When ice is heated, particles vibrate faster about a fixed point causing particles to move further apart and so ice expands. When particles gain sufficient energy to overcome strong forces of attraction, they move out of their fixed position and can slide over each other in a continuous random motion – solid has melted. Particles in liquid have energy to move around but are still close to each other and do not have enough energy to overcome the forces that hold them close to each other. If more heat’s supplied, particles move faster until they have enough energy to overcome the forces of attraction. More heat means more kinetic energy between the particles. The more heat given, the more they collide successfully. Particles escape the liquids surface and move around in continuous rapid motion – the liquid has boiled . It turns to gas. Therefore, the phase changes from ice to gas.
