The development of chemistry is based upon the systematic approach of the scientists in carrying out different experiments. Scientific theories, inferences and generalizations are made on the observations recorded. The quantitative information involves the measurement of one or more quantities. These measurements are often used in calculations to obtain other related quantities. The ability of a chemist to measure properties as accurately as possible depends upon his skill and the degree of accuracy of the instrument.
Chemistry is largely an experimental science. It deals with physical things that can be measured. A number of devices are used in laboratories to make simple measurements such as, a metre rod measures length; a physical balance measures mass; burette, pipette, graduated cylinder etc. measure volume; thermometer measures temperature and so on. Any measured physical quantity consists of two parts:
For example, if one measures the length of a wall as 24.8 m, then 24.8 represents the numerical value and 'm' (which stands for metre) represents the unit.
