The science behind the smell of rain |

The science behind the smell of rain

The science behind the smell of rain

Allison Finch
Updated: July 27, 2020 02:20 PM
Created: July 27, 2020 02:17 PM

Before a rainstorm people say that they can smell the rain coming, but do you know that there is actually a scientific explanation behind this? This isn’t some bogus folk story that has been passed down from generation to generation, there are scientific facts that prove you can actually smell the rain.

The “smell of rain” is scientifically known as “petrichor.” This smell, in laymen terms, is the moistening of the ground. The chemical compounds that make up petrichor are known as actinobacteria. Actinobacteria is made up of tiny microorganisms that decompose dead and decaying organic material so that their chemical compounds can help other plants and organisms grow. As a result of this bacteria breaking down organic material, a byproduct called geosmin is formed. Geosmin is what contributes to the petrichor scent.

During the dry days, the actinobacteria isn’t decaying organic material as fast, which means there isn’t a lot of geosmin being formed. When the atmosphere moistens ahead of rain, the ground moistens as well. This allows for the processes to speed up and more geosmin to be formed. When it is actually raining, especially in porous areas (i.e. loose soil) the raindrops hit the ground which allow for the geosmin to be scattered into the air. Thus, making this scent more apparent to the human nose.

The next time it rains outside, be sure to ask your friends or family if they can smell petrichor.

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