Chemistry
At some point, a chemist wanted to know the change of the encounter between Potassium Chloride and Lead II Acetate. Then he took the two and placed them in one place according to law.

At the beginning, the two were still safe. Not long after, I saw that they gradually changed, and there seemed to be something in the liquid, with a specific color state. The scholar stared, thinking about the reason for this change in his heart.

Over time, analyze the results, and know that the two are factored, resulting in a new substance. During this process, the ions change, and they become something else. The scholar recorded his feelings in detail, thinking that the information for future study would be more clear in the principles of chemistry.