The Scientific American article A Simple Twist of Thermodynamics Could Lead to Greener Refrigeration by Sophie Bushwick (1/21/2020) reports about the Science paper Torsional refrigeration by twisted, coiled, and supercoiled fibers by Run Wang et. el. (10/11/2019), which is behind a paywall (the graph here is from that paper). From the Scientific American article:
For another example, picture a rubber band, which is made up of a bundle of fibers. In the early 19th century, researchers found that pulling one makes it feel warmer. This effect happens because stretching the rubber band aligns the fibers more neatly, with less disorder. For this decrease in entropy to occur, the object has to pull in energy, in the form of heat, from its surroundings. When the tension is released, the entropy increases again, and the band cools down.
From the abstract of the Science paper:
Refrigerators using entropy changes during cycles of stretching or hydrostatic compression of a solid are possible alternatives to the vapor-compression fridges found in homes. We show that high cooling results from twist changes for twisted, coiled, or supercoiled fibers, including those of natural rubber, nickel titanium, and polyethylene fishing line.
The Scientific American article has a couple of interesting animations. The Science paper is technical. I’m not sure how to use any of this in a math classroom. I’m posting this because it is really interesting.
