Time is the fourth dimension of spacetime

This video about space-time, relativity and time travel was submitted to the Flame Challenge 2013, whose goal was to give an answer to the question "What Is Time?" that an 11-year old could understand. Tens of thousands of grade 5 students from all over the world rated the submitted entries, and my video made the short list of finalists: http://www.centerforcommunicatingscience.org/the-flame-challenge-2/2013-flame-challenge-finalists/

Видео Time is the fourth dimension of spacetime канала ThisIsPhysics / Voici la physique - Marc Séguin