Mechanical Watch
Mechanical watches operate without batteries through an intricate system of purely mechanical components centered around a mainspring that stores energy when wound. The article explains how a torsion spring contained in a barrel serves as the power source, with the spring's desire to expand driving the watch's timekeeping mechanism through a series of interconnected parts. The author breaks down the watch movement's seven major elements that work together to keep accurate time and rotate the watch hands at the correct pace.