MIT scientists use high-speed film to explain the smell left behind by rain

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BOSTON–You know that dewy smell that comes during a rainstorm?

Well, scientists at MIT used high-speed cameras to capture the effect of how the rain leaves behind a specific aroma–which Australian scientists named petrichor– on film in slow motion.

When a raindrop falls it supposedly traps small air bubbles where it hits the surface. According to the researchers, the small bubbles–known as aerosoles, which are minute particles that absorb sunlight and create haze, as well as deepen the colors of sunrises and sunsets–may have scents associated with them in natural environments. The combination of those scents and the ones produced by bacteria and viruses in the soil create that familiar smell.

The smell is then spread by the wind, which also can help explain how diseases like E. coli are spread via the environment, according to the video.

Check out the video MIT released that shows the phenomenon in slow motion.