Science is the study of nature and its application to mankind, Chemistry is a branch in which we study about the composition, structure and properties of matter and the changes which matter undergoes by the interaction of its various forms. Our universe is composed of matter and energy. Matter may, thus, be defined as anything that occupies space, possesses mass, offers resistance and can be felt by one or more of our senses. Some examples mass, offers resistance and can be felt by one or more of our senses. Some examples of matter are water, air, metals, plants, animals, etc. Thus, matter has countless form. Matter can be classified into different categories depending upon its physical or chemical nature.

The amount of matter present in any object is called its mass and the forces with the object is pulled towards the centre of earth is its weight. Closely related to matter is energy. It is defined as the capacity of a body to do work. Energy is different from matter because it cannot be seen, touched or smalt. However, it can be observed by its effect on matter.