Screaming jelly babies
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Screaming jelly babies is a classic chemistry demonstration which is practiced in schools all over the United Kingdom. It is often used at open evenings to demonstrate just how much fun secondary school science can be. The following text gives an explanation of how to perform the experiment. This should only be done by an experienced chemist or chemistry teacher.
This demonstration nicely shows just how much energy there is in a "jelly baby". Potassium chlorate is a very strong oxidizing agent that oxidizes the sugar in the jelly baby all at once.
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Safety
- Make sure test tube is squeaky clean. Any trace of an oxidizable material can cause an explosion
- Surround the apparatus with safety screens
- Ensure the pupils / audience are seated several metres away and that they are wearing eye protection
You will need
- Jelly babies
- Large test tubes
- Clamp Stand {retort stand}
- Potassium chlorate
- Tongs
- Access to a fume cupboard
- Bunsen burner
- Safety goggles
- Fire resistant surface
Method
- Put 10mg potassium chlorate in large test tube.
- Clamp the tube in a clamp stand at approx. 60 ° (just off the vertical) then melt the powder in a fume cupboard with a bunsen burner. Wear a full face visor.
- Turn the bunsen off, then, using tongs and wearing heat resistant gloves, drop in the jelly baby.
Results
If all goes well the jelly baby will burst into flames and make a very nice screaming sound as it burns to death! A smell of candy floss will also steal its way around the room.
Links
Virtual School videos page (http://vs.eun.org/ww/en/pub/virtual_school/depts/chemistry/resources/listdocument/digitalvideo.htm) Page with a link to a zipped video of a Screaming Jelly Babies experiment.