Burning Gel


A burning gel can be produced by mixing aqueous solution of calcium acetate and ethanol.
Two laboratory beakers (one of 100 mL and another 250 mL), two measuring cylinders (one of 50 mL and another of 10 mL), Petry dish, two plastic spoons, hotplate stirrer, stirring bar, matches or better piezo match lighter,  balance,  filter glass rod, 100 mL plastic bottle.

Calcium acetate, ethanol 96 %


Preparation of the aqueous solutions of calcium acetate:
Prepare saturated solution of calcium acetate in 250 mL beaker on the hotplate stirrer by dissolving ~ 40 g of the substance in 100 mL of water. If there is no undissolved substance add more calcium acetate. Collect the prepared solution in a plastic bottle. 
Preparation of the gel:

  • Add 10 mL of the saturated solution of calcium acetate and 50 mL ethanol in 100 mL beaker at the same time.
  • Wait for 10 seconds.
  • Turn the beaker upside down to show that the gel is set.

Fig. 1. Mixing of ethaol and the solution

Fig. 2. No liquid is observed

  • Place some amount of the gel on ceramic plate and place it far from combustible materials (alcohol, wood, paper).
  • Ignite the gel with piezo match lighter.

Fig. 3. Igniting of the gel

Fig. 4. Burning of the gel

Observation and Discussion

Upon mixing of the ethanol and the saturated solution of calcium acetate a white gel is formed. Turning the beaker upside down we can prove that there is no liquid in the beaker. The gel is formed due to the decreased solubility of calcium acetate in the ethanol. This is a case of solvent substitution. The gel is consisted of 3D net in which the molecules of ethanol are captured.
The gel can burn with colorless flame. It is almost invisible so if one wants to show that there is a flame he can use a piece of wood or a piece of paper.  

Safety Tips
Take precautions when working with fire. Keep away combustible materials like ethanol  away from the burning gel.