Less common in the daily life of thermometer do you know?

Thermometer, it is the floorboard of the temperature measuring instrument, can accurate judgment and measuring temperature, content without solid, liquid, or gas, with the development of science and technology, there are many kinds of thermometer for us to choose, but these less common thermometer in daily life you know? LCD thermometer, according to its made of different formula of liquid crystal is different, its phase transition temperature is different, when the phase change, its optical properties will change, also makes them look changed color LCD. If the different phase transition temperature of the liquid crystal coating on a piece of paper, by the change of the liquid crystal color, you can know why temperature. The advantages of the thermometer reading is easy, while the disadvantage is accuracy, often used in ornamental aquarium, to indicate that the water temperature. The principle of the gas thermometer is under fixed pressure, small density of gas, a linear relationship with the size and temperature. Using the relationship of thermometer, known as the constant pressure gas thermometer. Under the fixed volume, small density of gas, a linear relationship with the pressure and temperature. Using the relationship of thermometer, it is called a constant volume gas thermometer. Besides, there are optical pyrometer. Object if the temperature is high enough to make a lot of visible light, can use to measure the amount of the thermal radiation to determine the temperature, the thermometer is the thermometer. The thermometer mainly by telescope equipped with a red filter and a group with a small bulbs, galvanometer and variable resistance of circuit is made. Before use, first establish the filament brightness corresponds to different temperature and the relationship between the reading on the galvanometer. When used the telescope was tested, adjust the resistance, make the brightness of the light bulb and the same object under test, then from galvanometer can read the temperature of the object under test.