torsion balance

A torsion balance is a precision instrument used to measure very small forces or differences in force. It consists of a lightweight horizontal bar or wire suspended by a thin fiber or wire. When a force acts on objects attached to the bar, it causes the bar to rotate slightly. The twisting of the fiber provides a restoring force, and the amount of rotation indicates the strength of the force applied. Torsion balances are often used in scientific experiments, such as measuring gravitational forces or detecting tiny forces like magnetic or electrical interactions.