Why are manhole covers round? - Marc Chamberland

View full lesson: http://ed.ted.com/lessons/why-are-manhole-covers-round-marc-chamberland Uploaded 13-04-15 Why are most manhole covers round? Sure it makes them easy to roll, and slide into place in any alignment. But there’s another, more compelling reason, involving a peculiar geometric property of circles and other shapes. Marc Chamberland explains curves of constant width and Barbier’s theorem. Lesson by Marc Chamberland, animation by Pew36 Animation Studios. Learn more about your ad choices. Visit megaphone.fm/adchoices Learn more about your ad choices. Visit megaphone.fm/adchoices