* Mercury is a liquid metal that expands and contracts significantly with changes in temperature. It's been used in thermometers for centuries due to its predictable expansion and high boiling point. However, mercury is toxic and poses environmental risks, so its use in thermometers is now being phased out.
* Alcohol (typically colored with dye) is another common working fluid in thermometers. It has a lower freezing point than mercury, making it suitable for measuring lower temperatures.
While minerals like quartz can be used in certain types of specialized thermometers (e.g., quartz crystal thermometers), they are not the typical materials used in everyday thermometers.
