}$ is the body temperature as measured at the site (brain, liver, and/or rectum), $T_{b0}$ is the ‘normal’ body temperature (98.6ºF on average), and $T_{et}$ is the temperature of the environment at the time the body temperature is taken.

But note that this does not seem to take into account fluctuations in environmental temperature. It seems like it would work just fine for a body found in a location with little day/night temperature variation (at that time). But what about cases in which there is a large swing in environmental temperature in a short period of time? For example, it dipped into the 50’s at my house last night but is supposed to get into the low 70’s today. Even moderate differences in $T_{et}$ will cause time estimates to be off by quite a bit.

Of course, I could just see about finding a paper that addresses this issue, but, always up for a challenge (and armed with the suggestion of a student), I’m looking to see if there’s a way to estimate it by extrapolation. The seed of an idea is gestating in my head and we’ll see if it grows into anything. But it is curious that this issue is not addressed in the article. How did this clear peer-review? In fact, there’s a major error in the article too. Honestly it is likely a typo, but one equation is missing a factor of 1/1000 that is necessary for the numbers to come out right. Again, how did this clear both peer-review and the editing process? If I so much as forget to dot an i I get nasty referee and editor comments (ok, that’s a slight exaggeration, but only slight).