Thursday, August 2, 2012

What's That I Smell?

Much to the relief of people around Wisconsin, rain has finally fallen to break this terrible drought! With it has come fresh green grass and flowers, along with something very familiar to us: the smell of rain.

There's something in the air

That smell of fresh fallen rain after an extremely dry couple of days is something so unique, it's hard to not recognize it. In fact, the smell is so unique that it even has it's own name: Petrichor, the smell of rain on dry earth. While we automatically associate this scent with rain, the rain is not what produces it. The smell is actually derived from an oil that is excreted by certain plants during a dry period. This oil is then absorbed by the surrounding soils and rocks. When it rains, this oil is released into the air along with Geosmin, thus producing the well-known aroma.

What is Geosmin?

Geosmin literally means "earth smell" and is an organic compound produced by several different kinds of microorganisms. This scent is very earthy and can be detected by humans in very little concentrations. This compound is what attributes the earthy flavor of beets and the muddy smell of bottom-dwelling freshwater fish (like catfish). Geosmin is most commonly associated with rain and is the main contributor to its smell.

While rain can sometimes put a damper on your outdoor plans, there are still lots of fun things you can do. During a thunderstorm, have your kids count how many seconds it takes for it to thunder after a lightning strike. Every five seconds it takes for the sound to arrive to your ears is how many miles away the heart of the storm is. (Learn more about calculating storm distance here.) After it rains, go on an adventure. Nature can be a completely new place after a good rainfall, so take your kids out on a short hike and have them discuss or record what they see, smell, or hear. Go puddle jumping, rescue earthworms from roadways, or see if you can find any new plants, bugs, or other critters that weren't around before. No matter the weather, there are always things to do in Nature!

1 comment:

  1. One of my favorite days of the year is "Worm Day." That's the day that the worms appear for the first time on sidewalks. This usually happened around April 16, just after a warm rain. The smell is so wonderful and it tells me that spring is here to stay. That first whiff is so refreshing. Perhaps I'll change the name to "Geosmin Day."