Love the fresh and earthy smell of rain drops and curious to know where
the smell comes from? Scientists have now identified the exact
mechanism that releases this aroma into the environment.
drops before hitting the ground have no smell but the moment they hit
the ground and interact with dirt, the fresh and almost sweet fragrance
The smell is called "petrichor," that is derived from
the Greek words "petra", meaning "stone", and "ichor", which refers to
the fluid that flows like blood in the veins of the gods.
talked about oils emitted by plants, and certain chemicals from
bacteria, that lead to this smell you get after rain following a long
dry spell," said Cullen Buie, assistant professor of mechanical
engineering at the Massachusetts Institute of Technology in Cambridge.
When a raindrop hits a porous surface it traps tiny pockets of air.
bubbles speed upward before breaking the drop's surface and releasing
microscopic particles, called aerosols, into the air.
Now, researchers think these aerosols carry the rainlike aroma.
The researchers observed the process with a system of high-speed cameras, reported LiveScience.
on the speed of the droplet, and the properties of the soil, a cloud of
hundreds of aerosol droplets might be dispersed in as little as a few
The new research "brings the conversation of
bubble-induced aerosol formation from the ocean over to the land," said
James Bird, assistant professor of mechanical engineering at Boston
"This paper provides an elegant mechanism by which
these microbes can be propelled past the stagnant layer of air around
them to a place where the breeze can take them elsewhere," Bird
The findings were published in Nature Communications.