Snot Clouds Achieve Unexpected Buoyancy




This is Scientific American 60-Second Health. I'm Cynthia Graber. Got a minute?
"When you have to sneeze or cough, do it into the bend of your arm."
"Sneeze into your arm with Elmo. Ah-choo!"
Gordon and Elmo from Sesame Street are right.
And MIT researchers recently found that viruses can travel much further than we thought.
Which shows how important it is to block coughs and sneezes.
The researchers used high-speed imaging of folks coughing and sneezing, along with simulations and mathematical models.
The new research shows that multiple drops travel in a cloud.
And the cloud's turbulence pulls in surrounding air, which allows the goopy assemblage to maintain buoyancy and move farther.
Heavier particles drop out first, but about five times further out than had been previously predicted.
And the small ones swirl around and can be carried 200 times past previously predicted distances.
The research is in the Journal of Fluid Mechanics.
Longer flight distances means coughs and sneezes can often reach ventilation systems.
The researchers thus encourage hospital and airplane engineers to consider designs that block droplet flight and thus keep everyone else from catching your cold.
Thanks for the minute, for Scientific American 60-Second Health. I'm Cynthia Graber.