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Wind is caused by the movement of air. When you use a fan, you make wind! In the natural world, wind can take on many different forms, from a pleasant breeze to a devastating hurricane.
So, how are these movements of air formed?
A mass of air moves due to the temperature: it rises when it’s hot. Once at the top, it cools down, becomes heavier and starts to drop. When a mass of air moves, another one takes its place. This movement is… wind! The rotation of the Earth influences the direction of air movement. Then there are obstacles in the landscape, such as forests or valleys to consider. Mountains also modify the trajectory and speed of air masses. Deviation, slowing down or speeding up… It’s not easy to follow the wind in the mountains! Landmasses heat up and cool down quickly, but in water, temperature variations are slower. This difference in speed leads to a contrast of temperatures between air masses. This is how breezes, gales or even cyclones develop. In certain cultures, the origin of the wind is associated with a god or spirit: Aeolus in ancient Greece, Fūjin in Japan, Kukulcan the Mayan god. To find the direction of the wind, just look at a weathercock!
Nom de l'auteur : Jacques Azam
Producteur : Milan Presse, France Télévisions
Année de copyright : 2018