Screaming jelly babies
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"Screaming Jelly Babies" (British English), also known as "Growling Gummy Bears" (American and Canadian English), is a classroom chemistry demonstration in which a piece of candy bursts loudly into flame when dropped into potassium chlorate.<ref>Template:Cite web</ref> The experiment is practiced in schools around the world and is often used at open evenings to show the more engaging and entertaining aspects of science in secondary education settings.<ref>Template:Cite web</ref><ref>Template:Cite news</ref>
The experiment shows the amount of energy there is in a piece of candy. Jelly babies<ref>Template:Cite web</ref> or gummy bears<ref name=UMass>Template:Cite web</ref> are often used for theatrics. Potassium chlorate, a strong oxidising agent, rapidly oxidises the sugar in the candy causing it to burst into flames. The reaction produces a "screaming" sound as rapidly expanding gases are emitted from the test tube.<ref>Template:Cite web</ref> The aroma of caramel is given off.<ref name="Royal Society of Chemistry-2023">Template:Cite web</ref> Other carbohydrate or hydrocarbon containing substances can be dropped into test tubes of molten chlorate to produce similar results.<ref>Template:Cite web</ref><ref>Template:Cite web</ref>
Net reaction
[edit]4 KClO3 (s) + C12H22O11 (s) + 6 O2 (g) → 4 KCl + 12 CO2 (g) + 11 H2O (g)
Net Reaction of Oxidation of Sucrose and Potassium Chlorate
Mechanism
[edit]The solid potassium chlorate is melted into a liquid.
KClO3 (s) + energy → K+ClO3− (l)
The liquid potassium chlorate decomposes into potassium perchlorate and potassium chloride.
4 KClO3 → KCl + 3 KClO4
The potassium perchlorate decomposes into potassium chloride and oxygen.
KClO4 → KCl + 2 O2
The sugar in the candy reacts with oxygen, forming water and carbon dioxide. The reaction is exothermic and produces heat, smoke, and fire.
C12H22O11 (s) + 12 O2 (g) → 12 CO2 (g) + 11 H2O (g) + energy.<ref>Template:Cite web</ref>
Safety measures
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Care should be taken in performing this experiment, which should only be attempted by a professional. Potassium chlorate is a strong oxidizer and can cause fire or explosions. It is toxic by inhalation or ingestion and is hazardous to aquatic environments.<ref>Template:Cite web</ref> Reagent grade potassium chlorate should be used. Upon completion of the demonstration, all chemicals should be disposed of in designated chemical waste containers to prevent harm to people or the environment.<ref name="Royal Society of Chemistry-2023" />
All participants in the experiment should wear personal protective equipment, including eye protection, and should stand a safe distance away from the demonstration.<ref name="Education in Chemistry-2021" /> A face-shield and heat resistant gloves should be worn by the person adding the jelly baby to the molten potassium chlorate.<ref name="Education in Chemistry-2021">Template:Cite web</ref>
Variations
[edit]Deviation from the experiment is not recommended, and has been linked with accidents.<ref name="Education in Chemistry-2021" /> Candy with low moisture content or high surface area may cause explosions.<ref name="Education in Chemistry-2021" />