PPT: Measurement of Time and Motion | PPTs for Class 7 PDF Download

 Page 1


Measurement of Time 
and Motion
Page 2


Measurement of Time 
and Motion
I n t r o d u c t i o n
Time and motion are essential concepts that 
help us organize our lives and understand the 
world around us. This chapter explores how 
humans have measured time, from ancient 
methods using natural cycles to modern, 
precise devices like atomic clocks.
It also introduces the idea of speed, which 
helps us compare how fast or slow objects 
move, and explains the difference between 
uniform and non-uniform linear motion. 
Through examples like sprint races and train 
journeys, students will learn how time and 
motion are measured and applied in everyday 
life and science.
Page 3


Measurement of Time 
and Motion
I n t r o d u c t i o n
Time and motion are essential concepts that 
help us organize our lives and understand the 
world around us. This chapter explores how 
humans have measured time, from ancient 
methods using natural cycles to modern, 
precise devices like atomic clocks.
It also introduces the idea of speed, which 
helps us compare how fast or slow objects 
move, and explains the difference between 
uniform and non-uniform linear motion. 
Through examples like sprint races and train 
journeys, students will learn how time and 
motion are measured and applied in everyday 
life and science.
Measurement of Time
Historical Need
Humans have always needed to keep track of time for activities 
like farming, planning events, and navigation. By observing 
repeating patterns in nature, such as the Sun rising and setting, 
they developed ways to measure time. Over time, they invented 
devices to measure smaller intervals within a day, leading to the 
highly accurate clocks we use today.
Natural Cycles
Long ago, people noticed that certain natural events, like the 
Sun's daily rising and setting, the Moon's phases, and the 
changing seasons, happened at regular intervals. They used 
these cycles to create calendars, defining a day as the time 
between one sunrise and the next.
Page 4


Measurement of Time 
and Motion
I n t r o d u c t i o n
Time and motion are essential concepts that 
help us organize our lives and understand the 
world around us. This chapter explores how 
humans have measured time, from ancient 
methods using natural cycles to modern, 
precise devices like atomic clocks.
It also introduces the idea of speed, which 
helps us compare how fast or slow objects 
move, and explains the difference between 
uniform and non-uniform linear motion. 
Through examples like sprint races and train 
journeys, students will learn how time and 
motion are measured and applied in everyday 
life and science.
Measurement of Time
Historical Need
Humans have always needed to keep track of time for activities 
like farming, planning events, and navigation. By observing 
repeating patterns in nature, such as the Sun rising and setting, 
they developed ways to measure time. Over time, they invented 
devices to measure smaller intervals within a day, leading to the 
highly accurate clocks we use today.
Natural Cycles
Long ago, people noticed that certain natural events, like the 
Sun's daily rising and setting, the Moon's phases, and the 
changing seasons, happened at regular intervals. They used 
these cycles to create calendars, defining a day as the time 
between one sunrise and the next.
Early Time Measurement Devices
Sundials
These used the shadow cast by the Sun's light on an object to 
show the time of day. As the Sun moved, the shadow's position 
changed.
Water Clocks
These measured time using water flow. One type had water 
flowing out of a marked vessel, while another used a bowl with a 
hole that sank when filled with water.
Hourglasses
These used sand flowing from one bulb to another to measure 
time.
Candle Clocks
These were candles with markings that showed time as they 
burned down.
Page 5


Measurement of Time 
and Motion
I n t r o d u c t i o n
Time and motion are essential concepts that 
help us organize our lives and understand the 
world around us. This chapter explores how 
humans have measured time, from ancient 
methods using natural cycles to modern, 
precise devices like atomic clocks.
It also introduces the idea of speed, which 
helps us compare how fast or slow objects 
move, and explains the difference between 
uniform and non-uniform linear motion. 
Through examples like sprint races and train 
journeys, students will learn how time and 
motion are measured and applied in everyday 
life and science.
Measurement of Time
Historical Need
Humans have always needed to keep track of time for activities 
like farming, planning events, and navigation. By observing 
repeating patterns in nature, such as the Sun rising and setting, 
they developed ways to measure time. Over time, they invented 
devices to measure smaller intervals within a day, leading to the 
highly accurate clocks we use today.
Natural Cycles
Long ago, people noticed that certain natural events, like the 
Sun's daily rising and setting, the Moon's phases, and the 
changing seasons, happened at regular intervals. They used 
these cycles to create calendars, defining a day as the time 
between one sunrise and the next.
Early Time Measurement Devices
Sundials
These used the shadow cast by the Sun's light on an object to 
show the time of day. As the Sun moved, the shadow's position 
changed.
Water Clocks
These measured time using water flow. One type had water 
flowing out of a marked vessel, while another used a bowl with a 
hole that sank when filled with water.
Hourglasses
These used sand flowing from one bulb to another to measure 
time.
Candle Clocks
These were candles with markings that showed time as they 
burned down.
Do you Know?
The world's largest stone sundial, the Samrat Yantra, was built around 300 years ago at the Jantar 
Mantar, in Jaipur, Rajasthan, a UNESCO World Heritage site that houses several astronomical 
instruments. With its imposing height of 27 metres, its shadow moves at about 1 millimetre per second 
and falls on a scale fi nely marked to measure time intervals as short as 2 seconds. Like any sundial, it 
measures local or 'solar time', requiring a correction to determine Indian Standard Time.