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Asked by anon-250983 on 31 Mar 2020.
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Eóghan Forde answered on 31 Mar 2020:
Hello Toby, (Thanks for getting in touch)
Although it is not an area I have studied since leaving school I will give it a go.
When the sun warms the Earth’s surface, the atmosphere warms too. This results in parts of the Earth receiving direct sun rays all year (making them warm places). Other places receive indirect rays, so their climate is colder (like the North and South poles as well as Scotland!). As a result warm air, which weighs less than cold air, rises. This cool air then moves in and replaces the rising warm air. This movement of air is what makes the wind blow.
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Katie Sparks answered on 1 Apr 2020:
Everything in wants to move from hot to cold. This is because hot has more energy and cold means that the energy is more evened out over everything.
The way that the Earth tries to even out the temperature is through the wind.
This is done through the warm air raising, cold air filling in the gaps that Eoghan has told you about below. -
Martin Coath answered on 1 Apr 2020:
This is *such* an interesting question, and would require a *very* long answer (even if I was fully qualified to write it – which I am not).
Certainly wind can be caused in the way described by Eóghan in a previous answer – the movement of air from cold to hot areas.
Also the movement of air from regioins of high pressure to regions of low pressure. This is what happens when you blow on your hands – you use your lungs to create a high pressure inside your mouth and the air moves to a region of low pressure in the room.(But this just forces us to ask why we *have* areas of high and low pressure all over the earths surface.)
These two things, temperature difference and pressure difference, cover most types of wind. But have a look at this video which is really interesting:
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Philip Denniff answered on 1 Apr 2020:
Your question could be answered in two areas of science, in geography the movement of air through the atmosphere and biologically the generation of gas by the digestive system of animals. Eoghan has covered the former up to my schooling standard but I will add that wind is also the movement of air along a pressure, from areas of high pressure to areas of low pressure. Movement of things along a gradient from high to low crops up again and again is lots of branches of sciences. As for the latter my school boy biology cannot come up with an answer.
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Simon Waldman answered on 1 Apr 2020: last edited 1 Apr 2020 9:32 am
The other answers give a good explanation of the big picture, but I’ll try to explain it another way:
Hotter and colder parts of the atmosphere develop for lots of reasons. Air, like many things, expands as it warms up. This means that warm air has a lower density than cold air – i.e. a box full of warm air would weigh less than a same size box full of cold air.
If you think about the column of air that’s resting on a bit of ground – from the ground up to the top of the atmosphere – then the weight of the air is what produces atmospheric pressure. So where the air is warmer, and the air weighs less, there’s a lower pressure than where the air is cooler.
Gases will tend to flow from high pressure to low pressure. That makes sense, because the extra pressure is “pushing” them. And a flow of air is wind. So that’s how winds start.
The rotation of the earth produces “Coriolis” forces, which cause straight flows to curve. Coriolis forces are a complicated topic, so if you want to know about them you should ask another question – but that’s why winds don’t usually flow in straight lines, and why you see the curves and spirals on weather maps.
The wind is also affected a lot by the shape of the land, especially in mountain areas: Hills and mountains can block or funnel the wind.
Similar mechanisms happen at lots of scales – from the planet-wide scales shown in the video that somebody else linked, to local winds in coastal areas, which are produced because the land heats up and cools down faster than the sea when the sun rises and sets.
Stepping back a long way from all of this gives us an interesting thing to think about: Because wind is caused by differences in temperature, and because nearly all heat on Earth comes from the sun, the wind is ultimately caused by the sun. And hence wind power could be thought of as a type of solar power!
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Kaitlin Wade answered on 2 Apr 2020:
Again, resorting to these awesome scientists explaining complex air movements!
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Michael Schubert answered on 2 Apr 2020:
Everyone has given you lots of good information about wind – but here are a few fun activities to try out if you want to learn more!
You could make a weather vane: http://stem-works.com/external/activity/161
You could even make your own hovercraft: https://monkeysee.com/wind-power-science-project-hovercraft/ -
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