Engineering materials and heat treatment
Metals such as brass, copper or steel are solid (frozen) at room temperatures but become liquid (molten) if heated to a sufﬁciently high temperature. If they are heated to a high enough temperature they will turn into a gas. On cooling, they will ﬁrst turn back to a liquid and then back to a solid at room temperature. Providing no chemical change takes place
three states by heating and cooling as often as we like.