Gunpowder

Gunpowder was an explosive substance that was used mostly in warfare, in weapons such as cannons, to explosively propel objects. It was used on Earth, and on some primitive planets such as Ribos. (DW: The Ribos Operation) One of the most notable uses of gunpowder was in 1605, where Guy Fawkes and his anti-parliament plotters attempted to blow up the Houses of Parliament by placing several barrels of gunpowder beneath it. (MA: The Plotters)

While searching through a manor that was near the Terileptil escape pod, the Doctor and his companions discovered gunpowder, power packs and the mark of a high energy weapon. The gunpowder was residue from a fight between the owners of the manor and Terileptils. (DW: The Visitation)

In order to fight Windigos, the Eighth Doctor created flash-charges. These were made by adding iron fillings to gunpowder. The light created upon the gunpowder's detonation deterred the Windigos. (DWM: Bad Blood)