Sure, I’d be happy to summarize the article and provide the answer!
The article from Sciences et Avenir explains how thunderstorms and tornadoes form. Here is a summary of the main points:
* Thunderstorms are caused by the rising of warm, moist air and the sinking of cool, dry air.
* The warm air rises in columns called updrafts, while the cool air sinks in columns called downdrafts.
* Within the thunderstorm, water vapor condenses and forms droplets that become too heavy to be supported by the updraft, so they fall as rain.
* The collision of raindrops with the rising current of air in the updraft creates static electricity, which builds up and eventually discharges as lightning.
* Tornadoes are rotating columns of air that form within thunderstorms.
* They form when the wind changes direction and speed with height, creating a horizontal spinning motion in the lower atmosphere.
* When this horizontal motion is lifted upwards by a strong updraft, it can tighten and intensify, forming a tornado.
The answer to your question is: Thunderstorms form when warm, moist air rises and cool, dry air sinks, causing water vapor to condense and form droplets that fall as rain. Tornadoes form within thunderstorms when a horizontal spinning motion in the lower atmosphere is lifted upwards by a strong updraft and tightens and intensifies, forming a rotating column of air.