Fountain candles are small tubes filled with chemicals that when ignited spew out a plume of glowing sparks into the air. They sure capture attention! The effect can last a few seconds (cake fountain candles), up to a minute (bottle fountain sparklers) or several minutes (special effects for stage shows and concerts). These devices all consist of some combustible materials packed into a cardboard tube with the length of the visual effect being determined by the amount and specific composition of the chemicals packed into the tube.
Fountain candles are not inherently safe or dangerous, but they can be used in a safe or dangerous manner. Unfortunately, the tragic fire on New Year鈥檚 Day 2026 in a Swiss nightclub that killed 40 people and injured 116 others is an example of a dangerous, irresponsible use of 鈥渂ottle sparklers.鈥� The sparklers were clipped onto the necks of champagne bottles, ignited, and paraded among the celebrants. It is believed that the pyrotechnic effect was sustained long enough to ignite the soundproofing insulation in the ceiling, that lacking any fire retardant quickly burst into flames.
The exact chemical composition of the fountain candles that caused the tragedy, or indeed that of any other fountain candles, is not known since there is no requirement for manufacturers to reveal exact formulations. However, it is possible to make a reasonable guess at composition from published patents for various fireworks and common stick type sparklers. In my case, having presented numerous chemical 鈥渕agic shows,鈥� I can add some personal experience for producing such pyrotechnic effects.
All fireworks rely on a combustion process that has three basic requirements: some sort of fuel to burn, a supply of oxygen, and a source of energy to initiate the reaction between the fuel and the oxygen.聽The oxidizer in the common wire type of sparklers is usually potassium chlorate, potassium perchlorate or potassium nitrate. Powdered charcoal serves as fuel, and a metallic powder produces sparks when ignited by the burning fuel. The components are held together with a binder such as dextrin, a type of sugar, that also acts as a fuel. These chemicals are blended into a slurry, and the sparklers are made by dipping a wire into the mix, slowly withdrawing it and allowing the mix to solidify.
Fountain candles are variants of the traditional sparklers. Instead of being coated onto a wire, the chemicals are packed into a tube. The metallic powder can be iron or titanium, with the latter more likely since it produces very bright sparks that cool down quickly. Potassium perchlorate or potassium nitrate are the likely oxidizers, and dextrin serves as fuel and binder. I suspect there is also some nitrocellulose in the mix to boost performance. That suspicion is based on my experience of producing a 鈥渕agic spectacle鈥� by igniting a mix of nitrocellulose, a bit of black gunpowder, and powdered aluminum in an Erlenmeyer flask. A shower of sparks impressively bursts out through the narrow neck of the flask! The effect is very similar to that produced by a fountain candle although it doesn鈥檛 last as long.
Black powder is the oldest chemical explosive, with its discovery dating back to 9th century China. It is made by combining the oxidizer saltpeter (potassium nitrate) with sulfur and charcoal, both of which serve as fuel. When a pile of black powder is ignited, it noiselessly burns and produces smoke which actually consists of tiny suspended particles of carbon. However, if the powder is confined in a container, upon ignition it produces gases at high temperature that quickly expand and push against the surroundings. The earliest firearms consisted of a metal tube packed with black powder and fitted with a metal ball. Ignition of the powder caused the expanding hot gases to expel the ball out of the tube accompanied by a bang as the emerging gases propel air molecules towards eardrums. In my demo, combustion of the black powder helps to force the glowing aluminum particles out of the flask.
Nitrocellulose in the mix makes for a more sustained combustion. It is the main component of 鈥渟mokeless gunpowder鈥� and is produced by treating cellulose with a mixture of nitric and sulfuric acids. This results in nitro groups (NO2) becoming attached to the cellulose where they serve as a source of oxygen upon ignition. Nitrocellulose can then be seen as cellulose with a built-in oxidizer. It burns very quickly with an orange flame, producing carbon dioxide and water vapour that blast out of the container. If powdered metal has been added, it is ignited by the burning nitrocellulose and the glowing particles are ejected. In my version, to ignite the mix I use a fuse which is just a wire coated with gunpowder. In fountain candles, it is a string that is lit. In all probability, this is made by coating with wax a length of cotton yarn wound around a core of compressed black powder. The string burns down and meets some easily combustible fuel such as powdered sulfur or antimony sulfide at the top of the candle that catches fire and ignites the mix below. Presto a shower of sparks shoots out.
The chemistry involved in fountain candles is fascinating, but the Swiss tragedy is just one example, albeit a horrific one, of thousands of pyrotechnic accidents reported every year. They are mostly burns, lacerations and eye injuries but there are also fatalities. It is best to remember the proverb, 鈥渋f you play with fire, you can get burned.鈥�
