UPSC 2013 CDS 2 GK Paper

By mechanism of diffusion, scent spread all over the room if the lid isopened. Diffusion is a physical process where molecules of amaterial move from an area of high concentration (where there are many molecules) to an area of low concentration (where there arefewer molecules). Diffusion usually happens in a solution in gas or in a liquid. On opening lid, the scent diffuses to area of low concentration.