The 12-hour clock

Time! This is something which structures our lives on a daily basis and even gives us a term of reference to events in our lives, e.g.

• School starts at 8am
• Soccer practice is at 3pm
• You ran the 100 m sprint in 16 seconds

But can you actually define what time is?

In simpler words time is "the measured or measurable period during which an action, process, or condition exists or continues", e.g. how long does it take you to brush your teeth? How long are your school holidays? What time does your soccer practice start?

In this course we will explore the different time clocks, how to convert between one and the other, various time units and then we will progress on to how to add and subtract units of time as well as how to calculate elapsed time. 

How to read / write the time using the 12-hour clock

Have you heard of the 12-hour clock? This clock provides one of the ways in which to read and write the time. As its name suggests, it works on a 12-hour basis - but there are 24 hours in one day so therefore the clock goes past the 12 o' clock number twice!

So essentially, the 24-hour day is divided into two, namely:

• AM: Ante meridiem. The easy way to remember what AM stands for is BEFORE midday / noon
• PM: Post meridiem. An easy way to differentiate PM from AM is that PM is AFTER, or POST midday

Watch the YouTube video below which explains this concept very clearly.

MooMooMath and Science. (2019). Difference between AM and PM (Standard YouTube licence)

Test your understanding of what has been covered so far by answering the questions in the short quiz below.