There are plenty of features in modern cars that seem impressive until you think about how they actually work. But rain-sensing windshield wipers still have a little bit of magic to them. You can be driving along on a dry road, a few drops hit the windshield, and suddenly the car starts wiping the glass without you touching anything.
It gets even stranger when the rain starts coming down harder. Instead of simply switching the wipers on, the system can increase their speed as the windshield gets wetter. There's no person sitting behind the scenes making that decision—the car is detecting what's happening on the glass and responding to it automatically.
