Around 1100 years ago, the Chinese invented an early version of gun powder to create fireworks for celebrations. This gun powder was rolled tightly in paper and the ends were twisted. When these crude firecrackers were lit, they would explode with a loud bang and a flash.
Eventually, someone noticed that if one end was not twisted as tightly, that sometimes gases created by the explosion would escape, sending the firecracker flying in the opposite direction. It wasn’t long before people began experimenting with leaving one end unwrapped to create rockets that flew through the air before exploding. These early exploding rockets were very unreliable and required a great deal of experimentation to improve.