Key notes for Chapter- Matter in Our Surroundings, are: Matter: Anything that occupies space and has mass is called matter. It exists in the form of five basic elements, the Panch tatva – air, earth, fire , sky and water. For example: Chair, bed, river, mountain, dog, tree, building, etc. Characteristics of matter: Matter is made up of small particles called atoms. These particles are too small to be observed with naked eye. These particles are constantly moving constantly. These particles have spaces between them. Particles of matter attract each other because of the force of attraction. Diffusion: Particles of matter intermix on their own with each other. They do so by getting into the spaces between the particles. This intermixing of particles of two different types of matter on their own is called diffusion.  Applications of Diffusion: Dissolving a solid in a liquid: When a crystal of potassium permanganate is placed in a beaker of water, the water  slowly turn purpl...