1.2 understand how the interconversions of solids, liquids and gases are achieved and recall the names used for these interconversions

- Solid -> Liquid
When the solid is heated, the particles gain energy causing the particles to vibrate more. As you should know this weakens the forces that keep the solid 'solid'. (In 1.1 we talk about how heating solids expands it.) The particles now have enough energy to be free from their lattice - this is called MELTING.

- Liquid -> Gas
When a liquid is heated, the particles simply gain more energy and hence move even faster. Eventually the bonds break which hold the liquid together causing the liquid to turn into a gas - this is called EVAPORATING.

- Gas -> Liquid
When a gas is cooled, some of the particles loose energy, this causes them to come together and for them to create bonds. During this process heat is given out. This is called CONDENSING.

- Liquid -> Solid
When a liquid is frozen, even more energy is lost and more heat is given out. When the particles are frozen, the particles start to travel very slowly and their attractions cause them to place themselves in a solid lattice causing them to bond. This is called FREEZING.