Purity
As a physics graduate, married to a chemistry graduate...
![Purity from xkcd.](https://www.quantumtea.com/content/images/wp/2008-06-xkcd-purity.png)
(NB: in his about section, the author says "You can post xkcd in your blog (whether ad-supported or not) with no need to get my permission")
As a physics graduate, married to a chemistry graduate...
(NB: in his about section, the author says "You can post xkcd in your blog (whether ad-supported or not) with no need to get my permission")