Page 115 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

the above observation, answer the following questions and write
it down in your science diary.

If petrol, diesel etc., catches fire one should never try to
extinguish it using water. Why?

The rules to be followed while writing units

Haven’t you understood fundamental measurements and their
units? We have to observe certain rules according to international
standards while using these units and their symbols. They are
given below:
(1) The symbols of units are normally written using small letters
in the English alphabet. eg. m (metre), s (second), kg
(kilogram)

(2) But there are certain occasions on which capital letters of the
English alphabet are used as symbols. The units named after
persons are written like this.

Physical
Name of person unit symbol
quantity

Alessandro Volta Potential volt V
difference
Blaise Pascal Pressure pascal Pa

Sir Isaac Newton Force newton N

Table 8.6

(3) While writing the names of units never use capital letters.
eg. kelvin (correct) Kelvin (wrong)
newton (correct) Newton (wrong)

(4) Never use the plural form for symbols.
eg . 10 kg (correct) 10 kgs (wrong)
75 cm (correct) 75 cms (wrong)

(5) Never use full stop or comma after a symbol except at the
end of a sentence.
eg. 75 cm is the length of a table. (correct)

75 cm. is the length of a table. (wrong)

114 Basic Science VIII