--- title: Clever reasoning about water and matter — a lesson of Mova's school · trees and pragmatics description: «Clever reasoning about water and matter», a lesson of the world course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Because ice floats, a pond freezes from the top down. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/) [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/) / [World](https://md.mova.elamur.ai/free/en/corpora/school/world/) / Clever reasoning about water and matter # Clever reasoning about water and matter Lesson 20 of the world course of Mova's primary school: 14 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/world/20-reasoning-water-and-matter/). - [1](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/1/) — Because ice floats, a pond freezes from the top down. - [2](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/2/) — The ice lid insulates the water below, which stays liquid, so fish and frogs can survive the winter at the bottom. - [3](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/3/) — A cold glass gets wet on the outside because water vapour in the warm air touches the cold glass, cools and condenses: the water comes from the air, not through the glass. - [4](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/4/) — Salt is spread on icy roads because salty water freezes at a lower temperature than pure water; the salt dissolves in the thin wet layer on the ice and makes it melt even a few degrees below 0 °C. - [5](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/5/) — Good reasoning asks: where does the water or the heat come from, where does it go, and what would happen if things were different? - [6](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/6/) — Water expands by about one tenth when it freezes. - [7](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/7/) — Ice is less dense than liquid water, so it floats. - [8](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/8/) — Water is densest at about 4 °C, so in winter the deepest water of a lake is often about 4 °C while the top freezes. - [9](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/9/) — Ice and snow are good insulators and slow down the cooling of whatever is under them. - [10](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/10/) — Salty water freezes at a lower temperature than fresh water. - [11](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/11/) — In very hard frost road salt stops working, because even salty water freezes when it is cold enough. - [12](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/12/) — The drops on the outside of a cold glass come from water vapour in the air. - [13](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/13/) — In very dry air a cold glass gets far fewer drops on it than in damp air. - [14](https://md.mova.elamur.ai/free/en/corpora/school/world/20-reasoning-water-and-matter/14/) — Melting ice takes in heat from around it, which is how ice cools a drink. - ← previous: [Mixtures and how to separate them](https://md.mova.elamur.ai/free/en/corpora/school/world/19-mixtures-and-separating/) - next →: [Parts of a plant and what each does](https://md.mova.elamur.ai/free/en/corpora/school/world/21-parts-of-a-plant/) - ↑ back to [World](https://md.mova.elamur.ai/free/en/corpora/school/world/)