Characteristics of particles of matter | Matter in our surroundings | Chemistry | Khan Academy

Particles of Matter Have Space Between Them00:00:00

When a stone is submerged in water, the water level rises. However, when salt is dissolved in water, the water level does not rise. This is because salt particles are much smaller and occupy the spaces between the water molecules, demonstrating that particles of matter have space between them.

Particles of Matter are Continuously Moving00:01:17

Several examples illustrate continuous particle movement: the spread of incense smell, the dissolution of potassium permanganate in water, the mixing of food coloring in water, and the dancing of dust particles in sunlight. This movement, especially in liquids and gases, is random and a result of kinetic energy. Particles vibrate even in solids, and this vibration increases with temperature.

Diffusion: Intermixing of Particles00:03:35

When substances like potassium permanganate or incense particles mix with water or air, they occupy the spaces between the other particles. This intermixing of two different types of particles is called diffusion, and it occurs spontaneously.

Particles of Matter Attract Each Other00:04:30

Water collecting on the floor or a raindrop forming a spherical shape demonstrates that particles of matter attract each other through intermolecular forces. These forces pull the particles together.