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
- 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.
- Add about 5–7 g of potassium chlorate to the test tube.
- Place a Bunsen burner beneath the test tube and heat until the solid fully melts to a clear liquid.
- Using tongs, quickly drop a single gummy bear (or sugar sweet) into the molten oxidizer, then step back behind the shield.
- Allow the reaction to run to completion before turning off the burner and letting the tube cool undisturbed.
- After cooling, follow local hazardous waste procedures to dispose of residues.
Links
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)