U3Listening 3.mp3: Experts believe that fireworks were invented in China, in the 2nd century BC. There is a well-known story about a Chinese cook ___1___ fireworks thousands of years ago. He simply mixed 3 routine kitchen ingredients—saltpeter, ___2___ and charcoal. By mistake he ___3___ these three. He also realized that if this is burnt in a bamboo shot, there is considerable ___4___. Initially these were used for fun. Later on it was observed that the sound these explosions created may work for ___5___ evil spirits. Gradually, it came to be used for ___6___ occasions like weddings, religious ceremonies and to celebrate victory and achievements. It was later on that Chinese came to know that this powder could be used as rocket ___7___. This is called a pyrotechnic composition. There is another ___8___ of the incident, Li Tian lit a bamboo tube which was filled with gunpowder and scared off the ___9___ of an evil dragon which a prime minister to the king of the Tang dynasty had killed. The ghost came back to ___10___ him but was ___11___, thanks to Li Tian. He was called the founder of fire ___12___ for this and an incident which happened in ancient China. The Chinese got to know that the gunpowder could also be used as ___13___. This led them to experiment with tubes filled with gunpowder, which were ___14___ to arrows and shot using bows. Another major step came when it was observed that the bamboo tubes filled with gunpowder gave the desired impetus even without ___15___ launching them. This is how the concept of the rocket came into being. There was a Kai keng battle, in which the Chinese used this against the Mongolians. After this battle, in around 1232, the Mongols started producing this on their own. They even sold it to other regions.