What do AM and PM mean on a clock? How do times on a 12-hour clock relate to the 24-hour format? The 12-hour clock is a time convention in which the hours of the day are divided into two periods: a.
Each period consists of hours numbered: . See Confusion at noon and midnight. The 24-hour clock is the convention of time keeping in which the day runs from midnight to . In formal writing, it is best to lowercase both a.
Midnight is considered 12:00:AM and 00:00:on the 24-hour time clock. Noon is considered 12:00:PM and 12:00:on the 24-hour time clock. To avoid confusion, the correct way to express o’clock is noon or midnight.
Tell students that the way to let people know if the clock says o’clock in the morning or o’clock at night is to say am or pm after the time.