The Science of Sticky

Stickiness is serious business. Scientists study it, throwing around words like "viscoelasticity" and examining the super-sticky feet of little lizards called geckos. So explaining the stickiness of candy is complicated.

But let's start by explaining why sugar is sticky. Sugar molecules are made up of carbon, oxygen, and hydrogen atoms. Together, they create tiny sugar crystals, and bunches of crystals all together are what you find in your sugar bowl.

Sugar + Water = Sticky

If you add water (moisture), the sugar crystals dissolve, breaking the chemical bonds between the sugar molecules. Then the sugar sticks to whatever it touches.

Would it surprise you to know that sugar is an ingredient in some glues? Probably not, if you've every held a piece of candy in your hand or put it in your pocket.

A Word About Your Teeth...

Dentists (and parents) often tell you not to eat too much sticky stuff. For someone with braces, sticky candy is a problem because it can get stuck in all those wires and brackets. Even if you don't have braces, sticky candy can stick to your teeth and lead to cavities. If you do eat candy, be sure to brush your teeth afterward.

In this experiment, you'll play around with candy to see which is the stickiest. These factors will affect the stickiness: warmth, moisture (water), and how much oil the candy contains.

What you need:

• Several blocks of chewy candy such as taffy, Starburst, Laffy Taffy, or Airheads
• Small hard candies such as Valentine conversation hearts, Smarties, or Sweet Tarts

What to do:

1. Wet and mold each chewy candy until it is soft and easy to work with.
2. Try to attach round candy wheels to make a candy car.
3. The candy that best holds the wheels is the stickiest.

© Loralee Leavitt. Used with permission.
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Reviewed by: Mary L. Gavin, MD
Date reviewed: January 2011