Mark Rober

A former NASA engineer (seven years at JPL working on the Curiosity rover) and Apple product designer who turned engineering projects into some of YouTube's most-watched science content — nearly 82 million subscribers have watched his squirrel maze series, glitter bomb videos, and other elaborate 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 among the best bridges between serious STEM and broad public engagement.