Solids, liquids and gases are made of particles. When the substance's temperature increases, the particles move faster.
:memo:The particles of a solid are held next to each other. They vibrate about their fixed positions and keeps its own shape
:memo: A liquid's particles are in contact with each other, but they have some movement, meaning the liquid has no shape, and can flow.
:memo: A gas's particles move about more random than liquids. They are much further apart, meaning the density is far lower.