Which propulsion type uses blades to create thrust while converting rotational motion?

The propulsion type that uses blades to create thrust while converting rotational motion is the propeller. A propeller consists of multiple blades that rotate around a central shaft, and as they spin, they push against the surrounding fluid—whether air or water—creating thrust. This process effectively converts the rotational energy from the engine into linear motion, allowing an aircraft or a boat to move forward.

In the context of other propulsion types, the sail harnesses wind power for forward motion by utilizing the aerodynamic lift created by its surface, rather than using blades for thrust. A water jet relies on the high-speed expulsion of water to create thrust, employing a different mechanism of propulsion that does not involve rotating blades. Manual propulsion typically involves human effort, such as rowing or pedaling, which also does not utilize rotational blade motion to generate thrust.

Thus, the unique design and functioning of propellers distinguish them as the correct answer for the method that uses blades and converts rotational motion into thrust.