Slow Motion Video Sheds Light On Why Rain Has That Distinct “Petrichor” Smell
Things the Doctor's Wife didn't teach us.
Say it with me, Doctor Who nerds: petrichor is the smell of dust after rain. But despite having an incredible fancy name that would also double as a wonderful perfume brand, scientists were never quite sure how that whole “rain smell” thing worked, other than a guess that it might be a result of oils and chemicals being released from the ground. Leave it to MIT to set the record straight with a bunch of fancy high-tech cameras, eh?
Dr. Cullen R. Buie and post-doctoral researcher Youngsoo Joung decided to investigate this phenomenon by recording raindrops hitting different types of soil at different speeds of impact. As you can see from the above video, when rain hits a porous surface it causes tiny bubbles to form inside the droplet, which then float to the surface and burst outward in a fizz of aerosols. This, the researchers believe, is what causes the smell to rise up—particularly with light and moderate rain that falls at a slower rate than that of heavy showers.
Surprisingly, Buie and Joung believe that this research, which was recently published in Nature, could have far lasting implications that have nothing to do with that nice smell. “Until now, people didn’t know that aerosols could be generated from raindrops on soil,” Joung said. “This finding should be a good reference for future work, illuminating microbes and chemicals existing inside soil and other natural materials, and how they can be delivered in the environment, and possibly to humans.”
Feel free to point this research out to people who complain about our tax dollars funding weird sounding experiments when it could be used to cure cancer, by the way. Maybe the cure from cancer will come from a natural microbe existing in soil that we haven’t been able to extrapolate out until now or something, and all because a bunch of nerds wanted to know why rain smells. You’re welcome, humanity.
(via the Huffington Post)
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