Experimental design of weak magnetic fields measurement based on torsion balance

Recent advances in biophysics, geophysics and fundamental physics have collectively demonstrated the importance of precision magnetometry. Previous studies have demonstrated that precise magnetic field measurements typically rely on complex and expensive precision instruments. In this work, we introduce a torsion balance based magnetometry system, where its high precision primarily stems from the torsion balance’s extreme sensitivity to minute torques. Using geomagnetic field measurement as an example, we experimentally verify the system’s response to weak fields and discuss its accuracy limit. The results show that this design enables accurate weak-field measurements (nT lever) in a simple and low-cost manner, which is not only expanding the list of laboratory exercises for students of physics-related specialties, but offers new information relevant to the precise measurement of weak magnetic fields.