It's likely you're thinking of a thermometer. Thermometers are instruments used to measure temperature. Here's what you need to know about the metals used in them:
* Traditional Liquid-in-Glass Thermometers: These thermometers use a liquid, usually mercury or alcohol, to measure temperature. The liquid expands as the temperature increases, moving up a calibrated glass tube. While mercury is very accurate, it's toxic, so alcohol is often used as a safer alternative.
* Digital Thermometers: These thermometers use thermistors or thermocouples to measure temperature.
* Thermistors: These are made of materials like nickel or manganese, whose electrical resistance changes significantly with temperature.
* Thermocouples: These are made of two different metals, like copper and constantan (an alloy of copper and nickel), which produce a small voltage when there's a temperature difference between them.
So, the metals used in thermometers depend on the type of thermometer:
* Liquid-in-Glass: Mercury or alcohol
* Digital: Thermistors (nickel, manganese, etc.) or thermocouples (copper, constantan, etc.)
