Around the Corner is a great 1930s video that clearly describes how the differential gear works and why we need them in our cars. Bonus: motorcycles ride in formation to victorious band music. Watch more smart videos about gears and cars on this site. h/t Kottke. This Webby award-winning video collection exists to help teachers, librarians, and families spark kid wonder and curiosity. TKSST features smarter, more meaningful content than what's usually served up by YouTube's algorithms, and amplifies the creators who make that content. Curated, kid-friendly, independently-published. Support this mission by becoming a sustaining member today.