Page 1 - Lesson notes- Measuring length of curved line

SAI INTERNATIONAL SCHOOL

Class-6
Lesson Notes
Subject-Physics

Ch- Measurement and Motion
Subtopic- Measuring length of a curved line and Estimation

Measuring length of a curved line: -
The length of a curved line can be measured in two ways-
a) Using a thread- Here we use a string or a thread over the curved line using our
finger and then measure the length of the thread with a ruler.
b) Using a divider
• Take a divider and separate its two tips by a small distance, say by 1 cm with
the help of ruler. Measure the curved line with that distance of the divider.
• Place one tip of the divider at the beginning of the curved line. Place another
tip of the divider on the curved line and put a mark at this point.
• Continue moving the pair of dividers forward till the entire curved line divide
into segments of equal length.
• Count the number of segments.
• If some part of the curved line is left over then measure it separately.

The length of curved line = (number of segments of equal length x distance
between the tips of the divider) + length of the left-over part.

Estimation in Measurement:
The ability to guess the amount of something without actual measurement is called
estimation.
Estimation gives an approximate value of the quantity.
E.g. While cooking one uses an estimate instead of exact measurement.
While buying wall paper, estimation helps rather than accurate measurement.

Advantages of estimation:
Estimation helps us to solve problems quickly without the need of actual
measurement.
It saves time. For e.g. When planning a trip, we generally gather estimate of
distance, time and cost.