Alchemy

Alchemy is a rare art for permanent change, transferring properties of one concept into another. While philosophy has done this since time immemorial, Alchemy performs this on a material level.
While some may confuse potions and Alchemy, the difference lies in permanence. Alchemy enacts permanent changes on a material scale, whereas potions will make temporary changes that may assist the permanent changes to occur. Likewise transfiguration will make temporary changes to an object before the object's natural resistance forces reversion, but Alchemy will take the changes on a fundamental level. In essence, while those familiar with muggle physics will make connections, it is a way to create lasting materials without undergoing the cost of processing.
One example given is the Bubblehead Charm. While known as a charm, it performs a function of Alchemy by concentrating gaseous oxygen from its surroundings, therefore allowing the caster's target to be enveloped by this gas, even under water.