Snowmelt Physics

Back in February (oh, that dreadful month!), when it seemed like the temperature was never able to get above freezing, I mentioned to my husband that even though the snow couldn’t be melting, when I measured the snowpack it was an inch or so lower than the previous day.  (Yes, I was maniacally measuring the snow.  I like counting things.)

Common Household Husband said, “The snow is melting.  It melts according to the formula PV=nrt.”

“Huh?  Are you quoting the formula for the present value of money?”  I reached into the dim recesses of my mind, recalling that PV means “present value” and the formula probably included an “r” in there somewhere to represent the interest rate.  But “n” and “t”?

The uncommonly scientific Husband replied, “No.  PV=nRT.  It’s Frank’s Law.”

Yeah right.  I was believing the formula part, but when he named it Frank, my skepticism skyrocketed faster than the temperature rise of a gas under pressure.

“Pressure times volume equals n times R times temperature.  The snow on top pushes down on the snow underneath, thereby increasing the pressure at the bottom of the snowpack.  Since it can’t expand in volume, the temperature increases.  So the snow melts at the bottom of the snowpack.”

Thus speaks the scientist.  Except we should keep in mind that he is a biologist, not a physicist.  Frank’s Law, indeed.  It’s great hanging out with scientists.  They have a different law for everything.

In any case, whether it’s Frank’s or Bob’s or Joe’s law, we hold hope of actually seeing the grass sometime soon.