Memory Game MATTER AND ENERGY, CALP, YEAR 1Online version Listen, read and match. by Rafael Rodríguez Pérez Materials can be natural or manufactured. Some materials change their state. Energy can be produced from renewable sources. Pure substances are made of 1 thing. Materials can be rough, smooth, soft, hard, rigid, flexible, transparent or opaque. Energy can be produced from non-renewable sources. Mixtures are made of more than 1 thing.