Completely Optional Knowledge

#CompletelyOptional•completelyoptionalknowledge.org

The podcast where we answer the questions you never knew you had. Produced by Andrew Norton with music by Breakmaster Cylinder.

Last refreshed: August 24th, 2025 at 2:08 AM ⓘ

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Episodes

What Do Tornadoes Smell Like?

New Yorker Alex Kapelman has never seen a tornado, and he’s curious: what do they smell like? With more than 20 years of storm chasing under his belt, extreme weather documentarian Warren Faidley has our answer. And no—he didn’t have to enter the eye of the storm to get it.

Sep 14, 2015•6 min

Why Do Frozen Lakes and Rivers Howl in the Night?

Brigitta Green from the perennial winter wonderland of Minnesota has a fitting question for us about ice. After a mysterious, late night howling sound caused “mass slight curiosity” on the streets of St. Paul last winter, she wants to know how it is that a frozen body of water can produce such an eery noise. Chris Polashenski, Arctic researcher and expert on all things cold, has our answer.

Sep 14, 2015•8 min

What Does the Sun Sound Like?

Space camp alumnus Avery Trufelman from Oakland, California wants to know what the sun sounds like, and so do we! NASA sound and space expert Robert Alexander has our answer, delivered through the wondrous technology of sonification.

Sep 12, 2015•8 min

Can It Really Rain Spiders?

Vancouver meteorologist Kristi Gordon had a not so fortunate on-air experience with an arachnid guest descending on her from above, so she asked us to find out where this “raining spider” came from. Australian naturalist Martyn Robinson explains that this phenomenon isn’t actually as far-fetched as it sounds.

Sep 11, 2015•9 min

Why Do Touch-Me-Not Plants Recoil?

On a recent vacation to Costa Rica, Indianapolis, Indiana nurse Amy Gastelum did what we all would if given the chance: she touched a touch-me-not plant. Now, she wants to know why the plant recoiled at her touch. Evolutionary ecologist Monica Galiano has our answer.

Sep 10, 2015•9 min

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