# Time Measure primary 6 second term Week 9

Class:- Basic 6

Primary 6

Second Term

Mathematics

Subject:- Mathematics

Week:- 9

Topic: Time

Behavioral objective:- At the end of the lesson the pupils should be able to:-

1. Tell the time on a 24-hour clock

2. Read time tables on journeys

3. Calculate average speed

4. Calculate athletic time.

Instructional material/Reference material:-Online Materials , Textbooks , Workbook

Building Background /connection to prior knowledge : Students are familiar with wall clock and wrist watches which are object that tells time

Content

Time simply refers to the duration it takes to perform a task. Time refers to how long we have been doing something or how long it takes to perform a specific task. The basic unit of measuring time is seconds. Other units of time measurements are minutes, hours, days, weeks , months, years etc.

Wall clock, Digital watches , stop watches , weather observations , calendars are all used to measure time intervals .

24 hours clock

Bus, railway, ship and airline timetables use the 24-hour clock to state the times of departure and arrival of journeys.

Remember: The 24-hour clock numbers hours from 00 to 24,

that is, for a whole day from midnight to midnight.

When 24-hour clock times are written with four figures,

the first two figures represent hours and the last two figures represent minutes past the hour.

A point usually separates the hours from the minutes, e.g.

1. 7.25 am is written as 07.25

2. 7.25 pm is written as 19.25

You have to add on 12 hours if it is pm or after. That is why 7.25 pm is 19.25. When it gets to midnight, the 24-hour clock changes from 13.59 to 00.00

Reading timetables of journeys (Flights and trains)

Train time-table

Passenger train schedule

The following passenger train services are currently running across the country.

O Lagos – Ilorin (Tuesdays, Fridays & Saturdays)

– Departs Iddo 09.00 hrs

– Arrives Ilorin 18:34 hrs of same day.

O Ilorin – Lagos (Wednesdays, Saturdays & Sundays)

– Departs Ilorin 11.00 hrs of Wednesday

– Arrives Lagos 20.59 hrs of same day

– Departs Ilorin 09.00 hrs on Saturdays and Sundays

– Arrives Lagos 20.59 hrs.

O Lagos – Kano (Every Friday)

– Departs Iddo 12.00 hrs

– Arrives Kano 17.01 hrs on Saturday

O Kano – Lagos (Every Monday)

– Departs Kano 09-00 hrs

– Arrives Lagos 14.24 hrs on Tuesday

O Offa – Kano (Every Tuesday)

– Departs Offa 22.00 hrs

– Arrives Kano 18.05 hrs on Wednesday

O Kano – Offa (Every Friday)

– Departs Kano 08.30 hrs

– Arrives 05.35 hrs on Saturday

O Minna – Kaduna – Minna (Every Sunday, Monday & Tuesday)

O Nguru – Kano (Every Tuesday and Friday)

O Kaduna Inter-city [Commuter service] (Mondays – Saturdays)

O Lagos Inter-city [Commuter service] (Mondays – Saturdays)

Average speed

Speed is often measured in kilometres per hour. This is written for short as km/h. To find the average speed, you divide distance by time taken. That is:

Average speed = Distance covered/ Time Taken

Examples

Study how the following word problems have been solved.

1. An aeroplane flies 2800km in 5 hours. What is its average speed?

Average speed = Distance covered/Time Taken

2800/ 5 = 560km/h

When you are asked to find the time covered, you use the formula

Distance covered/ Average Speed∴ In the previous example you did 2800/ 560 = 10/ 2 = 5 hrs

To find the distance covered, you do average speed multiplied by time.

That is 560 × 5 = 2800km

2. Abel walked a distance of 90metres in 1minute. Find his walking speed in km/h.

Speed = Distance/Time = 9÷1 000km ÷ 1\ 60 h = 90/ 1 000 × 60km/h = 5410 km/h = 5.4km/h

Athletic time

Short periods of time are recorded in seconds (s) or fractions of a

second. Athletic time is recorded in seconds but using 1minute plus for

long distant races.

For this purpose a stop watch us

used to give accurate timing.

The minute shown on this stopwatch is between 0 and 1. The second is 14.2. An electric timer is needed if a measurement to two decimal places is required (1/100s).We measure short periods of time in seconds. There are 60seconds in

1 minute. A stopwatch or seconds pendulum can be used to record short periods of time, such as in races, debates, quiz competitions and mental sums.

Group activity

Use the stopwatch to time these events.

1. How long does it take your partner to blink her eyes?

2. How long does it take your partner to walk from one end of theclassroom to the other?

3. How long does it take to write a sentence? (Choose the same sentence.)

4. How long does it take to boil water in an electric kettle?

5. How long does it take to boil a cup of water on a stove?

6. How long does it take to warm a plate of rice in a microwave oven?

7. How long does it take to defrost a frozen chicken?

Evaluation:-

1. A motorist left his home at 10.00 am to travel to a city of distance 260km. He reckoned he could average 80km/h. At what time would he arrive at the city?

2. Express a speed of 60metres per second in kilometres per hour correct to 1 decimal place.

3. A motor car travels at 60km/h. At this speed how far will it travel in:

a) 1min b) 10min c) 3/4h?

4. The distance between Ibadan to Ilesha is 120 kilometres. A passenger lorry left Ilesha for Ibadan at 6 a.m and arrived back in Ilesha at 12 noon. It stopped at Ile-Ife for 30minutes, at Gbongan for 1 hour and at Ibadan for 11/2 hours. Find the time spent traveling, not including stopping time. With this time find the average speed for the journey. (Remember to exclude stopping time.)

5. How many minutes are there between each start and finish time.

Start. Finish Start Finish

a) 20.20 → 23.40 b) 23.25 → 01.10

6. A flight that was scheduled to take off at 22.55 was delayed for 25 minutes. What time did it finally take off?

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