2021-22 SCIENCE CH 12 MOTION AND TIME
(TOPICS TAUGHT AND HOMEWORK)
DATE: 23/7/2021
GRADE: 7 C
CHAPTER: MOTION AND TIME
TOPICS TAUGHT:
- DIAGNOSTIC TEST(GOOGLE FORM)GOOGLE CLASSROOM
- INTRODUCTION
- TIME
HOMEWORK: REVISE THE TOPICS TAUGHT
DATE: 27/7/2021
GRADE: 7 C
CHAPTER: MOTION AND TIME
TOPICS TAUGHT:
- define time
- the importance of measurement
- the SI units of measuring mass, time, length and temperature
Measuring Time
There are many events in nature that repeat after a time interval:
Morning – The rising of the sun
Day and Night – The time between the sunrise and sunset
Month – The time between two new moons
Year – The time the earth takes to complete its one revolution around the sun
Time measuring devices or clocks - Clocks use the concept of periodic motion to measure time. It means that it uses motion that repeats itself in equal amounts of time. There are different types of time measuring devices.
Sundial – It uses the position of the sun to depict time
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Sand Clock (hourglass) – It uses sand to measure time 
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Water Clock – It uses water to measure time
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Pendulum Clock – It uses a pendulum to measure time  |  |
Quartz Clocks – They have an electric circuit that works with the help of cells. They provide accurate time. |  |
Homework- Measurement activity.
DATE: 28/7/2021
GRADE: 7C
CHAPTER: MOTION AND TIME
TOPICS TAUGHT:
Measuring Time
There are many events in nature that repeat after a time interval:
Morning – The rising of the sun
Day and Night – The time between the sunrise and sunset
Month – The time between two new moons
Year – The time the earth takes to complete its one revolution around the sun
DATE: 29/7/2021
GRADE: 7 C
CHAPTER: MOTION AND TIME
TOPICS TAUGHT:
Hourglass
An hourglass (or sand-glass, sand timer, or a clock) is a device used to
measure the duration of time. The Romans used sand clocks which worked
on the principle that a definite quantity of sand takes a constant time
to fall from the upper chamber to the lower chamber. It cannot be used
to find the exact time, but can be used to measure the predetermined
time interval.
Water clock
A water clock is also known as Clepsydra. To
measure the time, it uses the fact that equal
amounts of water take the same interval of
time to flow through an opening
Discuss about the different ancient devices used for measuring time.
Video (Sundial) and Video (Water Clock) for better understanding of the functioning of sundial and water clock.
MAKE A MODEL OF WATER CLOCK/SUNDIAL/SHADOW CLOCK (WILL BE DISPLAYED IN CLASS .
HOMEWORK: REVISE THE TOPICS TAUGHT. WATCH THE VIDEOS GIVEN ON BETWEEN US-STUDENT RESOURCE
DATE: 3/8/2021
GRADE: 7 C
CHAPTER: MOTION AND TIME
FOR PRACTICE-
Convert the following and write the answers in the notebook.
CAN BE DONE ALONG WITH NOTEBOOK EXERCISE.
1. 40 minutes to seconds
2. 8 hours to minutes 3.
150 minutes to seconds
4. 7.5 hours to minutes
5. 300 minutes to hours
6. 4 hours to seconds
7. 1 day to minutes
8. 365 days to hours
9. 10 days to minutes
10. 340 minutes to hours
TOPICS TAUGHT: SUNDIAL CLOCK, WATER CLOCK, HOUR CLOCK, SAND CLOCK CANDLE CLOCK, PENDULUM, Measurement of time using a simple pendulum
Homework- REVISE THE TOPICS TAUGHT
DATE: 10/8/2021
GRADE: 7 C
CHAPTER: MOTION AND TIME
TOPICS TAUGHT:
Uniform and Non-Uniform Motion TOPICS TAUGHT: MOTION, SLOW AND FAST MOTION, CONCEPT OF SPEED, UNIT OF SPEED, UNIFORM AND NONUNIFORM MOTION
Homework- REVISE THE TOPICS TAUGHT
ASYNCHRONOUS ACTIVITY
Watch Video (Uniform and non uniform motion) and write the answers to the questions asked in the video.
Plot a graph for the readings given on page no. 205 of the textbook. Check your graph with the ones given on page no. 206 of the textbook. Upload the photograph/scanned copy of their work
DATE: 11/8/2021
GRADE: 7 C
CHAPTER: MOTION AND TIME
TOPICS TAUGHT:
Distance-time Graph
A graph which represents the distance travelled by an object with respect to time is called a distance-time graph.
| Making a distance-time graph: |
1. Mark the x-axis and y-axis and divide them in equal quantities. |  Figure 11: Take the first quadrant |
2. Choose one scale to represent distance (for example, x-axis to represent distance where 1 km = 1 cm) and the other to represent time (for example, y-axis to represent the time where 1 min = 1 cm). |  Figure 12: Choosing the scale |
3. Mark the values of time and distance in the graph.
4. Mark the set of values of time taken and distance covered in that time by the object in the graph. For example, if 1 km is covered in 1 minute then mark 1 unit on both the x-axis and y-axis. | 
Figure 13: Marking the values for time and distance |
5. Now draw lines parallel to x-axis and y-axis at the points that you have marked.
6. Mark the points where these lines intersect on the graph. These points show the position of the moving object.
7. Now join all the points of intersection and obtain a straight-line graph.
8. This is the distance-time graph of a moving object. The shape of the distance-time graph can be the following: | Shape of Graph | Interpretation | Straight line | The object has a uniform or constant speed | Parallel to time-axis | It is a stationary object | Curve shape | The object has a non-uniform speed |
|
 Figure 14: Obtaining a straight line graph |
To find the speed of the distance-time graph
Speed = distance/time = (final position of object – initial position of object)/time taken by object
Also, the speed of the distance-time graph can be calculated by the Slope of a graph. The steeper the slope of the graph, the more is the speed of the object. For example, in the graph given below object A has a steeper slope. This means that object A is moving at a higher speed than object B.
Homework- Complete Notebook work and Upload Worksheet on between us.
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