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# Time Units of Work

Time is a measure but it is a different from the other measures in that it cannot be seen or touched. However, we are surrounded by the effect of time passing, for example, day to night and one season to another. There are two aspects of time students must develop:

• time as an instant which can be named, for example, 6:15;
• time as a duration which describes an amount of time that has passed, for example, a minute, the afternoon, the year.

### Level 1 Time

 Achievement Objectives Learning Outcomes Unit title GM1-1 sequence events within a daydescribe a duration as long or shortname and order the days of the week Passing time directly compares the duration of two eventsuses non-standard units to compare the duration of two or more eventstell time to the hour and half hour using analogue clocks How long now

### Level 2 Time

 Achievement Objectives Learning Outcomes Unit title GM2-1 recognise the length of a minuterecognise the length of a secondtell time after the hour by counting minutes Just a minute tell time to the hour and half hour using analogue clockstell time to the hour and half hour using digital clockssolve time problems involving hours and half hours Clock wise GM2-1NA2-1 estimate the time taken for daily activities in hours and minutesuse advanced counting or partitioning strategies to solve problems involving minutes and hourscheck the reasonableness of answers obtained using a calculator How Long Does it Take?

### Level 3 Time

 Achievement Objectives Learning Outcomes Unit title GM3-1 measure time in periods of up to 15 minutes compare non standard and standard measurements for time Calibrating Clocks

### Level 4 Time

 Achievement Objectives Learning Outcomes Unit title GM4-1GM4-4 read and use a variety of timetables and chartsperform calculations with time, including 24-hour clock times and time zones Time Zones GM4-1GM4-2NA4-1 calculate speed from measured distance and timesolve multiplication problems using doubling and halving strategiesuse known multiplication facts to solve multiplication problems How fast is fast?

### Time

Students’ experiences with time throughout the learning sequence has two aspects:
- duration and telling time.

Telling time must enable them to:

1. develop an understanding of the size of the units of time. This includes being able to estimate and measure using units of time;
2. read and tell the time using both analogue and digital displays.

### Stage One: Identifying the attribute

Duration
It is important that students develop an understanding of the duration of time in addition to being able to identify moments of time. Unlike the other time measures, students are frequently introduced to standard units of time, for example, days of the week, and hour times, before they have grasped the concept of the duration of time.

It is important that the concept of time as duration is emphasised from the start. Students need to have lots of experiences to establish that the duration of an event requires noting the starting and finishing points of time. Arranging pictures of events in the correct sequence helps develop the concept of duration. The use of words such as before, after, soon, now, later, bedtime and lunchtime, helps develop understanding of the attribute of time.

Looking at standard cycles of time follows from the sequencing of daily events. Students learn the sequence of the days of the week, but initially may not fully understand the way we use the names repeatedly. The terms today, tomorrow, yesterday and weekend, can be learnt in relation to the cycle of days. The sequence of months can also be developed as well as the grouping of the months into seasons.

### Stage Two: Comparing and ordering

Duration
Comparing the duration of two events is the second stage in developing an understanding of time passing. This can be done by directly comparing two activities that have common starting points, for example, a song on a tape or running around the building.

You can indirectly compare the duration of events by using a sand timer or a candle timer.

Telling time
At this stage time telling time skills will focus on hour and half-hour.

### Stage 3: Non-Standard units

Duration
Measuring the duration of events using non-standard or informal units is the third stage in the learning sequence. Beginning with non-standard but familiar units allows the students to focus on the process of repeatedly using a unit as a measuring device. Parts of the body provide interesting units for introductory use. Students can compare and order events using heartbeats, hand clapping and hopping.

Students can also make their own timing devises and calibrate these arbitrarily, for example, by making marks at regular intervals on a burning candle, or by letting sand run through a small hole into a calibrated container.

From the earliest of these experiences, students should be encouraged to estimate. Initially these estimations may be no more than guesses, but estimating involves the students in developing a sense of the size of the time unit. As everyday life involves estimating at least as frequently as finding exact measures, the skill of estimating is important.

Although non-standard units reinforce most of the basic measuring principles, students need to realise that they are limited as a means of communication. This can be highlighted through activities that involve the students measuring the duration of a single event using, for example, counting rhythms (one rhinoceros, two rhinoceros, three rhinoceros etc).

Telling time
The students’ skill in telling time can be extended to match their numeracy understanding. For example, the students may count in fives to tell time in five-minute intervals.

### Stage 4: Standard units

When students can measure the duration of events using non-standard units, they are ready to move to the use of standard units. The motivation for moving to this stage often follows from experiences where the students have used different non-standard units for the same event. They can then appreciate that consistency in the units used would allow for the easier and more accurate communication of duration.

Measuring with standard units involves the introduction of minutes, hours and seconds in addition to reading time on analogue and digital clocks.

Duration
The minute is often introduced first because it is small enough to measure common events. The duration of minute can be established by watching the second hand on a clock or by constructing a minute sand-timer. An appreciation for the size of a minute can be built up through lots of experience in measuring everyday events. For example, how many minutes does the song play for? How long is morning break? How long does it take to walk around the school building? How many times can you hop in a minute? How many linked cubes can you join a minute?

As the students become familiar with the size of a minute they should be given opportunities to estimate before measuring. Minutes need to be linked to the movement of the minute hand on the analogue clock and the digits on digital displays.

An understanding of the size of a second can be developed by investigating the relationship between seconds and minutes. This can be done by watching the digital displays on some watches, on stopwatches and on video-recorders. The students should be encouraged to develop their own reference for a second, for example, a counting pattern "one – banana – two – banana – three etc".

It is more difficult to give students a concept for one hour but references can be established for events that last an hour by setting an alarm to ring after an hour has passed.

The underlying number skills should be mastered before teaching students the skill of telling and reading time.

Students are likely to be able to read the time to the hour and half-hour prior to fully developing a conceptual understanding of the size of time units. The usual progression for teaching the skill of telling and reading time is:

• read time on the hour by identifying where the hands point for time on the hour;
• read time to the ½ and ¼ hour;
• read clock time after the hour by counting the minutes after the hour (in fives);
• use digital notation to record the number of minutes after the hour;
• read clock time before the hour by counting the minutes to the hour (in fives);
• refine time-telling skills by associating numerals 1, 2, 3, 4, and 5 with time 5, 10, 15, 20 and 25 after the hour;
• associate numerals 7, 8, 9, 10 and 11 with time before the hour;
• 24 hour notation.

### Stage 5: Applying and Interpreting

Once the students have an appreciation of the size of seconds, minutes and hours and the relationship between them, they can be introduced to time zones and time-lines. An understanding of time zones can be developed from contexts such as travel and holidays.

Phone or e-mail interactions with people in other time zones can be used to highlight the differences in time throughout the world.

Historical projects bring to life year time-lines.