A stopwatch is a handheld device used to measure time intervals with precision. It typically features a start, stop, and reset button, allowing users to track the duration of an event, such as a race or a cooking process. Stopwatches can display time in hours, minutes, seconds, and fractions of a second, making them useful in various fields, including sports and science. Modern stopwatches can be digital or analog. Digital stopwatches often have additional features like lap timing and memory functions, while analog stopwatches use a moving hand to indicate time. Both types are commonly used by athletes, coaches, and researchers to monitor performance and conduct experiments.