The COVID-19 outbreak has led to two admonitions.  First, wash your hands.  Second, wash your hands for at least 20 seconds. Two Twitter threads on handwashing came up recently.  One deals with the chemistry of handwashing.  The other contains suggestions for 20 second song clips you can use if you’re tired of singing Happy Birthday twice.

First, the chemistry.

While that’s interesting, it’s not especially entertaining.  In the pdf below, clicking any of the images will open a browser window that plays the clip.