Mathematics K–6 · Years 5–6

24-hour time and real timetables

Measurement and space

Practical, model not builtLow risk

This site has no interactive model of its own. Where a step or a material names a Concept Studio model, simulation or tool, it has not been built; an external simulation a step names (for example PhET) is not part of this site.

The idea

The 24-hour clock numbers the hours from 00 to 23 so that a time needs no am or pm, and the length of a trip on a timetable is the difference between two times, counted on to the next hour and then to the arrival time.

What you need

a geared analog clock with a paper ring fixed outside the numerals, labelled 13 beside the 1 through to 23 beside the 11, and 00 beside the 12
a printed timetable for a local bus, train or ferry route from transportnsw.info
a digital clock or device set to 24-hour time
a recording sheet

How to do it

Turn the clock hands through a whole day from midnight, saying each hour in 12-hour and in 24-hour time.
Convert ten times each way (for example 2:35 pm, 12:15 am, 18:40, 00:05) and write down the rule used.
On the timetable, choose a service and read its departure and arrival times. Find the trip length by counting on to the next hour, then whole hours, then the minutes to the arrival time.
Plan a trip that arrives at a destination by a given time, allowing 10 minutes to walk from the stop, and choose the latest service that works.
Check each trip length on the geared clock by turning the minute hand from the departure time.

What you should see

2:35 pm is 14:35, 12:15 am is 00:15, 18:40 is 6:40 pm and 00:05 is 12:05 am; the rule adds 12 to the hours from 1 pm to 11 pm and writes the hour after midnight as 00. A service departing at 08:47 and arriving at 13:12 takes 13 minutes to 09:00, 4 hours to 13:00 and 12 minutes more, which is 4 hours 25 minutes. A trip from 22:50 to 06:15 the next morning takes 7 hours 25 minutes. Trip lengths worked out from the real timetable agree with the check on the geared clock.

What changes

This activity lists no variables to change, measure and keep the same.

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

14:35 is 4:35 pm because the hour ends in 4.
A trip length is found by subtracting the times as ordinary numbers, so 13:12 - 08:47 gives 4:65.

Safety card

Low riskLearners carry it out

Hazards

none beyond an ordinary classroom

Controls

none needed

Note

No chemicals or heat are used, so the NSW Department of Education Chemical Safety in Schools package is not needed; ordinary classroom supervision under the school's usual risk management.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Mathematics K-10 Syllabus (2022), NSW Education Standards AuthorityMA3-NSM-02 MAO-WM-01
Australian Curriculum v9AC9M5M03AC9M6M03

Sources

The pages the author read to write this activity.

All Concept Studio activities