Rust is a reddish-brown layer that forms on objects made of iron or steel. Rusting slowly changes the metal and makes it weak and flaky. Materials like plastic, glass and gold do not rust.
What causes rust
Iron rusts only when it touches both water and oxygen from the air. If either one is missing, rust cannot form. That is why an iron nail in a dry, sealed jar stays shiny, but a nail left outside in the rain rusts quickly. Salty air near the sea makes rusting happen even faster.
Key idea
Rusting needs iron + water + oxygen. Remove one, and rust cannot form.
Preventing rust
We stop rust by keeping water and air away from the metal. A coat of paint, oil or grease forms a barrier so water and air cannot reach the iron. Coating iron with zinc, called galvanising, also protects it. Keeping tools dry and wiping them after use helps them last much longer.
Remember
- Paint, oil or grease the metal.
- Coat it with zinc (galvanising).
- Keep iron objects clean and dry.