Mohist classics believe that matter has the smallest unit, which is called "end". Finite objects have finite separability, while end has non-semi (inseparability). The original meaning of atom in western atomism is "unbreakable", which is similar to "final". It can be seen that Mozi put forward the same idea as leucippus's atomism in ancient Greece in the 5th century BC.
In mechanics, Mo Jing thinks that "strength is the exciting reason for punishment" and "strength is heavy". Secondly, harmony and courage are also important. " "Minute" can be understood as from static to dynamic, from slow to fast punishment "refers to tangible objects. It is considered that force is the reason for the acceleration of tangible objects, and weight is also a force. The falling and lifting ("harmony") of an object are all situations in which acceleration is generated under the action of gravity.
The Mohist Classic studies the ups and downs, saying: "The punishment (shape) is large, but shallow, which is called balance." In other words, the part of a large object that sinks into the water is shallow because the weight of the object is balanced by the buoyancy of the water. This shows that Mohism has realized that buoyancy is related to the volume of an object.
Mohist classics have discovered the principle of lever balance. In the Mohist Classic, it is called "heavy" in the canon and "heavy" in the hanging. One side of the fulcrum is called "Mark" (arm of force) and the other side is called "Ben" (heavy arm). If both sides are balanced, the lever must be horizontal. In a balanced state, if one side has weight, it will definitely make this side sag. At this time, in order to restore the balance between the two sides, it is necessary to move the fulcrum, shorten the "book" and lengthen the "table". However, if the "book" is short and the "watch" is long, if both sides are weighted equally, then one end of the "watch" will definitely sag. Mohism mastered the law of leverage two centuries before Archimedes.
In optics, Mo Jing recorded the earliest pinhole imaging experiment in the world: a small hole was opened in the door of a darkroom. When a person stood outside the room facing the hole, an inverted figure appeared on the wall opposite the room. The Book of Mohism explains: "If the people in Jingguang are bright, the people under them are also high, and the people above them are also high." It means: because light travels in a straight line like archery, the lower part of the human body blocks the light coming from the straight line and enters through the small hole, forming a shadow on it, while the upper part of the human body blocks the light coming from the straight line and passes through the small hole, forming a shadow below and becoming a reflection. This is the first scientific explanation for the straight-line propagation of light.