Place it in an environment with a large temperature difference from the room temperature for a period of time, and observe that the pointer of the thermometer will have obvious changes. For example: in the refrigerator, due to the slow change of the mechanical movement, the slow change will take longer. Due to the different air pressure in different places, the display position of the pointer is also different. In some areas, the pointer of extremely low air pressure may even point below the range or even exceed the range. You can take a deep breath at the small hole at the bottom of the back of the product, and you can clearly see that the humidity changes upward and then drops again after a period of time. This product is used to measure parameters such as ambient temperature, humidity and air pressure, and accurately predict future weather changes based on changes in ambient temperature, humidity and air pressure. Owning it is like owning an outdoor barometer, hygrometer and weather station. Easy to use: easy to install, no plug or battery required, can be hung on the wall or placed on the countertop, very suitable for indoor and outdoor wall decoration. It can be used both indoors and outdoors.