👉 Mercury fluid, also known as thermometer fluid or glass thermometer fluid, is a liquid typically composed of mercury and sometimes other additives like alcohol or glycerin. It is used in thermometers to measure temperature accurately due to mercury's unique properties: it has a high density, which allows it to fill small spaces precisely, and it expands predictably with temperature changes. This fluid's low viscosity and high thermal conductivity make it ideal for transferring heat efficiently from the temperature sensing element to the measurement device. However, due to mercury's toxicity and environmental hazards, its use is now regulated in many regions, and alternatives like alcohol-based fluids are often preferred.
