This document provides instructions for an experiment where students observe a "fire snake" formed from the incomplete combustion of sugar. The experiment involves mixing sugar and baking soda, placing the mixture on ethanol-soaked sand, and lighting it to form a burning snake-like structure of carbon. It explains that the baking soda releases carbon dioxide, limiting the oxygen available and causing some of the sugar to decompose into solid carbon rather than fully combusting to carbon dioxide and water.

1. A Fire Snake
2020-1-LT01-KA229-078054 "Reading through the lens of STEAM"
In this activity students observe a snake formed from fire.
They will explore how incomplete combustion of glucose yields carbon.
Materials
Some Sand
Baking soda 1 tablespoon
Sugar 4 tablespoons
Small ceramic plate or bowl
Small cup
Measuring spoons
Some Ethanol
Long lighter or matches

2. A Fire Snake
2020-1-LT01-KA229-078054 "Reading through the lens of STEAM"
Preparatory Work
This experiment requires dry sand. Your sand might be damp if you get it
from somewhere that is in contact with the ground, like a sandbox. If
needed, spread your sand out on a baking tray and place it in direct
sunlight or in the oven until it is completely dry.
Only do this experiment with adult supervision, in a location where it is
safe to have a small fire. Have a fire extinguisher accessible for
emergencies.
1.
2.

3. A Fire Snake
2020-1-LT01-KA229-078054 "Reading through the lens of STEAM"
Procedure
Fill your plate or bowl with sand.
1.
2. Soak the sand in lighter fluidsome ethanol.
3. Mix 1 tbsp baking soda with 4 tbsp sugar.
4. Pour the sugar/baking soda mixture into a pile on top of the sand
5. Use matches or a lighter to ignite the ethanol.
6. Watch , and be patient. The reaction may be slow to start.
What happens? Keep watching until it stops growing!
.

4. A Fire Snake
2020-1-LT01-KA229-078054 "Reading through the lens of STEAM"
Sugar (C6H12O6) can be oxidized, which means that it can react with
oxygen to form other products.
When you expose sugar to an open flame, it will burn quickly and react with the
oxygen in the air. This is called a combustion reaction.
C6H12O6 →6CO2 + 6H2O
A different reaction happens if there is not enough oxygen present during the
combustion to form CO2. In this case, the sugar decomposes, resulting in
elemental black carbon (C), or charcoal.
The baking soda (sodium bicarbonate, NaHCO3) decomposes at high temperatures
and releases lots of CO2.
2 NaHCO3 → Na2CO3 + H2O + CO2
This means that there is not enough oxygen for all the sugar to be converted into
CO2 and water via a combustion reaction. Instead, some of the sugar decomposes
into elemental carbon and starts forming the solid black snake-like structure.