Full Form of AM and PM - Definition of AM, PM and Uses
Both AM and PM are Latin words that are used in the 12-hour clock system representing Before and After Noon. They are also written as A.M. and P.M.
AM is Anti Meridiem which means "before midday"
PM is Post Meridiem, which means "after midday".
Converting 12-hour to 24-hour clock
You have to subtract 12 hours starting from the first hour of the day (12:00 A.M. or midnight to 12:59 A.M.):
- 12:00 AM = 0:00
- 12:15 AM = 0:15
The hours and minutes remain the same from 1:00 AM to 12:59 PM:
- 9:00 AM = 9:00
- 12:59 PM = 12:59
Add 12 hours For times between 1:00 PM to 11:59 PM:
- 3:17 PM = 15:17
- 11:59 PM = 23:59.
12-Hour Clock Use
The use of the 12-hour clock can be traced as far back as ancient Egypt and Mesopotamia. In the tomb of Pharaoh Amenhotep I, there were found both, an Egyptian sundial for daytime use and an Egyptian water clock for night-time use. These clocks divided their respective times of use into 12 hours each dating to c. 1500 BC.
Also, the Romans divided the day into 12 equal hours and the night was divided into four watches. Thus they too used the 12-hour clock.
In the present day, there are 18 countries using the 12-hour clock: India, Ireland, Jordan, Malaysia, Mexico, New Zealand, Australia, Bangladesh, Canada, Colombia, Egypt, El Salvador, Honduras, Nicaragua, Pakistan, Philippines, Saudi Arabia and U.S. (although the military uses the 24-hour clock).
Uses of AM and PM
In the 12- hour time zone, both AM and PM are used to differentiate the time in day and night. The 24 hours of the day are divided by them into two time zones that last 12 hours each. The duration of the first 12-hours last from midnight to noon and is designated by am. From noon to midnight, is the second 12-hour duration designated by pm. Therefore, the numbers from 1- 12 are all followed by am or pm and are used to identify all the 24 hours of the 12-hour clock system.
For instance: Just saying "I will come at 6 O'clock" might confuse you. As you don't know whether it is in the morning or in the evening. But, if it is said, " I will come at 6 a.m." then it is certain that the person will come in the morning.
AM: The time from midnight to noon is represented. (12:00 AM to 11:59 AM). For instance: When you say you have to go college at 11 AM, it means 11 O'clock in the morning.
PM: The time from noon to just before midnight is presented. (12 Pm to 11:59 PM). For instance: When you say that you have to take dinner at 11 PM, it means 11 O'clock in the night.
You must keep in mind that the terms 12 a.m. and 12 p.m. often cause confusion, and they are not technically correct. Therefore, you are advised to use 12 noon instead of 12pm and 12 midnight instead of 12 am. The airlines and insurance companies, to avoid the confusion, use 12:01 am to mark the beginning of an event which begins with the day and 11:59 pm to mark the end of an event which ends with a day.
Related Questions
1). How can I remember 12 AM and PM?
The key to remembering 12 AM and PM is to understand the order of hours. There are 12 hours in a day, so the first hour is 12 AM and the last hour is 12 PM.
A better way to remember this would be that it's easier to remember when you think about how many hours there are in a day. There are 24 hours in a day, so the first hour is 1 AM and the last hour is 11 PM.
It is quite easy to remember the difference between AM and PM by using the acronym "A.M." which stands for "ante meridiem" or before noon, and "P.M." which stands for "post meridiem" or after noon.
So if you’re wondering what time it is in the morning, it would be A.M., and if you’re wondering what time it is in the evening, it would be P.M.
2). Which countries use 12-hour time?
There are two ways to tell the time in 12-hour format. One way is to say "twelve o'clock" instead of "twelve hundred hours." The other way is to use A.M. and P.M., which stands for "ante meridiem" and "post meridiem," respectively.
The 12-hour time system is used by a number of countries around the world. Some of these countries are Canada, India, Bangladesh, and Nepal.
Which countries use 12-hour time? - Canada, India, Bangladesh, and Nepal.
3). Is 12 am light or dark?
Some people say that 12 am is light and some people say that it is dark.
There is an ongoing debate over whether 12 AM is light or dark. Some people believe that it is a bright time of day while others argue that it is a time where people naturally feel more tired and therefore, it has to be dark.
The time of day can be seen as either light or dark.
4). Why is 12 am called midnight?
The word "midnight" is derived from the Old English words "mið" and "midde", which mean "middle of the night."
The term was originally used to refer to the time at which a person would go to bed in order to get an uninterrupted sleep. The term gradually became associated with the end of a day, and eventually came to be synonymous with 12 am.
5). When was 24 hour time invented?
The first time the term "twenty-four hours" was used was in 1793. It was a French mathematician named Jean-Baptiste Joseph Delambre who came up with the idea.
He published a book called The History of Measurement where he described the 24 hour clock and how it would be used to measure time.
This system is commonly used today and is considered to be more accurate than the 12 hour system.
