Explain the term 'amalgam'. Give an example of its use.

An amalgam is an alloy of mercury with one or more other metals. Mercury is liquid at room temperature, and when it mixes with other metals, it forms a solid or liquid alloy. A common example of its use is in dental fillings, where silver amalgam (an alloy of mercury, silver, tin, and copper) was traditionally used to fill cavities due to its malleability when wet and hardness when set.