# Time Measure primary 6 second term Week 9

**Class:- Basic 6**

** Primary 6**

**Second TermÂ **

**MathematicsÂ **

**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 , WorkbookÂ **

**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.**

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

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**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 â€“ Ilorin (Tuesdays, Fridays & Saturdays)**

**â€“ Departs Iddo 09.00 hrs**

**â€“ Arrives Ilorin 18:34 hrs of same day.**

**O Ilorin â€“ Lagos (Wednesdays, Saturdays & Sundays)**

**â€“ Departs Ilorin 11.00 hrs of Wednesday**

**â€“ Arrives Lagos 20.59 hrs of same day**

**â€“ Departs Ilorin 09.00 hrs on Saturdays and Sundays**

**â€“ Arrives Lagos 20.59 hrs.**

**O Lagos â€“ Kano (Every Friday)**

**â€“ Departs Iddo 12.00 hrs**

**â€“ Arrives Kano 17.01 hrs on Saturday**

**O Kano â€“ Lagos (Every Monday)**

**â€“ Departs Kano 09-00 hrs**

**â€“ Arrives Lagos 14.24 hrs on Tuesday**

**O Offa â€“ Kano (Every Tuesday)**

**â€“ Departs Offa 22.00 hrs**

**â€“ Arrives Kano 18.05 hrs on Wednesday**

**O Kano â€“ Offa (Every Friday)**

**â€“ Departs Kano 08.30 hrs**

**â€“ Arrives 05.35 hrs on Saturday**

**O Minna â€“ Kaduna â€“ Minna (Every Sunday, Monday & Tuesday)**

**O Nguru â€“ Kano (Every Tuesday and Friday)**

**O Kaduna Inter-city [Commuter service] (Mondays â€“ Saturdays)**

**O Lagos Inter-city [Commuter service] (Mondays â€“ 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 Speedâˆ´ 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 Ã— 5 = 2800km**

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

**Speed = Distance/Time = 9Ã·1 000km Ã· 1\ 60 h = 90/ 1 000 Ã— 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 â†’ 23.40 b) 23.25 â†’ 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?**