"How many licks does it take to get to the Tootsie Roll center of a Tootsie Pop?" was the question posed by a young boy to an owl in a popular series of commercials from the 1970's. In the ad, Mister Owl takes three licks of the lollipop, before biting into the sweet treat, and declaring happily, "three!"
New York University (NYU) researchers analyzed the same question, and determined the answer was much closer to 1,000. Study revealed that the candy wears down at the rate of around four-tenths of an inch per 1,000 licks. The popular treat measures 1.063 inches in diameter, and research revealed that the lollipop wore away near the base first, flattening out, while the top remained rounder as the candy was being consumed.
The study examined the effects of running water on several hard candies, using time-lapse photography. This new research not only answers a question long quoted as a rhetorical question, but could also assist fields of study, including examination of how rocks and other materials wear away under the influence of running water. This question is currently studied by geologists, as well as chemical engineers and medical researchers.
Researchers found the action of the liquid produced similar shapes, regardless of the initial shape of the candy. The side facing the flow of water became rounded and smooth, while the opposite end became pitted with divots and bumps.
"We call this shape a 'sculpture' - dissolved by the flow - and its shape gave us the clues to how dissolution works and how to model it mathematically," Leif Ristroph, assistant professor of mathematics at the Courant Institute of Mathematical Sciences, operated by NYU, said.
This model was then utilized to determine how many licks it would take to reach the center of a Tootsie roll lollipop.
When managers at Tootsie Roll heard about the experiment, they sent several boxes of the treats to NYU investigators.
Investigators in the study manufactured some of their own lollipops for the research, but many of the products produced were never placed into the experiment, and were instead eaten by researchers. Although some of the candy-eating was done in the name of "research," investigators usually wound up crunching through the lollipop.
"Our model assumes no biting!" Ristroph joked to the press.
The original television commercial to feature the famous question, first aired in 1970, is available on the manufacturer's Web site.
The answer to the 45-year-old lollipop-related question was detailed in the Journal of Fluid Mechanics.
