Coulomb's main contributions are torsion balance experiment and Coulomb's law. Coulomb's law makes the study of electromagnetism from qualitative to quantitative, which is an important milestone in the history of electromagnetism. Cullen studied at Mazar-e-Lan College and French College in Paris, and served in military service. 1774 was elected as an academician of the French Academy of Sciences. From 65438 to 0784, he served as a supervisor of the Water Supply Committee and later as a supervisor of the Map Committee. 1802, Napoleon appointed him as a member of the Education Committee. 1805, he was promoted to director of education supervision.
1773 published a paper on the strength of materials, and the method of calculating the stress and strain distribution on objects is still in use today, which is the theoretical basis of structural engineering. 1777 began to study static electricity and magnetism. At that time, the French Academy of Sciences offered a reward for improving the magnetic needle in the navigation compass. Coulomb thinks that the magnetic needle supported on the shaft will inevitably bring friction, and puts forward to hang the magnetic needle with fine hair or silk thread. In the study, it was found that the torsion of the wire was proportional to the angle of the needle, so that the electrostatic force and magnetic force could be measured by this device, which prompted him to invent the torsion balance. He also established the law of elastic torsion according to the fact that the torsion of silk thread or metal wire is proportional to the rotation angle of the pointer. He analyzed the friction force according to 1779, put forward the scientific theory about lubricant, found the relationship between friction force and pressure in 178 1, and expressed the laws of friction, rolling and sliding. Design underwater operation method, similar to modern caisson. From 1785 to 1789, the electrostatic and magnetic forces were measured with a torsion balance, and the famous Coulomb's law was derived.