Book 1, Question 111
Why Does Metal Rust? Iron, Oxygen and Water!
Rust does not happen by magic. Iron meets oxygen and water, and they join to make iron oxide, that flaky orange stuff we call rust. A shiny nail is smooth, shiny and strong, while a rusty nail is rough, dull and brittle. The page calls rust a slow burn without flame. With a grown-up, leave a wet nail and a dry nail for a day and see which one changes.
From the book
Page from A Million Whys Book 1
More fun facts
- Rust forms when iron is exposed to both water and air. Take away either one and it won't rust.
- Salt water makes iron rust faster.
- Rust is a weak, flaky brown material, much weaker than the iron it came from.
- Oiling bike chains, greasing nuts and bolts, and painting car bodies all stop rust by keeping water and air away.
- Food cans are made of steel coated with a thin layer of tin to protect them.
- Galvanising coats iron or steel with zinc. The zinc reacts first, so it protects the iron underneath.
- Metals like zinc and magnesium are called sacrificial metals because they corrode instead of the iron.
Questions kids ask
How can you stop iron from rusting?
Keep water and air away with oil, grease, paint or plastic, or coat it with zinc.
Does salt make rust worse?
Yes. Salt water speeds up rusting.