The Chinese invented gun powder. Although gun powder developed over time, the first documented mention of the substance was in the Han dynasty by Wei Boyang ("Gunpowder"). Historians believe that the chemical mix was originally discovered as a medicine meant to give the user eternal life; however by 300 AD, a Chinese scientist , Ge Hong, had experimented with the ingredients and written a recipe, describing the explosive effects ("Gunpowder"). Eventually by the Tang Dynasty, emperors were using gun powder for fireworks and then eventually as a weapon, making small cannons out of bamboo tubes ("Four Inventions").
Europeans were first introduced to gunpowder via trade on the Silk Road from China; they were both impressed and amazed, not only by the amazing fireworks displays which would become highly sought after trade goods, but also by the destructive potential of gun powder.
"Gun Powder in Ancient China." History for kids. Dr. Karen Carr. Web. 23 Jan. 2013.
"Four Inventions of Ancient China." Travel China Guide. Travel China Guide. Web. 23. Jan. 2013.