Leonardo da Vinci designed water-wheel mechanisms to produce continuous rotary motion from moving water.
Water wheels were not Leonardo's invention; they had been used for centuries in mills. His contribution was to study and refine their mechanisms, including arrangements of gears, buckets, channels, and transmission systems. The goal was to convert the force of flowing or falling water into useful continuous movement.
Leonardo's notebooks contain detailed mechanical studies of water-powered devices. He considered how water should enter a wheel, how motion could be transferred, and how gears could drive machinery. These designs connected hydraulic engineering with his wider work on mills, pumps, and automated mechanisms.
A water wheel should not be confused with a modern turbine. A wheel commonly receives force through paddles or buckets, while a turbine is designed around fluid flowing through blades. Leonardo did not create a steam engine, and his water-powered studies belong to the development of preindustrial mechanical engineering.