Desiree McMahon/Demand Media

The 24-hour clock is the standard time-telling system in many countries and organizations, including the United States Armed Forces and most South American countries. Thus, teaching 24-hour time activities to kids is a great way to help them understand organization in other parts of the world. However, because of the widespread adoption of the 12-hour a.m./p.m. clock in the United States, many children never learn how to tell time on a 24-hour clock. Provide a worldly alternative to the 12-hour digital clock by teaching kids how to read a 24-hour clock digram.

Compare and Contrast

Set two clocks, one a 12-hour digital clock and one a 24-hour clock, to the same time in the morning. Set the clocks next to each other so that they may be compared side by side. This will give children a basic knowledge of what times on the 12-hour clock correspond to the times on a 24-hour clock.

Explain a 24-hour clock as an "extension" on a 12-hour clock, rather than as a completely different system. Explain that when a 12-hour clock reaches 12:59 p.m. and proceeds to 1:00 p.m., the 24-hour clock keeps going to 13:00 and onward.

Use a 24-Hour Clock Diagram

Teach kids that an easy-to-remember way to read the clock is that any time past 12:00, say 14:32, on a 24-hour clock, is in the afternoon. Setting up a 24-hour clock diagram that illustrates the passage of time throughout the day can help kids grasp this concept. In teaching 24-hour time activities with the diagram, you can show that the bigger the hour number is on the clock, the later it is in any given day. The exception to this is midnight, which a 24-hour clock indicates as either 00:00 (when describing the start of a new day) or 24:00 (when describing the end of the previous day). To explain that concept, you can teach kids that the lowest number of all zeroes is the start of a new day and the highest number, 24:00, is the very end of the day.

Do Math to Help

If the children have a basic understanding of addition and subtraction, teach them that they may subtract 12 from the hour of any time past 12:00 p.m. on the 24-hour clock diagram to find its 12-hour digital clock counterpart. For example, 15:34 minus 12 hours is 3:34 p.m. on a digital clock.

Teach 24-Hour Time Activities

Make a game out of the two clocks set up side by side. Cover the 12-hour digital clock with a piece of construction paper or fabric and have kids guess the time on the 12-hour clock by only looking at the 24-hour clock beside it. When they have a good grasp of the concept, cover the 24-hour clock and have the children guess its time based on the 12-hour clock.