How does a BBQ thermometer work?
TECHNOLOGY: Max Bamford Campbell from Churchill Park School asked this question.
Thermometers work very many ways and it really depends on the type you have. The standard ones work on mercury which responds to temperature by expanding and rising up the glass pipe. However, no one likes mercury near their food, it’s rather poisonous and glass cracks under heat like you find in a BBQ, so that would be a mess.
A BBQ thermometer, at least the simple ones, use a very thin strip of metal in place of the mercury. When it is exposed to the heat in the BBQ, the metal expands. A lot! That expansion triggers motion, which in turn can move the temperature dial to tell you how hot it is in the BBQ. There are other ways to record temperature, but this is one of the simplest and most common, as well as the lowest cost, so you are likely to find that type on many BBQs.
Distinguished Professor Geoff Chase from the University of Canterbury answered this question. He is a Fellow of Royal Society Te Apārangi, which means he’s one of the top experts in his field of engineering.
For more information on our expert, visit his profile: Geoff Chase