Hermann von Helmholtz (1821-1894) was a German physician and physicist known for his contributions to various scientific fields, including thermodynamics, optics, and physiology. He is famous for formulating the law of conservation of energy, which states that energy cannot be created or destroyed, only transformed from one form to another. Helmholtz also made significant advancements in the study of sensory perception and auditory physiology. His work on the Helmholtz resonator helped explain how sound waves resonate in different environments, influencing both music and acoustics. His interdisciplinary approach laid the groundwork for modern scientific research.