Video: What Is a Year and How Is It Measured?
How did measuring a year came about and why does February 29 only come once every four years? Minute Phsyics knows the answers and they have it all in their latest video.
The video is an explanation of a year and how long it takes for one physical body to orbit another. Educational. Even for an adult like me! Hit past the jump to watch the video.
[YouTube via Laughing Squid]