The show courted mild controversy when it emerged that at least one of the experiments was faked by a pyrotechnics department. The alkali metals are known to react rapidly with water, producing hydrogen gas and energy, with potentially explosive results. An experiment was set up to demonstrate how these metals reacted by dropping them in water, with the expectation that the heavier alkali metals would be more potent. Lithium, sodium, potassium and rubidium reacted with increasing potency. However caesium (the heaviest of the alkali metals commonly available) simply sank to the bottom of their "tank" (a bath) before it could react significantly, which was far less dramatic than the other reactions suggested. The producers had the bath wired with explosives and blown to pieces, and presented this instead. According to a statement issued by the production company, they frequently used pyrotechnics in this way.