Page 165 - Science Class 07

18
18
18

Time Measurement and Motion

• Ancient Time Measurement System • Time Measurement in Modern Time
• Modern Time Measurement Devices • Rest and Mo on • Slow and Fast Mo on
• Uniform and Non-uniform Mo on
• Devices Used to Measure Distance and Speed of Moving Objects

When you get up early in the morning, you Jai Singh, had built many sundials in different
look at the clock to know how much me you ci es of India during 18th century. He was a

are le with to prepare yourself for the school. great scholar of mathema cs and astronomy.
The school bell rings at a certain me and the Jantar Mantar situated in Delhi is one of the
daily ac vity of the school begins. You come famous sundials built by him.
from school on a certain me and even you go
to bed on certain me. It means we do most of
our work according to prescribed me. Trains,
aeroplanes, buses, etc. arrive and depart on
certain me. In our modern and technological
world, me has become very important for the
smooth running of the society.

ANCIENT TIME MEASUREMENT SYSTEM
In ancient me, people did not have watches to Sundial

know the me. They got a rough idea about
me from some natural events like sunrise,
sunset, etc.
With the passage of me, people developed
sundials to know me more accurately. The

sundials were based on the change in the
length of the shadow with change in posi on
of the sun. The famous King of Jaipur, Maharaja Jantar Mantar

Science-7 165