--- title: Thinking like a geographer: rivers, mountains and deserts — a lesson of Mova's school · trees and pragmatics description: «Thinking like a geographer: rivers, mountains and deserts», a lesson of the world course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Rivers flow to the sea because gravity pulls water downhill, and the sea is the lowest place it can reach; the sea --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/) [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/) / Thinking like a geographer: rivers, mo… # Thinking like a geographer: rivers, mountains and deserts Lesson 50 of the world course of Mova's primary school: 13 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/50-why-the-earth-is-so/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/0/) — Rivers flow to the sea because gravity pulls water downhill, and the sea is the lowest place it can reach; the sea does not overflow, because the Sun lifts just as much water from it by evaporation as the rivers bring. - [2](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/2/) — High in the mountains it is colder, even though you are a little closer to the Sun: sunlight warms the ground, the ground warms the air, and air that rises expands in the thinner air above and cools, by about 6 degrees for every kilometre up; so snow lies on Kilimanjaro in Africa, near the equator. - [3](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/3/) — Rain falls when moist air rises and cools; where air cannot rise, rain does not fall, even beside an ocean: along the coasts of Chile and Namibia a cold sea current chills the air from below, the cool air stays low, and the Atacama and Namib deserts lie right next to the water. - [4](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/4/) — Mountains make deserts too: wet wind from the sea climbs the slope, cools and drops its rain on that side, and arrives dry on the far side, which lies in a rain shadow. - [5](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/5/) — Water flows downhill because gravity pulls it down, and the sea is lower than the land around it. - [6](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/6/) — The sea does not overflow because as much water evaporates from it as rivers pour in. - [7](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/7/) — When salt water evaporates, the water leaves and the salt stays behind. - [9](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/9/) — The air is warmed mostly by the ground, which is warmed by sunlight. - [12](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/12/) — Cold sea currents along some coasts cool the air from below and keep it from rising, so little rain falls there. - [13](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/13/) — The Atacama Desert in Chile, beside the Pacific Ocean, is one of the driest places on Earth. - [14](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/14/) — A rain shadow is the dry side of a mountain range, where the wind arrives after dropping its rain. - [15](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/15/) — Water warms up and cools down more slowly than land, so places by the sea have milder winters and cooler summers. - [16](https://md.mova.elamur.ai/free/en/corpora/school/world/50-why-the-earth-is-so/16/) — A desert is a place where very little rain or snow falls, so Antarctica is also a desert. - ← previous: [Map reading puzzles](https://md.mova.elamur.ai/free/en/corpora/school/world/49-map-puzzles/) - next →: [Forces — pushes, pulls, friction and magnets](https://md.mova.elamur.ai/free/en/corpora/school/world/51-forces/) - ↑ back to [World](https://md.mova.elamur.ai/free/en/corpora/school/world/)