"How many licks does it take to get to the Tootsie Roll center of a Tootsie Pop?"

Today, October 31st, is Halloween, a day that children celebrate by dressing up in costumes and going door-to-door in search of candy, usually asking the question, "Trick or Treat?"  They almost always get a "treat" so there is rarely, if ever, a "trick"!  If I do happen to write a blog post on October 31st, I usually try to make it at least a little fun - for some of my past Halloween posts, see "Don't go anywhere with scary, spooky, or haunted in the title" or "Are Trick-or-Treaters honest?"  I'll keep with the tradition today.  

There's a really good chance that most children who go Trick-or-Treating tonight will find a Tootsie Pop in their bag at the end of the night.  Tootsie Pops were basically lollipops that had a Tootsie Roll at the center.  There was a famous commercial from my childhood, "How many licks does it take to get to the Tootsie Roll center of a Tootsie Pop?"  A boy goes asking around to see if the smartest animals (Mr. Fox, Mr. Turtle, and finally Mr. Owl) know how many licks it takes to get to the center of the Tootsie Pop.   All I can say is that "If there's anything I can't stand, it's a smart owl" (just watch the commercial). 

Raise your hand if you ever tried to find out as a child!  I never made it - just like Mr. Turtle (and as it turns out, Mr. Owl), I always gave up after so many licks and just bit down into the candy to get to the Tootsie Pop.  Well, apparently several independent groups of scientists have actually tried to find out the answer.  It's a legitimate scientific question!

A group of Purdue University engineering students (Boiler Up!) designed and built a licking machine modeled after the human tongue and determined that it took an average (over a number of trials) of 364 licks to get to the Tootsie Roll center of a Tootsie Pop.  As a comparison, a group of twenty human volunteers also performed the test (without the machine) and found that it took only 252 licks.  Not to be outdone by their Big Ten rivals (at least in academics, though certainly not in football - but if they weren't stealing signs, who knows?), a chemical engineering student at the University of Michigan created his own customized licking machine and found that it took 411 licks to get to the center.  

There was a larger clinical study involving 130 human subjects from Bellarmine University.  They actually published their findings (check out their study results here), and it seems that there can be variation in the number of licks required based on the color of the Tootsie Pop!  Regardless, on average, they found that it took 175 licks in just over 14 minutes to get to the Tootsie Roll center. (oh, and Orange Tootsie Pops are the quickest).  Finally, a group of middle school science students at Swarthmore Junior High School found that it took an average of 144 licks.

Wow - based on the best available scientific data, it can take anywhere from 144 licks to 411 licks to get to the center.  It's clear to me that the world may never know how many licks it really does take to get to the Tootsie Roll center of a Tootsie Pop.  Trick or Treat!