Wind and weather Lesson 15 of the physics course of Mova's primary school: 18 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 Wind is simply air on the move, and air moves from places where it presses harder to places where it presses less, like a crowd spilling out of a full room into an empty one. 1 On a sunny afternoon at the beach the sand warms faster than the sea, the warm air above it rises, and cooler air from the sea rushes in to take its place: that is the sea breeze on your face. 2 Moving air pushes on whatever is in its way, so it can lift a kite, flip an umbrella, slam a door or, when it is very fast, push a tree over. 3 The wings of a plane turn the air downwards, and the air pushes back up on the wings strongly enough to hold up a giant jet. 4 Weather forecasters watch the air pressure: high pressure usually means calm, settled days, low pressure means clouds, wind and rain. 5 Wind is air moving from where it presses harder to where it presses less. 6 On a sunny day the land warms faster than the sea, so warm air rises over the land and cooler sea air blows in; at night the land also cools faster than the sea, so the breeze often turns round and blows out to sea. 7 High pressure usually brings calm, settled weather, and low pressure usually brings clouds, wind and rain. 8 A barometer measures air pressure, and a falling barometer warns that bad weather may be coming. 9 The push of the wind grows very quickly with its speed: wind twice as fast pushes about four times as hard. 10 A kite flies because the wind is turned downwards by the tilted kite and pushes it up, while the string holds it at an angle. 11 A windsock shows which way the wind blows, and pilots take off into the wind because it gives the wings more air flowing over them. 12 An umbrella turns inside out when a gust pushes up underneath it harder than from above. 13 A plane's wings turn air downwards and make the air over the top flow faster with lower pressure, so the air pushes the wings up; the faster the plane goes, the more lift (upward push) its wings make, so it races along the runway first. 14 A tornado is a column of air spinning very fast with very low pressure in its middle, and its winds can rip off roofs and lift cars. 15 In a tornado people shelter in a cellar or a small room in the middle of the house, away from windows. 16 Wind through an open window can push a door shut with a slam, which is why a door stop keeps fingers safe. 17 Blowing out a candle pushes the flame's hot gas away from the wick, while very gentle blowing can bring more air and make it brighter. ← previous The air presses on everythingnext → Pressure tricks: pumps, tyres and vacuums↑ back to Physics This page in Markdown → https://md.mova.elamur.ai/free/en/corpora/school/physics/15-wind-and-weather/