An aneroid barometer is a device used to measure atmospheric pressure without the use of liquid. It consists of a sealed metal chamber that expands or contracts with changes in air pressure. This movement is translated into a reading on a dial, allowing users to monitor weather changes. These barometers are commonly used in weather forecasting and altitude measurement. Unlike traditional mercury barometers, aneroid barometers are portable and safer, making them popular for outdoor activities like hiking and sailing. They provide valuable information about changing weather patterns and can help predict storms or fair weather.