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What do a.m. and p.m. stand for? |
Time & Numbers
The abbreviations a.m. and p.m. are used to help us tell time. There are 24 hours in a day, but if we were to see 24 numbers on an analog clock, the kind that we hang on our walls that are round and have hands that point to the numbers, the clock face would look really crowded!
To make counting time a little simpler, the day can be broken up into two groups. The first group starts at midnight (12:00) and goes to 11:59 in the morning. All of these times are labeled with a.m., which comes from a Latin phrase that means “before noon.” The second part of the day, from noon (12:00) to 11:59 at night, is labeled p.m., which means “after noon.”
Some places in the world don’t use a.m. and p.m. Hours after noon keep counting upward. You might see a weird time like 17:30, which is actually the same time as 5:30 p.m.!
If you’re curious, the actual Latin phrases that a.m. and p.m. stand for are “ante meridiem” and “post meridiem”.
A 24-Hour Clock
When you use a 24-hour clock, there is no a.m. or p.m. Instead the hour after 12:00 noon is called 13:00 (read “thirteen hundred” or even “13 o’clock”.) To go from 12-hour-clock time to 24-hour-clock time, you just add 12 hours to every p.m. time.
2:00 p.m. would be 14:00 because 2 + 12 = 14.
The time between midnight and 1:00 (a.m.) starts with “00”. 12:05 a.m. is 00:05 on the 24-hour clock.
What time do you normally eat dinner? What time would that be using a 24-hour clock?
What would your bedtime be using a 24-hour clock?
