Chemistry Demonstration: Molecular Modeling with Candy

Introduction

This is a fun demonstration that teaches students how to build simple molecular models using colored candies. It is relatively simple to prepare and set up, and easy to maintain. The basic principles of building small molecular models of organic compounds can be easily demonstrated. The basics of single, double and triple bonds can be demonstrated.

Materials

• Toothpicks
• Soft, jellied candies of a variety of colors
• A large bowl or ziploc bags to contain the candy atoms
• 3×5 Index Cards
• Markers or Sharpies

Procedure

1. Place all of the jellied candies in a large bowl or ZipLoc bags. You may opt to separate the candies by color, but it is not necessary.
2. Place the toothpicks on the table for easy access.
3. Decide ahead of time a small collection of potential models for participants to construct, and draw their names and chemical structures on the 3×5 index cards. The best molecules to build in this project are small organic molecules (the simpler the better). Planar aromatic compounds also work the best, since they can be built and rested on the table for stability (the candies are often heavy enough to not stay upright in, for example, a tetrahedral carbon atom).Examples of good molecules to use for this demonstration include:
   • Water (H₂O)
   • Acetylene (C₂H₂)
   • Carbon Dioxide (CO₂)
   • Carbonic Acid (H₂CO₃)
   • Ethane
   • Ethanol (CH₃CH₂OH)
   • Ethylene
   • Glucose or Fructose (C₆H₁₂O₆)
   • Methane
   • Propane
   • Ribose
   • 20 Amino Acids
   • Palmitic Acid
   • alpha-Linoleic Acid
   • Cyclohexane (boat and chair conformations?)
4. A single toothpick represents a single bond, two toothpicks represents a double bond, and three toothpicks represent a triple bond.

Safety

This experiment is relatively safe. It uses edible candies. However, because the candies will tend to be handled by many people, eating them is not recommended and should be discouraged. Also, the toothpicks can be sharp, so care should be taken to avoid poking oneself with them.

Disposal of Waste Products

No special requirements. Everything can be discarded through normal disposal procedures.