Hot enough for you? I’ve been thinking about heat lately, and not just because of the nation’s mostly torrid weather.
We all can easily verify that hot air rises – when you change a light bulb near the ceiling of your living room, you find the air up there is warmer than it is near the floor. Another fact about heat rests on a simple experiment. If you rub your palms together you’ll feel some warmth. Then, if you bear down on your hands, pressing them together hard, you’ll create quite a bit of heat.
Early scientists tried to understand the basic facts of heat with general theories. One such theory stated that heat was something like a fluid. After all, it seemed that it could flow from warm bodies into cold ones, equalizing over time so that both were at the same temperature. It sometimes affected the size of the bodies it inhabited, for example making hot air take up more volume than cold air – creating the reason that hot air rises.
But heat was an odd substance in some ways. It had no mass, a fact verified by weighing a solid object, then heating it up, and finding it still weighed the same.
Benjamin Thompson was an early scientist who studied heat. Born in 1753 in Massachusetts, he later moved to continental Europe where he was ultimately named Count Rumford of the Holy Roman Empire in recognition of his scientific accomplishments.
Count Rumford is famous in the history of science for a heat experiment. Back in his day, it was known that boring (grinding) out cannons made for a great deal of heat.
Count Rumford immersed a cannon in a water bath, then ground out the hole as he measured the rise in temperature of the water. The change was so great the water actually boiled after two and a half hours of the heavy work.