This video was filmed for the paper “Scharfman, B.E., Techet, A.H., Bush, J.W.M. et al. Visualization of sneeze ejecta: steps of fluid fragmentation leading to respiratory droplets. Exp Fluids 57, 24 (2016). https://doi.org/10.1007/s00348-015-2078-4.” The fluid dynamics of a sneeze are important to study in order to properly understand pathogen and disease transmission. The high pressure expels mucosaliva, a combination of mucus and saliva, from the mouth and rather than quickly forming small droplets in an even spread, the proteins present in the mucus increase the viscoelasticity. With this increased elasticity, the mucosaliva tends to cling together and form long, stringy ligaments rather than small droplets. The video was filmed from a side-perspective and lit from beneath and behind with a white background to act as a diffuser. Along with the black and white photography, this provides a clear contrast between the mucosaliva and the background.
Video Credit: B.E. Scharfman, A.H. Techet, J.W.M Bush, and L. Bourouiba
Video found on FYFD: https://fyfluiddynamics.com/2016/02/what-does-a-sneeze-look-like-you-might-imagine-it/?doing_wp_cron=1694116189.9824581146240234375000
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Second Prize
I never really thought about the science behind normal everyday occurrences like sneezing until now and find the fluid dynamics you explained fascinating. The video you provided captures so many of the little details that you wouldn’t normally be able to see and although kind of gross, it’s super interesting to see how the droplets are forming. It’s also cool to see how correct lighting and camerawork can really make a difference when trying to capture fluid phenomena.
Second Prize
I might be a bit biased because this is similar to my research, but I think this imaging of atomization (i.e., droplet formation) and aerosol generation during percussive events is so cool. Lydia Bourouiba does fantastic work. I love that you can see the ligaments that form and their subsequent stretching and breakup. This is a really difficult phenomenon to time correctly and these authors did so wonderfully. I found the lighting to be effective in showing the fluid dynamics and communicating the story — that sneezes generate a lot of droplets.