Dissolve Solution A very fine sieve. The paper holds back the pieces of undissolved liquid, while letting the liquid through. It can be poured and takes the shape of the container it is in. Melt To change from liquid to solid. Solidify Changes from a liquid to a gas. Freeze A material that keeps it shape. Filter To change from solid to liquid. Solid Solid in liquid, or liquid in liquid. Liquid When two materials are totally mixed. Soluble Change of state from liquid to solid, usually at low temperatures. Evaporation A substance that dissolves in water. Condensation When a gas cools to form a liquid.