The function of glass tube thermometer

　　Because the expansion coefficient of the temperature measuring medium is different from the boiling point and freezing point, our common glass tube thermometers are: kerosene thermometer, mercury thermometer, and red fountain pen thermometer.

　　Its advantages are simple structure, easy use, relatively high measurement accuracy and low price.

　　The disadvantage is that the upper and lower limits and accuracy of the measurement are limited by the quality of the glass and the properties of the temperature measuring medium. It cannot be transmitted remotely and is fragile.