The Propeller

Archimedes designed a screw which could carry water up a hill by cranking a handle. Leonardo da vinci used this screw to provide lift for a hand held helicopter but Leonardo never actually built this machine so it is unknown if it would have worked. Steamboats used paddle wheels to propel them through the water which is called thrust. Paddle wheels are large wheels that have paddles on them so that when the wheel turns it forces the water back and the ship forward. The paddle wheel was not the best because a large wave or lot of wind could tip the ship a bit making the paddle wheel come up out of the water and no provide thrust. A man named Francis smith made a Leonardo propeller but instead of using it to fly Smith used it on a boat. The propeller was lighter than the paddle wheel making captains have to pay less for fuel and it would be under water both making it less easy to lose thrust and less easy for enemies to destroy your source of power. Mr. Smith advertised all these benefits to the British navy by using all those benefits in an actual test of the ship on the sea. They decided they liked it, bought it from him and used it in their ships and scientists started making improvements on it and eventually used them in airplanes and other air and water crafts. Tickets to ships got cheaper and more people used ships more often