Properties of Matter

The defining characteristics between the phases of matter are the kinetic energy of the molecules and the density of the particles to one another.

Take water for example. Below 0°C water is a solid, ice. Above 0°C but below 100°C,
you will have liquid water. When water is heated above 100°C, it becomes a gas.


In ice, solid water, the molecules are so tightly packed they are fixed in a rigid structure.


As a liquid, water molecules can slide past one another in a smooth motion, but they remain touching. This is why water will conform to the shape of its container but still keeps a constant volume.


Water vapor has high kinetic energy so the molecules move very quickly. There is a great deal of space between the particles so they shoot off in every direction, spreading farther and farther apart until they fill the entire room.