# Finally: We Know How Many Licks to Get to the Center of a Tootsie Pop

It’s a lot more than three.

It was little more than a brilliant piece of 1970s TV marketing, but Tootsie Pops’ eternal question — how many licks does it take to get to the Tootsie Roll center of a Tootsie Pop? — is one that always demanded an answer, probably because it was easy to test yourself.

There have already been a few scientific studies of just how many licks it would take, using licking machines and human testers, but a new paper in the Journal of Fluid Mechanics has the most detailed analysis yet.

Jinzi Mac Huang, M. Nicholas J. Moore and Leif Ristroph used hard candy in their paper to model how quickly moving fluids can dissolve various surfaces. This kind of destruction is hard to accurately model, however, because some of the dissolved material interacts with the fluid and the surface is constantly changing as it dissolves. Nevertheless, Huang and colleagues were able to produce a mathematical model that could predict the final geometry of a piece of hard candy dissolving in moving fluid.

“As a whimsical application,” the team ends the paper, “this scaling allows us to address the following long-standing question: ‘How many licks does it take to get to the centre of a lollipop?'” Based on their model, it will take about 1,000 licks to get through a centimeter of candy.

A Tootsie Pop has a diameter of over 2.5 centimeters, so the model predicts at least 2,500 licks to get to the center.

The world now totally knows.

1. Eileen says:

Yeah no science lies. It’s roughly 478. As repeatedly tested on MANY movie sets as a bored extra.

2. Sarah says:

I actually did this as my science experiment in grade school when I was little.  LOL  Yeah…. I got a D.

3. Billy B. says:

Shut up Kyle!

4. jeff says:

Actually, the challenge is to get to “the Tootsie Roll center of a Tootsiepop. ” you only need to get through the outer shell, not to the geometric center of the pop. Nice job, science!

• Kyle Hill says:

Yep, I don’t think the researchers factored that part in.

5. Actually it’s around 225. I found that out the old fashioned way.

• Sheldon says:

When I counted as a kid, it was 378.

6. Sorry, but… Thanks to insomnia and boredom one night, I actually tried this out. I subjected myself to about six hours of testing and used three Tootsie Pops. I discovered it takes about 3200 to 3500 licks per pop to get to the center. Additional family members joined in the testing and got similar results, in the 3200-3500 neighborhood.