Before chemistry was a science, there was alchemy. One of the supreme quests of alchemists was to transmute (transform) lead into gold.

Lead (atomic number 82) and gold (atomic number 79) are defined as elements by the number of protons they possess. Changing the element requires changing the atomic (proton) number. The number of protons in an element cannot be altered by any chemical means. However, physics may be used to add or remove protons and thereby change one element into another. Because lead is stable, forcing it to release three protons requires a vast input of energy, so much so that the cost of transmuting it greatly surpasses the value of any resulting gold.

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