Few substances in history have had as profound an effect on mankind as gunpowder and yet its discovery was probably an accident! A big bang, for one… Records show that the Chinese were aware of the explosive stuff as early as 300AD. The invention of gunpowder is a bit of a mystery, and so are its ingredients: it was made by mixing sulfur (a yellow stone- hiding deep underground), charcoal (burned wood), and saltpeter (or potassium nitrate) which was the white frosting found on poop that had been given time to settle and get comfortable. As you can imagine, it takes some effort to make gunpowder. But, rulers needed gunpowder. Gunpowder needed saltpeter. And saltpeter needed poop. And so, dukes declared a monopoly on their lands' waste. Until, only 500 years after the Chinese discovered it, we found out why secretions have such an explosive character. It turns out to be caused by microscopic bacteria, which produce the nitrates as byproducts of digestion. The reason why gunpowder explodes is that it burns very fast, and when it burns it releases gases that have a bigger volume than the original powder (similar to how steam is bigger than water is). But the gunpowder from the old days gave off so much smoke that battlefields were literally too smoky to aim. Until, in 1888, Albert Nobel invented a dense smokeless powder explosive called ballistite. And now, is gunpowder about to be replaced?