Four greatest breakthroughs in China

From very little, I have known that China has four greatest breakthroughs: compass, gunpowder, photocopy technique, and papermaking. These four things make me be proud as a Chinese. I will introduce two of these four breakthroughs.
The first breakthrough I want to introduce is compass. Before the invention of the compass, people decided the directions mainly by the sun, the moon, and other celestial bodies, or landmarks such as mountains, stones, and trees. But, these methods had their restrictions: you cannot depend on a celestial body when the weather is bad, for instance, during rain, fog, and overcast days. While using landmarks only work within a small area. The first model of compass occurred in the Warring States Period in old China. It was called “Si Nan”. It was a natural magnet and it was very heavy. That was why people could not use this widely at that period. Gradually, people found the way to make artificial compass and it spread all over the world quickly.
The second one I will introduce is photocopy technique. Nowadays, people use photocopy technique very often. Especially for students and office workers, they use it almost everyday. Before the invention of this technique, the diffuseness of culture mainly depended on handwriting. Hand-writing copy costs lots of time and it was also easy to make some mistakes. A Chinese inventor called Bi Sheng invented this technique. At the very beginning, he carved lots of characters on a big wooden board, then he smeared full of ink on this board, and in the end he put a paper on this board. In this way, the new copy of the characters in the board occurred. This was the origin of the modern photocopy technique.
Here are the pictures of these two breakthroughs and the inventor of printing-Bi Sheng. Enjoy them~