NCERT Class 5 Mathematics Maths Mela Chapter 12 Racing Seconds PDF Download

Chapter 12: Racing Seconds

Raghav practices yoga in the morning.

[Figure 12.1: Two analog clocks showing Raghav in yoga poses at different times, See in your textbook]

Let us find out

1. At what time did Raghav start practising Yoga? ....................
2. At what time did he finish? ................
3. How much time did he spend practising Yoga? ....................
4. Find the time elapsed between the given time periods. Share your strategies.
   1. 01:15 p.m. to 01:42 p.m.?
   2. 03:18 p.m. to 08:18 p.m.?
   3. 09:15 a.m. to 11:30 a.m.?
5. The table below shows the time taken by 3 children to paint a picture.

   Name	Time Taken
   Raghav	1 hour 20 minutes
   Rani	2 hours 10 minutes
   Ritu	1 hour 35 minutes

   1. Who took the longest time?
   2. Who took the least time?

6. Fill in the blanks by writing the time in the appropriate format.

   Time in 12-hour fromat	Time in 24-hour fromat
   05:30 a.m.	05:30 hours
   .............	08:35 hours
   11:55 a.m.	......... hours
   02:30 p.m.	14:30 hours
   05:30 p.m.	......... hours
   09:35 p.m.	......... hours

7. Match the following.

   Time in 12-hour format	Time in 24-hour format
   06:30 a.m.	01:30 hours
   08:45 p.m.	23:45 hours
   11:45 p.m.	06:30 hours
   04:30 a.m.	20:45 hours
   07:30 p.m.	04:30 hours
   01:30 a.m.	19:30 hours

School Race

Akira, Sunita, and Mary are participating in a 200 m-walking race.

[Figure 12.2: Three children walking in a race and a podium showing their finish times at 01:55, 01:56, and 01:57, See in your textbook]

Do you notice the use of a new unit 'seconds' in the picture?

1 min = 60 seconds

In situations like a race, seconds help us observe small differences in time taken by participants. Each participant took 1 minute but how much more?

Identify the child who won the race. How much time did the child take?

Teacher's Note

When you read time from a clock, look at where the minute hand (longer hand) and the second hand (thinner hand) are pointing. The second hand makes a complete circle every 60 seconds, which is one minute. In a race, seconds matter because they show which runner finished first when all runners took about the same time in minutes.

Let Us Do

Estimate whether you would take seconds or minutes to complete the following activities. Tick the appropriate cell.

List events other than the ones listed above that you can do or that can happen in less than a minute or in a few seconds.

........................................................................................... ........................................................................................... ........................................................................................... ........................................................................................... ........................................................................................... ........................................................................................... ........................................................................................... ........................................................................................... ........................................................................................... ........................................................................................... ........................................................................................... .............................................................................................

Estimate and verify how many of these you can do in a minute.

Note for the Teachers

Let the learners observe and discuss who stood first, who stood second, and who stood third and why. Help them understand the difference between minutes and seconds and seconds as a unit which adds precision in measuring short time duration. Get the learners to observe that 60 movements of the seconds hand leads to a shift in the minute hand.

Let Us Find

1. Find out the number of times you can skip the rope in 10 seconds.
2. How long does it take you to write the word FRIEND?
3. How long does it take you to run 100m?

Let Us Do

Observe the clocks and fill in the blanks.

1

[Figure 12.3: Two analog clocks showing Rani getting out of bed, See in your textbook]

Rani took __________ sec. to get out of her bed.

2

[Figure 12.4: Two analog clocks showing Raghav moving from his room to the kitchen, See in your textbook]

Raghav took ________ sec. to move from his room to the kitchen.

3

[Figure 12.5: Two analog clocks showing Ritu picking up a piece of paper from the floor, See in your textbook]

Ritu took ________ sec. to pick up a piece of paper from the floor.

4

[Figure 12.6: Two analog clocks showing Raghu washing his spoon and plate, See in your textbook]

Raghu took ________ sec. to wash his spoon and plate.

Teacher's Note

To find how many seconds passed between two clock readings, look at where the second hand (thin hand) points on each clock. Count the number of second marks it moved, or subtract the smaller time from the larger time. For example, if the second hand moves from 2 to 5, that is 3 seconds (from 10 seconds to 15 seconds).

Key Points

• One minute equals 60 seconds. Seconds are used to measure very short time periods, especially when the difference between activities or events is small.
• When reading a clock to find elapsed time in seconds, observe where the thin second hand points at the start and at the end, then count how many second marks it moved.
• Different activities take different amounts of time: some take only seconds (like blinking or snapping fingers), while others take minutes (like drinking a glass of water or making a phone call).
• Time can be shown in 12-hour format (with a.m. or p.m.) or 24-hour format (using hours from 00 to 23). The same time can be written both ways, like 02:30 p.m. equals 14:30 hours.

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