Have you ever observed the change in colour and texture of salt when added to a curry, but it’s composition never changed? Why do we cry while chopping onions? How is the soap we use for cleaning made? How is vinegar used as a preservative? Most of the changes we feel or observe in our surroundings are the result of chemical reactions. It can be both physical and chemical. The toothpaste we use to brush our teeth to the table salt we add for food are all a part of chemistry. Chemistry is a vast field of study which we touch, feel, smell and even eat in our everyday life. Interesting isn’t it? We ourselves are the products of chemistry since our body is made of minerals and chemicals. The water we drink, the food we eat, the medicines we take are all a part of chemistry. Carbon, hydrogen, oxygen and nitrogen are considered as the four important elements of living system. The air we breathe in has a mixture of elements.