The particles in solids, liquids and gases all behave in different ways but result in a similar way. They all expand when heated up.
The particles in solids vibrate more and knock against each other when heated and result in taking up more space. The property of solids (metal) expansion makes it possible to join two metal pieces without welding.
Particles in liquids move around each other some more, vibrate quickly and also result in taking up more space.
The particles in gases move freely in all directions and take up more room too. When heated, they move very quickly and move about more.