Book 3, Question 15
Why Do Rockets Need Fire?
A rocket burns fuel and throws hot gas out of the bottom. Every action has a push back, so when the gas goes down, the rocket goes up! It even works in empty space.
From the book
Page from A Million Whys Book 3
More fun facts
- There is no air in space, so rockets must carry their own oxygen, or a substance called an oxidizer, to burn their fuel.
- Jet engines suck in air, but rockets have no air intakes at all.
- Fuel and oxidizer burn inside a combustion chamber, making hot, expanding gas.
- The gas pushes harder on the top of the chamber than the bottom, so the rocket moves up.
- Some of the earliest rockets were Chinese fire-arrows, which were not very reliable.
- Robert Goddard launched the world's first liquid-fuel rocket in 1926.
- The first stage of SpaceX's Falcon 9 rocket has nine engines.
Sources: Smithsonian, National Geographic, NASA, NASA Science
Questions kids ask
How can fire burn in space with no air?
Rockets carry their own oxygen or another oxidizer with them, so the fuel can burn even where there is no air.