Observe the thermometer carefully and talk about its structure and principle.

Observe the thermometer carefully. The structure and principle of thermometer are as follows.

I. Structure of Thermometer

The thermometer consists of a glass shell, liquid bubbles (mercury, kerosene and alcohol), a capillary tube and a calibration group.

Second, the working principle of thermometer

According to different uses, a variety of thermometers are designed and manufactured. The basis of its design is: using the phenomenon that solids, liquids and gases expand when heated and contract when cooled under the influence of temperature; Under the condition of constant volume, the pressure of gas (or steam) changes with different temperatures; The role of thermoelectric effect; Resistance varies with temperature; The influence of thermal radiation, etc.

Generally speaking, any physical property of all substances can be used to mark the temperature and make a thermometer as long as it changes monotonously and significantly with the change of temperature.