--- title: Olympiad: everyday chemistry detectives ★★★ — a lesson of Mova's school · trees and pragmatics description: «Olympiad: everyday chemistry detectives ★★★», a lesson of the chemistry course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Out of the kitchen and into the house, the garden and the street: these puzzles make you a chemistry detective, reading clue --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/) [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/) / Olympiad: everyday chemistry detective… # Olympiad: everyday chemistry detectives ★★★ Lesson 37 of the chemistry course of Mova's primary school: 20 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/37-olympiad-everyday-chemistry-detectives/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/0/) — Out of the kitchen and into the house, the garden and the street: these puzzles make you a chemistry detective, reading clues on a bike, a spoon, a candle or a kettle. - [1](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/1/) — Most clues point to a few big ideas from the course: what a change needs (rust needs air and water, fire needs fuel, heat and oxygen), what a thing is made of, and whether a change can be undone. - [2](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/2/) — Picture three nails in three jars: one in dry air, one in boiled water under a layer of oil, one in ordinary tap water. - [3](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/3/) — A week later only one is properly rusty, and a detective knows which before looking. - [4](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/4/) — People talk big and small: "my bike's a total pile of rust" may mean three orange spots, while "the kettle's got a bit of fur" may mean a crust as thick as a coin - a detective checks the real size. - [5](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/5/) — These puzzles are for thinking, not trying: fire, cleaning products and batteries are a grown-up's job. - [6](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/6/) — Iron rusts only when it has both oxygen and water; salt from sea spray or gritted roads makes it rust faster. - [7](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/7/) — Paint stops rust until it is scratched; galvanised steel has a zinc coat that protects the iron even at a scratch. - [8](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/8/) — 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. - [9](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/9/) — Silver turns black from sulphur gases, which eggs give off; gold hardly ever tarnishes, and copper slowly grows a green coat called patina. - [10](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/10/) — Fire needs fuel, heat and oxygen; a candle under a jar goes out when the oxygen runs low, so a bigger jar keeps it burning longer. - [11](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/11/) — In a candle it is the wax gas that burns, so a freshly blown-out candle can relight through its smoke; water must never go on burning oil. - [12](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/12/) — Only iron, nickel, cobalt and steel are pulled by a magnet; British pennies and 2p coins made since 1992 are steel with a copper coat, so they stick. - [13](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/13/) — In chalk and limestone areas tap water is hard, and heating it leaves white limescale; limescale is mostly calcium carbonate, like chalk, so it fizzes with acid such as vinegar. - [14](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/14/) — Soap and detergent do the cleaning, not the foam; washing-up liquid must never go in a dishwasher, because its foam would overflow. - [15](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/15/) — Hydrangeas turn blue in acidic soil and stay pink in alkaline soil. - [17](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/17/) — Air is about 78 parts nitrogen, 21 parts oxygen and 1 part other gases in 100; nitrogen hardly reacts, so crisp packets are filled with it. - [18](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/18/) — Helium atoms slip slowly through rubber, so a helium balloon shrinks in a few days; cold air in a tyre shrinks too, so tyre pressure drops on frosty mornings. - [19](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/19/) — The best order for less waste is reduce, then reuse, then recycle; glass and aluminium can be recycled again and again, paper only a few times, and batteries go in special collection boxes. - [20](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/37-olympiad-everyday-chemistry-detectives/20/) — Words from round the world: "dreich" (Scotland) means grey and drizzly, "lekker" (South Africa) means great, "arvo" (Australia) means afternoon, and "y'all" (southern US) means you all. - ← previous: [Olympiad: kitchen chemistry puzzles ★★★](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/36-olympiad-kitchen-chemistry-puzzles/) - ↑ back to [Chemistry](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/)