Trivia

Hard

What Is Responsible For That Distinct Post-Rainfall Smell?

Geosmin
Methanol
Decomposing Leaves
Ozone
A person walking through a rainy and misty forest with an umbrella.
Kaitha Poo Manam/Wikimedia

Answer: Geosmin

When a dry spell is broken by rainfall, there is a distinct smell in the air after the storm. That smell, a rich earthy smell that strongly resembles the scent of fresh beets plucked from the soil, is called petrichor—a term coined by researchers in the 1960s to describe the post-rainfall scent released by freshly dampened dry earth.

The petrichor itself is caused by a very specific organic compound: geosmin. Geosmin is produced by many classes of microbes, including cyanobacteria and actinobacteria, and released into the soil when these microorganisms die. During rainfall, the geosmin is released into the air along with a natural “additive” (an oil that is exuded by certain plants during dry periods and absorbed by clay-based soils and rocks).

Geosmin is also found in beets and in bottom-dwelling fish like carp and catfish (and is responsible for the earthy/”muddy” flavor of bottom-dwelling fresh water fish). Humans are particularly sensitive to the compound and can smell it in concentrations as low as five parts per trillion.

Trivia

Hard

The First Woman To Appear On U.S. Currency Was?

Trivia

Easy

What Movie Series Were The First Themed LEGO Building Sets Based Off Of?

Trivia

Hard

The Lowest Number Zip Code In The United States Belongs To?

Trivia

Very Hard

The Original “007” Was A Real Spy By The Name Of?

Trivia

Very Hard

The First “Wake Up Call” Played To Astronauts Was?

Trivia

Hard

Now A Sci-Fi Staple, The Term “Earthling” Originally Referred To?

Trivia

Hard

The Primary Mineral Responsible For The Petrification Of Petrified Wood Is?

Trivia

Hard

The Original Aerosol Can Was Invented To Apply What?

Trivia

Easy

What Is It Illegal For The U.S. Treasury To Print On Currency?

Trivia

Hard

Which Candy Was Originally Produced Using Decommissioned World War II Machinery?