Agent Training: Phase 2 - 24 hour time
Now that you have mastered recognising and writing the time in a 12 hour format, it's time to work out how to understand 24 hour time.
The advantage of the 24-hour clock is that it removes any possible confusion about a time (e.g. morning or night), by removing the need to use 'am' or 'pm'. 24 hour time is often referred to as "military time" as it us used by defence forces when referring to time.
In your first agent training, you reviewed how to write 12 hour times - 12:00am is midnight and 12:00 pm for noon.
In 24-hour time, 00:00 is midnight and 12:00 is noon.
When reading a time in 24 hour notation, you will see four numbers. Sometimes there is : between the first two numbers and the second two. The first two numbers represent the hour, the last two numbers represent the minutes.
For example - 14:30 = 14 hours and 30 minutes, or 2:30pm.
Many of the times look the same when written in 12 and 24 hour formats - just don't forget to add the 0 to make sure there are 4 numbers! To change between 12 and 24 hour times you simply add or subtract 12 hours as required!
It can be further summarised by the following rules:
When you need to convert to 24-hour time from 12-hour time:
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For times between 12:00 A.M. and 12:59 A.M., you subtract 12 hours.
Example- 12:15am is written as 00:15
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For times between 1:00 A.M. and 12:59 P.M., you do not need to add or subtract.
Example- 10:30am is written as 10:30
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If the time is between 1:00 P.M. and 11:59 P.M., you add 12 hours.
Example- 2:20pm is written as 14:20
So, based on the above, it works in reverse when changing 24-hour time to 12-hour time:
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For times between 00:00 and 00:59, you add 12 hours.
Example- 00:45 is written as 12:45 a.m.
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For times between 01:00 and 12:59, you do not need to add or subtract.
Example- 02:00 is written as 2:00a.m.
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If the time is between 13:00 and 23:59, subtract 12 hours.
Example- 14:00 is writen as 2:00pm.
Time conversion chart [image]. (2010). Retrieved from http://www.onlineconversion.com/date_12-
24_hour.htm
With your partner, think about how 24 and 12 hour times differ.
Where have you seen time written in this way?
Have a look at the following pictures.
Wilson's (2011) 24 hour time activity.
Wilson. (2011).
Wilson (2011)
Which way communicated the time the best? Why do you think this is so?
