Ever wondered how we go from still air to swirling storm? In this video meteorologist—and storm chaser!—James Spann explains where tornadoes come from.

In truth, we don't know for certain—the exact same conditions won't necessarily give rise to a tornado every time. But we have learned a lot from observations made by scientists over the years. This video really neatly summarizes what happens in just four minutes. And this guy really knows; he's driven into the things. [TED Ed]