Book 6, Question 103
Why Do Big Ships Have Such Small-Looking Propellers?
A big ship's propeller looks small next to its huge hull. But up close, its blades can be taller than a person! It pushes water backward, and the ship moves forward.
From the book
Page from A Million Whys Book 6
More fun facts
- A ship's propeller pushes water in much the same way an airplane's propeller pushes air.
- Ship propellers and airplane propellers look quite different, but both work using the same idea of lift.
- Small bow thrusters in the front of a ship push it sideways near docks.
- Some cruise ships have a giant motor and propeller hanging under the back on a swivel that turns all the way around, so the ship can be driven in any direction.
- As early as 1800, a man named Shorter got a patent for pushing boats with a screw propeller.
- The Wright brothers' 1903 Flyer had two propellers driven by bicycle chains.
Sources: Smithsonian, NASA, Scientific American, Scientific American, Scientific American
Questions kids ask
What helps a big ship move sideways?
Small bow thrusters in the front push it from side to side near docks.