1. Measurement is basically a process of comparison and involves two things: a number and a unit.

2. The unit of physical quantity is a standard value of it in terms of which other quantities of that kind are expressed.

3. There are seven fundamental quantities amount of subsances namely length, mass, time, temperature, amoung of substances light intensity and electric current.

4. There are seven SI units and a number of derived units.

5. A metre scale is used to measure large lengths. To measure small lengths, we use vernier callipers or screw gauge.

6. Area is measured in square metre (m2) and graph papers are used for estimating the areas of irregular figures.

7. The total space occupied by any piece of matter is called its volume. It is measured in cubic metres (m3). The unit ‘litre’ is also used to measure the volume of liquids.

8. Standard measuring vessels are used to measure volumes of liquids like milk, kerosene oil, mobile oil at petrol pumps, etc.

9. In the laboratory, we use graduated cylinder and an overflow can to measure the volume of large irregular bodies.