Pharaoh's snake from calcium gluconate

When a solid substance is heated it forms gray foam.

Scientific name: Calcium gluconate decomposes under heating.


Decomposition of calcium gluconate

ФАРАОНОВА ЗМЕЯ из глюконата кальция - опыты

Calcium gluconate + fire (4x faster)

by Alexandr Savochkin


Wear eye protection goggles.There is a serious fire risk - a fire extinguisher should be ready.

Always follow general safety recommendations. Please note that conducting chemistry experiments you must comply with the relevant legal procedures in your country.

Reaction formula

2C12H22CaO14 + O2 → 22H2O + 21C + 2CaO + 3CO2

Step-by-step instruction

  1. Prepare a tablet of dry fuel and calcium gluconate tablets.
  2. Ignite the dry fuel.
  3. Use tweezers to put a few calcium gluconate tablets on burning dry fuel.
  4. When calcium gluconate is exposed to heat it forms low density carbonaceous foam.

Scientific background

When calcium carbonate monohydrate is heated it demonstrates a huge volume expansion. It looks like a grey foam snake and is caused by vaporization of loosely bound water and dehydration of hydroxyl groups of the compound. When calcium gluconate is purolysed at temperature of dry fuel the reaction looks as follows:

2C12H22CaO14 + O2 → 22H2O + 21C + 2CaO + 3CO2

The snake is gray-colored because of the presence of calcium oxide and carbon mixture.


Published on 18 March 2015

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst