140 years ago today, Dmitri Mendeleev presented his new Periodic Table of the Elements to the Russian Chemical Society.

 

 Standard Podcast [3:01m]: Play Now | Play in Popup | Download

113 years ago today, Henri Becquerel discovered Radioactivity

 

 Standard Podcast [2:01m]: Play Now | Play in Popup | Download

56 years ago today, DNA was discovered

 

 Standard Podcast [1:51m]: Play Now | Play in Popup | Download