3 Gunpowder – the explosive reaction of charcoal, sulfur and potassium nitrate

An explosive is a material that releases large quantities of hot gas extremely rapidly, and very violently.

Indeed, the following quote is attributed to Roger Bacon (Figure 1), a Franciscan monk who introduced gunpowder (also known as blackpowder) to Europe in the 13th century:

Figure 1 Roger Bacon

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Portrait image of Roger Bacon

Figure 1 Roger Bacon

Gunpowder consists of sulfur and charcoal (fuels), mixed with potassium nitrate (an oxidiser – a type of chemical which a fuel requires in order to burn).

The basic mixture was, in fact, originally discovered by eighth century Chinese alchemists. However, Bacon experimented with the relative proportions and undertook a detailed scholarly investigation into the explosive. As a consequence he incurred the wrath of the Church, and suffered long term imprisonment for his efforts. However he did manage to preserve his recipe for blackpowder in the form of an anagram (Figure 2).

Figure 2 Bacon's anagram for the composition of gunpowder

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This image shows a few lines of written text from Bacon's work, which are supposed to contain coded information about the gunpowder recipe.

Figure 2 Bacon's anagram for the composition of gunpowder

In fact on line two, you can make out the word ‘saltpetre’, the old fashioned name for potassium nitrate.