What does a mask do?

What does a mask do?

Blocks respiratory droplets coming from your mouth and throat.

Two simple demos: First, I sneezed, sang, talked & coughed toward an agar culture plate with or without a mask. Bacteria colonies show where droplets landed. A mask blocks virtually all of them.

What about keeping your distance?

Second demo: I set open bacteria culture plates 2, 4 and 6 feet away and coughed (hard) for ~15s. I repeated this without a mask. As seen by number of bacteria colonies, droplets mostly landed <6 ft, but a mask blocked nearly all of them.

I’m aware that this simple (n=1) demo isn’t how you culture viruses or model spread of SARS-CoV-2. But colonies of normal bacteria from my mouth/throat show the spread of large respiratory droplets, like the kind we think mostly spread #COVID19, and how a mask can block them!

My mask vs. no mask demonstrations got perfectly summarized in this brief 34 second video. Masks keep your respiratory secretions to yourself!
@providence_phc

Something extra cool, local reporter Kevin Kim came to our teaching lab and tried this same demonstration himself (his reaction in this clip was absolutely genuine). Story airs tonight
@KHQLocalNews
The take home: masks matter!

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