Among the given options, heating of a platinum crucible is an example of physical change. The following explanation presents the apt justification: 1. A physical change is reversible, whereas a chemical change is not. For example, the freezing of water would be a physical change because it can be reversed, whereas the burning of wood is a chemical change – we can't 'unburn' it. 2. A physical change is a change in which no new substance is formed; a chemical change results in the formation of one or more new substances. Again, consider the previous example: Freezing water into ice just results in water molecules which are 'stuck' together – it is still H2O, whereas burning wood results in ash, carbon dioxide, etc. – all new substances which were not there when we started.