Time
Time is a way of measuring how long something lasts, how long it takes to do something or how long before things start or come to an end.
Measuring time
We measure out our days in hours, minutes and seconds. This helps us to organise all the time we have in one day.
There are:
There are:
- 60 seconds in 1 minute
- 60 minutes in 1 hour
- 24 hours in 1 day
We organise our days into weeks, months and years.
There are:
There are:
- 7 days in 1 week
- 28 to 31 days in 1 month
- 12 months in 1 year
- 365 days in 1 year
Numbers of days in each monthThere are 31 days in most months except: April, June, September and November, which all have 30 days, and February which usually has 28 days but has 29 every fourth year (called a leap year).
We use a rhyme to help us remember how many days there are in each month:
Thirty days hath September,
April, June and November;
February has twenty eight alone.
All the rest have thirty-one,
Except in Leap Year, that's the time
When February's Days are twenty-nine.
The units of measurement we use to measure time have been created over many years to help us to understand the seasons of the year and the amount of light and dark we have everyday.
We use a rhyme to help us remember how many days there are in each month:
Thirty days hath September,
April, June and November;
February has twenty eight alone.
All the rest have thirty-one,
Except in Leap Year, that's the time
When February's Days are twenty-nine.
The units of measurement we use to measure time have been created over many years to help us to understand the seasons of the year and the amount of light and dark we have everyday.
Analogue Time
There are 24 hours in one day, but the day can be measured by splitting it into two halves.
The first 12 hours of the day - from midnight to midday - are called AM, and the next twelve hours - from midday to midnight - are called PM.
When writing down times, morning times end in 'AM' and afternoon times end in 'PM'. This is called analogue time.
AM or PM?
With analogue time, the only way we know the right time of day is by adding AM or PM next to the time so we know if it's a morning or an afternoon. This is important because there is an 'AM' and also a 'PM' for every time of the day. For example, at 8.30am you are probably on your way to school, but at 8.30pm you are probably on your way to bed!
The first 12 hours of the day - from midnight to midday - are called AM, and the next twelve hours - from midday to midnight - are called PM.
When writing down times, morning times end in 'AM' and afternoon times end in 'PM'. This is called analogue time.
AM or PM?
With analogue time, the only way we know the right time of day is by adding AM or PM next to the time so we know if it's a morning or an afternoon. This is important because there is an 'AM' and also a 'PM' for every time of the day. For example, at 8.30am you are probably on your way to school, but at 8.30pm you are probably on your way to bed!
Digital Time
Digital time doesn't break up the 24 hours of a day into two halves, and digital time doesn't use AM or PM. Instead, it counts each of the 24 hours in the day.
7am is written as 07:00. 12pm (midday) is written as 12:00. In the afternoon, the clock numbers continue to increase, so that 1pm becomes 13:00, and 2pm becomes 14:00, and so on, until 23:59. The clock then resets to 00:00 (midnight), to begin counting the new day.
Digital time is written like a 24-hour timer, so 1.15am becomes 01:15, and 2.45pm becomes 14:45.
7am is written as 07:00. 12pm (midday) is written as 12:00. In the afternoon, the clock numbers continue to increase, so that 1pm becomes 13:00, and 2pm becomes 14:00, and so on, until 23:59. The clock then resets to 00:00 (midnight), to begin counting the new day.
Digital time is written like a 24-hour timer, so 1.15am becomes 01:15, and 2.45pm becomes 14:45.
Challenge: Can you convert these analogue times into digital times? Remember that a digital clock is like a timer and it just keeps adding an extra hour after 12pm.
- 6.30am
- 2.30pm
- 11.30am
- 6.30pm
Minutes in an hour
There are 60 minutes in an hour. In analogue time, we break up the hour into halves again. We usually say that the first 30 minutes are past the hour and next thirty minutes are to the hour.
For example:6.05pm would be called 'five past six' because 5 minutes have passed since the hour of 6pm. However, 6.55pm would be called 'five minutes to seven' because there are only 5 minutes to go until the next full hour of 7pm.
If you are working out how long things will take, such as on train timetable, you can calculate time by working out how many minutes there are to go until the next hour then add on the remaining minutes.
So, if a train leaves Melbourne at 09:55 and arrives in Springvale at 10:30, we can find out how long the journey takes by adding the amount of minutes it takes to get from 9:55 to 10:00 (5 minutes) and then add on the time it takes from 10:00 until 10:30 (30 minutes).
So 5 minutes added to 30 minutes = 35 minutes.
For example:6.05pm would be called 'five past six' because 5 minutes have passed since the hour of 6pm. However, 6.55pm would be called 'five minutes to seven' because there are only 5 minutes to go until the next full hour of 7pm.
If you are working out how long things will take, such as on train timetable, you can calculate time by working out how many minutes there are to go until the next hour then add on the remaining minutes.
So, if a train leaves Melbourne at 09:55 and arrives in Springvale at 10:30, we can find out how long the journey takes by adding the amount of minutes it takes to get from 9:55 to 10:00 (5 minutes) and then add on the time it takes from 10:00 until 10:30 (30 minutes).
So 5 minutes added to 30 minutes = 35 minutes.
Time problems
Follow these tips when solving time problems:
How long does it take for the 11.55 train from Normington to get to Kirkfield?
- If some of the times in the problem are in seconds, some in minutes and some in hours, change some of them so they are either all in seconds, all in minutes or all in hours.
- When reading timetables, make sure you know what type of information is in each column and row.
How long does it take for the 11.55 train from Normington to get to Kirkfield?
(The empty space in the table means the 10:39 train from Normington doesn't stop at Baskwell.)
Look along the Normington row until you reach the column that starts with the 11.55.
Look down that column until you get to Kirkfield and read off the time, 12.44.
Now you need to find the difference between 11.55 and 12.44. A good way to do this is to break up the time into smaller units within each hour.
Look along the Normington row until you reach the column that starts with the 11.55.
Look down that column until you get to Kirkfield and read off the time, 12.44.
Now you need to find the difference between 11.55 and 12.44. A good way to do this is to break up the time into smaller units within each hour.
5 + 44 = 49 minutes.
So the 11.55 train from Normington takes 49 minutes to get to Kirkfield.
Example 2
Sammy wakes up at 7.00am. He eats his breakfast at 7.30am and sets off for school at 8.30am. School starts at 9.00am.
First break is at 10.30am and by 12.00pm in the afternoon he is ready for lunch. School finishes at 3.30pm when Sammy is picked up by his Dad. He eats tea at 5.00pm and then leaves for football practice, which starts at 6.00pm.
When he gets home at 7.30pm, he has a bath and a snack, making his way up to bed at 8.30pm so he is bright and fresh for school in the morning.
So the 11.55 train from Normington takes 49 minutes to get to Kirkfield.
Example 2
Sammy wakes up at 7.00am. He eats his breakfast at 7.30am and sets off for school at 8.30am. School starts at 9.00am.
First break is at 10.30am and by 12.00pm in the afternoon he is ready for lunch. School finishes at 3.30pm when Sammy is picked up by his Dad. He eats tea at 5.00pm and then leaves for football practice, which starts at 6.00pm.
When he gets home at 7.30pm, he has a bath and a snack, making his way up to bed at 8.30pm so he is bright and fresh for school in the morning.