Page 105 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

Compare your measurements with those of others.

Are all measurements the same?
Why are the measurements not equal?

Don't you feel that all should have got the same measurement?
What can we do about it?
Try to measure the length of the same table using the ribs of a
coconut tree leaf, of the same length.

Now, isn't the measurement that everyone got the same? Didn't
you understand that while measuring the length of an object, the
results of all will be the same only if all use objects of same length
or same scale to measure?
In olden days different scales were used for measuring length.
Write down the scales familiar to you.

vaara

one forearm (muzham)

Now, try to write down the difficulties that arise due to the use of
different scales in different parts of the world.

Accuracy cannot be ensured.

Let’s see how this problem has been solved.
A standard scale of a definite length has been recognised world
wide for measuring length. This standard scale is the unit of length.

The basic unit of length is metre. Its symbol is m.

Can you measure the length of a pencil accurately using a one
metre long rod?

Smaller units of length

Examine a metre scale.
You might have observed long lines as well as numbers
marked along its sides.

Markings on the scale start from one. Which marking falls
last on the scale?
Fig 8.2
104 Basic Science VIII