A planet money podcast from a few years ago on the kilogram: 
<a href="http:&#x2F;&#x2F;www.npr.org&#x2F;templates&#x2F;story&#x2F;story.php?storyId=112003322" rel="nofollow">http:&#x2F;&#x2F;www.npr.org&#x2F;templates&#x2F;story&#x2F;story.php?storyId=1120033...</a>