The evolution of timekeeping - Karen Mensing

View full lesson: http://ed.ted.com/lessons/the-history-of-keeping-timeWhere did time-telling come from? What are time zones and why are there so many of them? Get the answers to these questions and more in this journey through the history of time -- from sundials to hourglasses to modern clocks. Lesson by Karen Mensing, animation by Avi Ofer. Learn more about your ad choices. Visit megaphone.fm/adchoices