The Second is a unit of time in the International System of Units (SI). It is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom. This precise definition allows for accurate timekeeping and synchronization across various scientific and technological applications. The Second is commonly used in everyday life to measure time, such as in clocks and timers. It is part of larger time units, including minutes and hours, where 60 seconds make up one minute and 3,600 seconds make up one hour.