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