Stories about the sometimes obvious but sometimes sneaky effects of the way that we humans rearrange the elemental stuff around us. First you'll hear the late, great, Oliver Sacks talk about how the Table of Elements inspired his lifelong quest for knowledge. Then, you'll hear Reporter Avir Mitra and science journalist Lydia Denworth bring us a story about how one man’s relentless pursuit of a deep truth about the Earth led to an obsession that changed the very air we breathe.