How do modern barometers differ from old mercury barometers?

Modern barometers differ from old mercury barometers primarily in that they utilize digital sensors or aneroid mechanisms instead of mercury. This advancement in technology offers several advantages, such as improved safety and portability. Mercury barometers require careful handling of mercury—a toxic substance—and are often bulky due to the need for a long glass tube to measure atmospheric pressure. In contrast, aneroid barometers use a metal diaphragm that expands and contracts with changes in pressure, allowing for a more compact design. Digital barometers take this further by providing real-time pressure readings electronically, often with additional features such as temperature or altitude measurement. Thus, the transition from mercury to digital or aneroid mechanisms reflects a significant evolution in design and functionality in pressure measurement devices.