Diffusion is the process of movement of particles from a region of higher concentration to a region of lower concentration. It occurs in both solids and liquids. Here are two examples of diffusion:

1. Perfume spreading in a room
When we spray perfume in a room, the perfume particles spread out and move from a region of higher concentration (near the source of the perfume) to a region of lower concentration (away from the source of the perfume). The process of diffusion continues until the concentration of particles is uniform throughout the room.

2. Oxygen entering blood cells in the lungs
When we breathe in, oxygen from the air enters our lungs. The oxygen molecules diffuse from the region of higher concentration (in the air) to the region of lower concentration (in the blood cells). Similarly, carbon dioxide from the blood cells diffuses into the air in the lungs, where its concentration is lower.

In both these examples, diffusion occurs due to the random motion of particles. The particles move in all directions, but the net movement is from a region of higher concentration to a region of lower concentration. Diffusion is an important process in various natural and industrial processes, such as osmosis, respiration, and separation techniques like chromatography.

Examples of Diffusion. Perfume is sprayed in one part of a room, yet soon it diffuses so that you can smell it everywhere. A drop of food coloring diffuses throughout the water in a glass so that, eventually, the entire glass will be colored.