Topic: Rain.
Why does rain smell?
Maybe it applies a special perfume.
No.
Rain is just water and water doesn't have any smell.
So, what's that smell?
The distinctive smell which frequently accompanies the first rain after a dry weather.
Is scientifically called petrichor.
It basically comes from plants and bacteria called actinomycetes which live in the soil.
Now during a long dry spell, the plants release oils into the soil to block other seeds from germinating.
Thus reducing competition for water.
Whereas, the actinomycetes produce a chemical called geosmin.
Now when rain hits the ground, it brings up the oils and geosmin which then mix with air.
The combination of this geosmin along with the plant oils form the smell which we receive after the rain.