A small pair of pliers has a lot of knowledge! I've seen a lot

When it comes to pliers, we may be familiar with it. After all, it is a popular tool and almost every family must have it! But if you go a little deeper, you may not know the history of pliers. In addition, have you discovered the physics theorem contained in pliers?
Our traditional pincers originated in Europe. More than 1000 years ago, people began to use iron. Due to the high temperature in the process of casting iron, people could not take out the iron from the furnace in time, so they invented pincers to hold hot iron pieces. The shape of pincers has hardly changed, and they have remained until today.
In the development of contemporary society, due to the continuous improvement of people's demand, the types of pliers are gradually enriched. According to incomplete statistics, the number of universal pliers has grown to more than 100.