Which thermometer is the most accurate?

Of course, the temperature measured by mercury thermometer is more accurate.

The basic principle of mercury thermometer is that mercury expands when heated. Yes, the mercury column in the thermometer has risen in a certain direction.

So as to reach the indicated temperature or the indicated body temperature.

There are other reasons for choosing these two materials for thermometers: they are sensitive to the change of volume with temperature; In addition, they are not easy to solidify into solids at low temperatures and become gases at high temperatures.

This is the main reason for choosing mercury as thermometer medium.

When measuring body temperature, the mercury in the vacuole expands inward under the influence of body temperature, and it can be seen that the mercury rises from the neck to a certain position in the pipe string. When the mercury column and body temperature reach thermal equilibrium, the mercury column is constant.

The function of temperature measurement. After not using, the thermometer leaves the human body. Because the outside temperature is lower than the human body temperature, the mercury will shrink slowly when it is cold, and the watermark will be broken at the narrow neck, so that part of the mercury that has risen into the tube cannot return, and the height of the mercury column remains unchanged when it contacts the human body.