The rocket is an inexpensive, but effective, piece of engineering that has been around for centuries. One of the earliest forms of rockets was the firework's shell, which is designed to contain a combustible material in order to cause an explosion. This technique was perfected by Chinese engineers in the 10th century and used during celebrations for various celestial events. Rockets were primarily used as military weapons until they became popular with scientists beginning in the late 18th century. Both American engineer Konstantin Tsiolkovsky and German scientist Hermann Oberth developed theoretical designs for rockets with modern materials like steel and aluminum in the early 20th century.
