Mark Rober

Former NASA and Apple engineer who turned engineering projects into some of YouTube's most-watched science content — 50M subscribers watched his squirrel maze, glitter bomb, and dart board car builds. The engineering rigour is genuine (he actually works out the physics and builds functional things) while the entertainment value is mainstream-accessible. His "science of" videos and CrunchLabs educational subscription for kids are the best bridge between serious STEM and broad public engagement.