sentences: a spoon sometimes is made of metal & metal is a thermal / thermal energy conductor ->  a metal spoon is a thermal conductor  a hot substance is a source of heat & soup is a kind of substance ->  hot soup is a source of heat  hot soup is a source of heat & a metal spoon is placed in a pot of hot soup ->  the hot soup will be a source of heat for the metal spoon  a metal spoon is a thermal conductor & the hot soup will be a source of heat for the metal spoon & if a thermal conductor is exposed to a source of heat, then thermal conduction will make the thermal conductor become hot -> the metal spoon will be heated up by thermal conduction