NewScientist.com has a brief article today about the work done by Nicholas Kotov at the University of Michigan in developing a nanoscale spring thermometer. Traditional spring thermometers, also known as bimetal thermometers, consist of two thin metallic layers, usually iron and copper joined together to make a strip that is often formed into a coil. Because the two metals have different constants of expansion, the coil will expand if heated and contract when cooled. The change can measured and calibrated allowing the coil to act as a thermometer. Unfortunately these types of thermometers are notoriously insensitive, sometimes exhibiting errors of up to ±10 °C. Kotov’s nanoscale version functions in much the same way but is accurate to ±3 °C over the range of 20 – 80 °C.