(Popular Science) -- At first, the video displays the virtual insides of a crowded passenger airplane. Then all of a sudden, one of the passengers seated in the middle "sneezes." Hundreds of multicolored particles are jettisoned into the air, creating a rainbow-speckled cloud that lingers above everyone’s heads. The cloud dissolves, and the particles disperse, making their way to the unlucky few seated adjacent to the sick passenger.
By the end, the particles have spread all over the cabin, but it's the people seated to the left and to the right of the "sneezer" who are at the highest risk of infection.
This simulation video reveals just one of the many ways influenza particles can travel in a pressurized airplane cabin. Modeling these high-flying infectious scenarios is the job of ANSYS, a company that specializes in precise simulation software. ANSYS uses computational fluid dynamics to simulate the pattern of airflow in airplanes in order to help airlines and health officials trace how flu particles are distributed at 39,000 feet. You can watch a video of their simulation below:
"The particles are colored to show you where the stuff goes," Robert Harwood, aerospace and defense industry director for ANSYS, explains to Popular Science. "Those droplets get picked up by the airflow and get transplanted all over the cabin. They actually spread quite far."