Researchers using high-speed cameras have figured out how rain produces a distinct earthy smell and shown how soil-based pathogens can travel over large areas. Ben Gruber reports.
01:04
02:03
02:59
01:48
01:03
01:47
01:59
01:32
01:13
01:58
02:17
01:47
02:09
02:35
02:13
01:58
01:32
02:08
01:36
02:38