--- title: Rust: iron's slow fire — a lesson of Mova's school · trees and pragmatics description: «Rust: iron's slow fire», a lesson of the chemistry course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Leave a bike out in the rain all winter and its chain and bolts turn orange-brown and flaky. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Chemistry](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/) / Rust: iron's slow fire # Rust: iron's slow fire Lesson 13 of the chemistry course of Mova's primary school: 19 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/chemistry/13-rust-irons-slow-fire/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/0/) — Leave a bike out in the rain all winter and its chain and bolts turn orange-brown and flaky. - [1](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/1/) — That orange stuff is rust, a brand-new substance, not dirt that has landed on the metal. - [3](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/3/) — Take away either one, the water or the oxygen, and the iron hardly rusts at all. - [4](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/4/) — Rusting is a very slow cousin of burning: iron and oxygen join and give out a little heat. - [5](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/5/) — In a hand-warmer pack the iron is a fine powder, so it rusts fast enough for you to feel the warmth. - [6](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/6/) — Rust is flaky and falls away, so fresh iron underneath is uncovered and rusts next. - [7](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/7/) — That is why paint, a coat of zinc or a pinch of chromium mixed into the steel are used to keep air and water off. - [8](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/8/) — Other metals change too: copper slowly grows a green coat, like the Statue of Liberty, and that coat stays put and protects the copper underneath. - [9](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/9/) — Rust forms when iron or steel joins with oxygen and water; it is a new substance, so rusting is a chemical change. - [10](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/10/) — Iron in dry air, or in water with no air in it, hardly rusts; it needs both oxygen and water. - [11](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/11/) — In the classic three-nails test, the water is boiled to drive out air and oil is poured on top to stop air getting back in; only the nail in ordinary water with air rusts well. - [12](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/12/) — Salt from sea spray or from gritted winter roads makes iron rust faster, so cars and railings by the sea rust quickly. - [13](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/13/) — Rust is flaky and falls off, so it does not protect the iron underneath and rusting can go right through. - [14](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/14/) — Paint stops rust by keeping air and water away; once the paint is scratched, rust starts at the scratch and creeps under it. - [15](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/15/) — Galvanised steel is coated with zinc; the zinc reacts first and "sacrifices" itself, so the iron stays safe even at small scratches, and ships carry zinc blocks for the same reason. - [18](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/18/) — The Statue of Liberty is made of copper sheets; it was shiny brown in 1886 and turned green as a protective coat called patina formed. - [19](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/19/) — Tetanus is caused by a germ in soil and dirt, not by rust; a deep cut from any dirty object can let it in, and vaccination protects you. - [20](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/20/) — Iron is found in rocks mostly joined with oxygen, as iron ore; people heat it with carbon in a furnace to pull the oxygen away and get iron. - [21](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/13-rust-irons-slow-fire/21/) — Mars looks red because its dust contains iron oxide, the same kind of substance as rust. - ← previous: [Fire: what it needs and how to put it out](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/12-fire-what-it-needs/) - next →: [Tarnish and how metals change](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/14-tarnish-and-how-metals-change/) - ↑ back to [Chemistry](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/)