--- title: Browning apples, rotting and mould — a lesson of Mova's school · trees and pragmatics description: «Browning apples, rotting and mould», a lesson of the chemistry course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Cut an apple for your lunchbox and by break time the white flesh has gone brown. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/) [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/) / Browning apples, rotting and mould # Browning apples, rotting and mould Lesson 23 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/23-browning-apples-rotting-and-mould/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/0/) — Cut an apple for your lunchbox and by break time the white flesh has gone brown. - [1](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/1/) — Cutting opened the apple's cells, so air reached their chemicals, and an enzyme helped them react with oxygen. - [2](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/2/) — A squeeze of lemon slows it, because the acid stops the enzyme working well. - [3](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/3/) — Food goes off in two main ways: its own chemistry changes, like a banana ripening and browning, and tiny living things move in: bacteria and fluffy mould growing from spores in the air. - [4](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/4/) — Germs need water and warmth. - [5](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/5/) — So people keep food by taking those away: the fridge slows them, drying makes raisins, lots of sugar makes jam, and salt kept fish and ham for months long before fridges existed. - [6](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/6/) — Rotting is not only bad news. - [8](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/8/) — A cut apple goes brown because air reaches its chemicals and an enzyme helps them react with oxygen; lemon juice slows this because its acid stops the enzyme working well. - [9](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/9/) — Cut avocado browns by the same enzyme-and-oxygen reaction; covering it tightly helps, while leaving the stone in only protects the part it touches. - [10](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/10/) — As a banana ripens, starch turns into sugar and the skin browns; ripening is controlled by a gas called ethylene that fruit gives off, so fruit in a bowl ripens together, and hard fruit shut in a bag with a ripe banana ripens faster. - [11](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/11/) — Mould grows from tiny spores in the air and likes damp, warm, sugary food. - [12](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/12/) — Mould sends threads deep into soft food, so cutting off the visible spot does not make soft food like strawberries safe. - [13](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/13/) — Cold slows down bacteria, mould and chemical reactions, so food lasts longer in the fridge. - [14](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/14/) — A freezer stops germs growing almost completely but does not kill most of them, so defrosted meat must still be cooked properly. - [15](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/15/) — Drying removes the water germs need, so dried fruit keeps for months; ancient Egyptians dried food in the sun to store it. - [16](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/16/) — Lots of sugar pulls water out of germs and stops them growing, so jam keeps for months; low-sugar jam and opened jam still go mouldy. - [17](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/17/) — A "best before" date is about quality and a "use by" date is about safety; dry food after its best-before date is often fine, which helps stop waste. - [18](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/18/) — A compost heap gets warm because microbes break down the scraps and release energy as heat. - [19](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/23-browning-apples-rotting-and-mould/19/) — Salt pulls water out of food so germs cannot grow; sailors and others salted meat and fish before fridges existed. - ← previous: [Milk, cheese and yoghurt](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/22-milk-cheese-and-yoghurt/) - next →: [Soap and why washing works](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/24-soap-and-why-washing-works/) - ↑ back to [Chemistry](https://md.mova.elamur.ai/free/en/corpora/school/chemistry/)