What is in those tiny novelty thermometers?

You know the ones on keyrings or fridge magnets and other cheap stuff?

I have one on a magnet, it is surprisingly perfectly accurate. It has a red liquid inside, obviously not mercury.

Usually alcohol. The red is dye.


And in glass thermometers with silver liquid, the liquid nowadays is galinstan.

Huh. I just learned a new word! Thanks! :slight_smile:

“The marketing name is a portmanteau of gallium, indium, and stannum (Latin for “tin”).”