Page 108 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

On the basis of the given information, answer the Precautions to be taken
following questions: while measuring length

The use of plastic carry bags having thickness While measuring the length of an
below the stipulated level has been object, keep the scale close to the
prohibited. In which unit is the thickness of object without any inclination, as
such bags expressed? shown in Figure 8.9(b)

The distance from the earth to a planet in the
solar system is 4 AU. What do you mean by
this?
Find out how many kilometre is one light
year and write it down in your science diary.

Which is the convenient unit to express the Fig 8.9 (a)
distance from the earth to the star thiruvathira?

In order to measure the length of an object
accurately, we should be careful about certain
points. Try to understand these points analysing
Fig 8.9 (a) (b) (c).
What will you do if the edges of a scale are broken Fig 8.9 (b)
or if the markings are not clear? Note it down in
The position of the eye is very important
your science diary.
while taking the measurement. Observe
Instead of measuring from the first marking the figure 8.9(c) and understand where
on the scale start from another whole number. the position of the eye should be.
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Fig 8.10
What is the length of the pencil shown in
Fig 8.9 (c)
Fig 8.9 (c)? Note it down.

Now you might have understood the basic unit for measuring
length and its smaller as well as bigger units. You might have
also observed the situations in which length is to be measured.
Have you ever bought sugar from a shop? In which unit do
you get it? What does this measurement indicate?

Fig 8.11
Basic Science VIII 107