Both barometers and pressure gauges are used to measure air pressure. These devices have been used for many years. As a positive result of the development of modern technology, today, we have much more advanced equipment to measure air pressure than simple devices with very similar working principles. Even though these two devices have the same purpose, they differ in several properties and designs:

　　The purpose and characteristics of Air manometer:

　　Air manometer is used to measure air pressure, but it is used more frequently in meteorology and other fields and can make weather forecasts more accurately. The barometer is very useful for weather forecasting because it uses changes in atmospheric pressure to predict the weather. There are two types of barometers: mercury barometers and aneroid barometers. The aneroid barometer is digital and is a modern version of the device. The mercury barometer is still in use and is the earliest version of the device. As early as 1643, Evangelista Torricelli designed the first barometer, which consisted of a simple tall glass tube filled with mercury. How does the barometer work? According to changes in atmospheric pressure, the height of the mercury column also changes. Due to this change, the pressure used by the mercury column will be equal to the external atmospheric pressure applied to the surface of the test tube container. Although many users are increasingly using mercury barometers or aneroid barometers, mercury barometers are still in use. After all, the use of mercury is dangerous, and mercury should be avoided as much as possible.