Thermometer 100 degree is specified according to the water temperature.

Thermometer 100 degree is based on the temperature when water boils. At standard atmospheric pressure, the boiling point of water is 100℃, which is also the scale of 100 degrees on the thermometer.

The boiling point of water refers to the temperature required for water to change from liquid to gas. When the water temperature reaches the boiling point, water molecules will evaporate from the liquid surface to form water vapor. This temperature point is determined by the physical and chemical properties of water, and the boiling point of water will be different at different altitudes and pressures.

In order to determine the boiling point of water, scientists used a tool called thermometer to measure the temperature. In the laboratory, scientists use highly accurate instruments to measure the boiling point of water to ensure its accuracy. These instruments can measure small temperature changes and record the results to several decimal places.

Besides water, scientists also use other substances to determine the scale of thermometers, such as freezing point and melting point. Freezing point refers to the temperature required for water to change from liquid to solid, and melting point refers to the temperature required for matter to change from solid to liquid. These temperature points are determined according to the physical and chemical properties of substances and can be used to determine the scale of thermometers.

Type of thermometer:

1. Rotating thermometer: The rotating thermometer is made of curled bimetal. When the temperature changes, the bimetal will rotate, thus driving the pointer to rotate on the dial to indicate the temperature.

2. Semiconductor thermometer: Semiconductor thermometer is made by using the characteristic that the resistance of semiconductor changes with temperature. It is usually made of semiconductor materials such as carbon and germanium, and has high accuracy and sensitivity.

3. Thermocouple thermometer: Thermocouple thermometer is made by thermoelectric effect. It is made of two different metal wires welded together. When the temperature changes, an electromotive force will be generated between the two wires, thus indicating the temperature.

4. Optical pyrometer: Optical pyrometer uses infrared radiation emitted by objects to measure temperature. Usually used for high temperature measurement, such as smelting, ceramics and other industries.

5. Liquid crystal thermometer: Liquid crystal thermometer is made by using the phase transition temperature characteristics of liquid crystal. When the temperature changes, the color or transparency of the liquid crystal will change, indicating the temperature.