The Han dynasty fell because of unrest, revolt and rebellion of their people. Eventually the Empire weaken and fell.
Rise of Song dynasty
After the fall of the Han dynasty, China split into three main kingdoms. The Sui, Wei and Shu-Han. After the kingdoms weakened from fighting eacho other, Li Yuan conquered them and founded the Tang dynasty and reunifed China.
The tangs invented gunpowder represented by the cannon and white powder, pottery glaze represented by the pot and the printed press represented by the scroll.
Song vs Tang inventions
After the Tang dynasty fell, fighting broke out and some people wanted to have a daoist kingdom or dynasty after the Tang fell, but some people wanted confucianism kingdom or dynasty. eventually the Song dynasty was founded and they once again reunifed china.
The songs had many inventions. They introduced a drought resistant typre rice that would help the pople, made miliary advancement such as the crossbow and gunpowder propelled arrows. They also invented the first mechanical clock.
The Tang did not invent much but paved the way for some Song inventions. The songs invented many things like the crossbow made the great wal of china and helped make the way for the first mechanical clock.