How many bathtubs-full of coffee do U.S. physicists (or mathematicians) consume daily?)

How many active volcanoes are there in the world? (Thanks to Shaila Patricia Ramirez Vientós, Puerto Rico for asking this during my ODU REYES lecture.)

Look for the answers online at under “Browse,” at the very end of the current issue.

Question suggestions are always welcome!

For more Fermi questions and answers, see Guesstimation 2.0: Solving Today’s Problems on the Back of a Napkin, by Lawrence Weinstein (Princeton University Press, 2012).

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