How to Make “Black Snakes” or “Glow Worms”
Black snakes, sometimes called glow worms, are small tablets that you light, using a punk or a lighter, that burn to produce long black ‘snakes’ of ash. They produce some smoke (which had a characteristic, probably toxic odor), but no fire or explosion. The original fireworks used to contain salts of a heavy metal (such as mercury), so while they were marketed for kids to play with, they really weren’t that much safer than conventional fireworks, just dangerous in a different way. However, there is a safe way to make black snakes. You can heat baking soda (sodium bicarbonate) with sugar (sucrose) to produce carbon dioxide gas that puffs up black carbon ash (see a video).
WHAT YOU NEED:
- alcohol or fuel oil (such as Heet lighter fluid)
- baking soda
- powdered sugar (must be powdered!)
WHAT TO DO:
- Mix 4 parts powdered sugar with 1 part baking soda. For example, you can use 4 tsp sugar and 1 tsp baking soda.
- Make a mound with the sand. Push a depression into the middle of the sand.
- Pour the alcohol or other fuel into the sand to wet it.
- Pour the sugar and soda mixture into the depression.
- Ignite the mound, using a lighter or match.
WHAT HAPPENS: At first, you’ll get a flame and some small scattered blackened balls. Once the reaction gets going, the carbon dioxide will puff up the carbonate into the continuously extruded ‘snake’. Actually, you don’t even need the sand. You can use baking soda and sugar in a metal mixing bowl, add the fuel, and light the mixture. It works fine. The old firework snakes had a distinct smell. These have a smell too, a bit like burnt marshmallows! If you use pure ethanol, sugar, and baking soda, then there is nothing toxic about this project. CAUTION: DO NOT add fuel to the burning snake, since you risk igniting the alcohol stream!
HOW IT WORKS:
The sugar and baking soda snake proceeds according to the following chemical reactions, where sodium bicarbonate breaks down into sodium carbonate, water vapor, and carbon dioxide gas while burning the sugar in oxygen produces water vapor and carbon dioxide gas. The snake is carbonate with black carbon particles:
2 NaHCO3 → Na2CO3 + H2O + CO2
C2H5OH + 3 O2 → 2 CO2 + 3 H2O
These instructions were adapted from a tutorial given on Boing Boing which in turn came from a defunct Russian site. The Russian site suggested two additional ways to make chemical snakes:
Ammonium Nitrate Black Snakes:
This works the same way as the sugar and baking soda snake, except you use ammonium nitrate (niter) instead of sugar. Mix one part ammonium nitrate and one part baking soda. This recipe is more like what you would see in commercial black snake fireworks, which are supposedly composed of soda with nitrated naphthalenes and linseed oil. It’s another very safe demonstration, though not safe enough to eat, like sugar and baking soda.
Ammonium Dichromate Green Snakes:
The green soda snakes are made from:
- two parts of ammonium nitrate
- one part of powdered sugar
- one part of ammonium dichromate
Mix the ingredients, add a small amount of water, and roll WITH GLOVES into a snake. Allow the snake to dry. It is easier to use a hair dryer to speed up the process. Light one end of the snake. In this case, an orange snake burns to green ash. It’s worth knowing how to do this demonstration if you have ammonium dichromate and ammonium nitrate on hand, otherwise let the Russian photos suffice and play with the sugar and baking soda snakes instead. Another (spectacular) form of black carbon snake results from reacting sugar and sulfuric acid. Visit my future post on the sugar and sulfuric acid black snake. I will post this experiment with complete instructions and write how it works.