Glaciers and ice ages Lesson 54 of the geography 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 .
0 A glacier is a river of ice. 1 Snow piles up year after year, gets squashed into ice, and the ice becomes so heavy that it slowly flows downhill, often only a few metres a day. 2 As it moves it scrapes the land like giant sandpaper with rocks frozen into its base. 3 It turns a narrow V-shaped river valley into a wide U-shaped valley with a flat floor and steep sides; when the sea floods one, we get a fjord, like the ones in Norway. 4 For the last 2.6 million years Earth has swung between cold glacial periods and warmer interglacials. 5 About 20,000 years ago ice covered much of Britain, so much water was locked up that the sea was about 120 metres lower and you could walk to Europe across Doggerland. 6 Imagine a boulder as big as a car sitting alone in a field, made of rock found nowhere nearby: ice carried it there. 7 Today almost all mountain glaciers are shrinking fast because of human-caused warming, and hundreds of millions of people depend on rivers they feed. 8 A glacier is a huge mass of ice that slowly flows downhill under its own weight. 9 Today two great ice sheets cover Greenland and Antarctica and hold about 99% of the world's glacier ice. 10 Glaciers carve wide valleys with flat floors and steep sides, called U-shaped valleys. 12 During the last 2.6 million years the Earth has swung between cold glacial periods and warm interglacials. 13 About 20,000 years ago ice sheets covered much of Britain, Scandinavia and northern North America. 14 In the ice age, sea level was about 120 metres lower, so Britain was joined to Europe by a land called Doggerland. 15 Glaciers dropped huge boulders, called erratics, far from the rocks they came from. 16 From about 1300 to 1850 Europe had a cooler period called the Little Ice Age, with glaciers advancing in the Alps and the Thames in London sometimes freezing hard enough for fairs on the ice. 17 The Little Ice Age was much milder than a real ice age, and scientists still discuss its exact dates and causes. 18 Today almost all mountain glaciers are shrinking fast because of human-caused global warming. 19 Mountain glaciers feed rivers that hundreds of millions of people depend on, especially in Asia. ← previous Rivers shaping the landnext → Coasts and caves↑ back to Geography This page in Markdown → https://md.mova.elamur.ai/free/en/corpora/school/geography/54-glaciers-and-ice-ages/