Why mercury is preffered in clinical as well as laboratory thermometer
Answers
Hey mate, here's your answer.
Most metals are good conductors of heat and they are solids at room temperature. Mercury is the only one in liquid state at room temperature. It's used in thermometers because it has high coefficient of expansion.It also has a high boiling point which makes it very suitable to measure higher temperatures.
1. It is very reflective, so it's easy to see and to read accurately.
2. It doesn't wet the glass, so you don't get inaccurate readings if the temperature is falling.
3. It is a metal, so it's a good conductor of heat. This means that it reacts quickly to changes of temperature.
4. It expands evenly with temperature, so a linear scale can be used with quite a high degree of accuracy.
5. There's a large range of temperature for which it is a liquid. However, it freezes at - 39 Celsius, so Mercury cannot be used below this temperature. It boils at 365 Celsius, which is high enough for most purposes.
Hope this helps.