The Eötvös experiment is a scientific test designed to measure the equivalence principle, which states that gravitational mass and inertial mass are equivalent. Conducted by Hungarian physicist Lóránd Eötvös in the late 19th century, the experiment involved a torsion balance to compare the gravitational attraction of different materials. Eötvös's findings showed that the gravitational force acting on various substances was consistent, supporting the idea that all masses experience gravity equally. This experiment has significant implications for our understanding of gravity and has influenced modern physics, including theories related to general relativity.