Sparks and Showers

Theory

Sparks are produced when granules of a substance are thrown out of a combusting composition and continue to burn and glow, whilst falling through the air, producing incandescent light.

Here are some of the substances used to produce incandescent light in the form of flashes, sparks and showers:

Name

Symbol

Characteristics

Aluminium Al Produces white, hot (up to about 3500oC) sparks and is also used to make flashes and loud bangs.
Carbon C Makes a gold coloured spark as it does not reach temperatures as high as that of aluminium (about 1500oC).
Iron Fe Has much the same characteristics as carbon, buts glows for longer once heated, and is not nearly as reactive and so does not burn up as easily before being throws into the air.

Background

This experiment makes a composition which throws out a shower of yellow sparks. It is not really like commercial sparklers but is an interesting effect never the less. Although I have taken nearly all of the experiments from my page, I have left this one in as I have found it in books accompianing chemistry sets, and therefor I know is very safe.

Composition

Name Formula Quantity
potassium permanganate KMnO4 2-3 parts
charcoal C 1 part
iron filings Fe 1 part

You could try substituting the potassium permanganate for any oxidizer, preferably one with a low decomposition temperature. You could also use other metal filings to produce the sparks, for example aluminium filings will produce a white spark. Magnesium, however, is likely to burn too quickly.

There are many different methods for producing sparks and showers. This one is very simply, others are more complex using nozzles, tubes, colours, and so on.

Procedure

  1. Powder the carbon and the potassium permanganate separately
  2. Combine all three powders carefuly by rolling them over one and other on a sheet of paper.
  3. Place the composition in a small, metal container (small means no larger than 2 cm3)
  4. Using a test tube holder, hold the metal container over a bunsen flame until sparks begin to fly out. Once this starts, you can remove the container from the bunsen.

You should wear eye goggles when performing this experiment and use a fume cabinet if available (or just perform outside).

Equation and Explanation

KMnO4 + C + Fe => Fe2O3 + CO2 + Mn + K2CO3

This equation is not balanced or in any way exact as the reaction would vary a lot depending on the exact composition and many other factors.

What is happening is the charcoal is being oxidised by the potassium permanganate, causing a rapid expansion of gas, which is throwing the iron filings out of the metal container, igniting them in the process.