rust

Everyday

1. Rust is the reddish-brown, flaky coating that forms on iron or steel when it gets wet and meets air. tree →
2. To rust means to become covered with rust. tree →
3. Rust is also a reddish-brown colour. tree →

In the lessons

In science rust is a chemical change: iron reacts with oxygen and water, so it is a classic example of a change you cannot undo. In everyday life it makes bikes, nails and gates weak; paint and oil stop it. Phrases: «rust away», «covered in rust», «rust-proof», «rusty».

Examples

• My old bike chain is covered in rust. tree →
• Iron rusts when it is left out in the rain. tree →
• Paint stops the gate from rusting. tree →
• Rust made the metal weak and it broke. tree →
• Be careful with rusty nails; they can cut you. tree →
• The car had rust on its doors. tree →
• Salt water makes metal rust faster. tree →
• Gold never rusts. tree →
• Others polished the blade until all the rust was removed and it glistened like burnished silver. tree →

Note

Uncountable: some rust, not «a rust». Adjective: rusty. Only iron and steel truly rust; other metals tarnish or corrode. Safety: a cut from a rusty nail needs cleaning and maybe a tetanus shot — the danger is germs (tetanus), not the rust itself.