Day (d)
The day, symbol d, is the time it takes Earth to rotate once. A day is 24 hours or 86,400 seconds. Because Earth’s spin changes a little, days can vary, so leap seconds are sometimes added to atomic clocks. The day is a key part of human life, shaping calendars, routines, and events in all cultures. It is one of the most fundamental and widely recognized time units.
Minute (min)
The minute, symbol min, is 60 seconds. Its name comes from the Latin for “first small part.” Minutes have been used since ancient times when base-60 number systems shaped early timekeeping. Minutes are part of daily life—used in clocks, plans, and math. Although the SI system uses seconds, minutes are still important for daily and cultural needs, thereby linking science with everyday life.