What is the distinguishing feature of expansion type thermometer?

Expansion of the thermometer temperature measurement is based on the principle of expansion of objects when heated expansion type can be divided into liquid and solid expansion type two kinds, such as pressure type thermometer, resistance thermometer, thermocouple, radiant thermometer etc. There are many other special thermometer. In daily life we often use the thermometer, it makes use of the material on the principle of the heat from the cold. Inflation, said in a thermometer temperature material with liquid and solid, with metal and nonmetal. Such as the bimetallic thermometer is to use two pieces of thermal expansion coefficient of different pieces of metal, the working principle of thermal expansion is end, turns the pointer, the instrument will show should value. But we see most is the expansion of the liquid medium thermometer, its structure is commonly in sealed glass tube containing medium, medium materials generally have mercury, kerosene, alcohol and other liquids. In order to be able to see more clearly, alcohol, kerosene are often dyed red. In order to make the medium to low temperature is together and made into glass bulb at the end of the glass tubes of medium, make the most of the media in it. When temperature increases, the expansion of the medium thin tube along the rise, the higher the temperature, medium rises, the more and can be seen from a glass pipe scale, thus says the high and low temperature.