Solid

• The particles are packed closely together, in a regular pattern.

• each particle is in close contact

• Because the particles are so tightly packed, they cannot move around. However, they do move a bit. They can vibrate about a fixed position. The hotter the solid, the more they vibrate.

Liquid

• The particles are packed slightly less closely together than in a solid. The particles are arranged randomly rather than in a fixed pattern

• Because the particles are slightly less tightly packed than in a solid, they can move around. So the particles are both vibrating and moving from place to place. The hotter the liquid is, the faster its molecules move.

Gas

• The particles are widely separated from one another. They are no longer in contact, unless they collide with each other. In air, the average separation between the particles is about ten times their diameter.

• The particles move freely about, bouncing off one another and off the walls of the container. In air at room temperature, the average speed of the particles is about 500 m/s and this increases with temperature.

Brownian Motion

• The Brownian motion is one of the way to prove the kinetic theory of particles as, one of the scientist was test pollen grains with a microscope

• He observed they were moving, he tried this with dust, he got the same result, this was because the particles collided each other and started moving in a high speed

Reasoning Facts Using The Kinetic Model

• Liquids take up the shape of their container because their particles are free to move about with the liquid.

• Gases fill their container because they use their particles to move about with complete freedom.

• Gases diffuse (spread out) from place to place, for example, we can smell perfume across the room. The perfume particles spread about because they are free to move.

• Dissolved substances diffuse throughout a liquid. Sugar crystals in a drink dissolve and molecules spread throughout the liquid, carried by the mobile particles. In a hotter drink, the particles are moving faster and the sugar diffuses more quickly.

• Most solids expand when they melt. The particles are slightly further apart in a liquid than in a solid.

• Liquids expand a lot when they boil. The particles of a gas are much further apart than in a liquid. We can think about this the other way round. Gases contract a lot when they condense. If all of the air in the room you are now in was cooled enough, it would condense to form a thin layer of liquid, two or three millimeters deep, on the floor.

Attractive Force

• Matters like solid, liquid and gas have particles that are together, this is because they have forces within the particles that make them attract