The snow is, in fact, melting—my back yard is down to about 18” of the compressed stuff—but it just started snowing again so who knows?! The weather forecasters tell us this has been the 3rd snowiest year on record in Vermont and if we get “just” another 20”, we’ll break the record set in 1970-71! Regardless, as we mark the Vernal Equinox, the sun is undeniably higher in the sky for longer each day. Solar heating is a powerful force not to be trifled with and it affords many fine opportunities to think about being warm and—when it is not shining—cold!
“Thinking Thermally” (as I call it) is the art of being somewhat of a thermal Sherlock Holmes; making ourselves aware of our thermal surroundings and, if we are skilled and lucky, figuring out why a thermal pattern appears the way it does.
Thinking Thermally is nothing new of course. As a child, I clearly remember my mother pouring hot water over the stubborn lid of a jar to loosen it up. A version of the same trick is used by many machinists as they heat a bearing to fit it on a shaft, or heat a nut to loosen it when it is stuck on a bolt.
Thinking Thermally is just part of what we do, almost unconsciously, as thermographers. Many electrical thermographers have found a hot spot and then noticed the discoloration that often accompanies abnormal heating. While I don’t know many professional cooks who use thermal imaging, they do use this relationship characteristic of temperature and color when they “brown” butter by heating it to various temperatures.
Moisture changes state between solid, liquid or gas at terrestrial temperatures. Each change of state of moisture is a great indicator of temperature and changes in temperature. Snow, frost and condensation often outline various thermal patterns: from the melt patterns on a roof or the hood of a car to the hazardous re-freezing of meltwater on the roads and sidewalks. And radiational cooling is just as powerful as solar heating! The full moon this week stunningly gleamed from a clear sky and, as expected with no clouds to hold the heat in, temperatures dropped below zero. And one more indicator of temperature change? Birds! The birds know all about temperature. I watched a Red-Winged Blackbird singing its spring song high in a tree, the first place the rising sun warmed.
We can even tell the compass direction by observing how snow melts. The sun, at least in the Northern Hemisphere, quickly points us toward the south in one way or another. Building thermographers know, too, they must be wary of the morning sun on the inside of a building’s east walls, while in the afternoon and early evening it is the west walls that are worrisome.
Last, but not least, Thinking Thermally can have its sweet rewards, too! The production of Vermont’s most famous crop, maple syrup, is dependent on nights falling below freezing, accompanied by sunny days above freezing. With these conditions, the sap in the trees rises from the roots to drip out the “tap” the sugar maker makes in the bark. The hard work of collecting the sap in buckets has been reduced by the use of plastic tubing and gravity, but reducing the forty gallons of sap to obtain one gallon of syrup still requires a great deal of energy—mostly supplied by scrub and dead trees cut out of the sugar woods last fall.
Wherever you are today and whatever your weather, I hope you have fun Thinking Thermally. What we can learn practicing these skills will serve us well when we pick up the thermal imager and head back to “real” work!
John Snell—The Snell Group, a Fluke Thermal Imaging Blog content partner