Hank explores the science behind the first kiss -- and all the kisses that come after it -- and also sets you straight about the vernal equinox, what it is, and why this year's is special!

A Chinese folk legend may have given rise to the idea that you can only balance a raw egg on its end during the vernal or autumnal equinox. Actually you can balance one on any day of the year. Here's how.

This video provides an explanation of the solstices and equinoxes, which are important astronomical events that mark the changing seasons.<b<br/>r/>

This video is part of the 8-part series, Earth’s Rotation and Revolution.