Leonardo da Vinci's contributions to both art and science are significant because he embodied the Renaissance ideal of a polymath. In art, his masterpieces like the Mona Lisa and The Last Supper revolutionized perspective and realism. His scientific studies included detailed anatomical sketches and explorations in mechanics and aerodynamics, laying groundwork for future innovators. Da Vinci's method of using observation and experimentation bridged the gap between art and science, impacting multiple disciplines and encouraging a holistic approach to discovery.