demonstrations:flaming_gummy_bear

Flaming Gummy Bear

Materials: ★★★ Requires materials not commonly found in school laboratories
Difficulty: ★★★ Requires a more experienced teacher
Safety: ★★★ Only to be attempted with adequate safety procedures and trained staff

Categories: Combustion, Oxidation and Reduction, Thermochemistry

Alternative titles: Screaming Gummy Bear

Summary

A gummy bear (or sugar sweet) is dropped into molten potassium chlorate, which decomposes to release oxygen. The sugar rapidly combusts, producing heat, light, gas, and a dramatic flame.

Procedure

  1. Set up a ring stand and clamp a borosilicate test tube so the open end points away from people and toward the fume hood interior.
  2. Add about 5–7 g of potassium chlorate to the test tube.
  3. Place a Bunsen burner beneath the test tube and heat until the solid fully melts to a clear liquid.
  4. Using tongs, quickly drop a single gummy bear (or sugar sweet) into the molten oxidizer, then step back behind the shield.
  5. Allow the reaction to run to completion before turning off the burner and letting the tube cool undisturbed.
  6. After cooling, follow local hazardous waste procedures to dispose of residues.

Flaming Gummy Bear - sciencefix:


The Sacrificial Gummy Bear - Potassium Chlorate for the Win - Jon Bergmann:


📄 Exploding Gummy Bears - CSUB: https://www.csub.edu/chemistry/_files/Exploding_Gummy_Bears.pdf

Variations

  • Test different candies (e.g., marshmallows, hard candies) of similar mass to compare vigor and duration of the reaction.

Safety Precautions

  • Teacher demonstration only; do not scale up the quantities.
  • Safety glasses and face shield required; flame-resistant lab coat and heat-resistant gloves recommended.
  • Perform in a functioning fume hood or or outside with a clear blast shield.
  • Keep all observers behind the demonstrator and at a safe distance; point the test tube opening away from people.
  • Be aware of bright, flashing light; individuals sensitive to light should not view directly.
  • Potassium chlorate is a strong oxidizer; keep away from organic materials and avoid contamination. Do not premix sugar with chlorate or grind them together.
  • Use only clean borosilicate glassware; inspect for cracks before heating.
  • Have appropriate fire suppression available; never cap the test tube.
  • Allow complete cooling before handling residues. Waste can be washed down the sick.

Questions to Consider

  • Is the reaction endothermic or exothermic? (Exothermic)
  • What provides the oxygen that enables rapid combustion? (Decomposition of potassium chlorate to release oxygen gas)
  • Which species is oxidized and which is reduced? (Sugar is oxidized to carbon dioxide and water; chlorate is reduced to chloride)
  • Why is a purple or lilac flame sometimes observed? (Emission from excited potassium atoms/ions)
  • Why must the test tube be pointed away from the audience? (To prevent hot gases or ejecta from being directed toward people)
  • How would smaller candy pieces change the reaction rate? (Greater surface area increases the rate and intensity of the reaction)
  • Write a balanced overall equation for sucrose reacting with potassium chlorate. (C12H22O11 + 8 KClO3 → 12 CO2 + 11 H2O + 8 KCl)