Apparatus

Trigger pump operated spray bottles such as those used for spraying house plants. Products such as window cleaner are sold in these bottles and empty ones can be cleaned with water and re-used for this experiment. Ideally, one bottle is needed for each metal, although it is possible to wash one out between solutions.

Chemicals

The quantities given are for one demonstration.

About 10 cm of ethanol for each metal.

Less than 1g of a salt of each metal. Chlorides are best, but other salts are worth trying if chlorides are not available. Examples of compounds that work well are: sodium chloride, potassium chloride, lithium iodide and copper sulphate.

Before The Demonstration

Make a saturated solution of each salt in about 10cm of ethanol. Only a few mg of each is required. Place each solution in a spray bottle and label it.

The Demonstration

Adjust the nozzles of the spray bottles to give a fine mist and spray the solutions into a roaring bunsen flame. Take care to spray away from yourself and the audience. The colour of the resulting jet depends on the metal used. The solutions can be retained for future use and can be stored in the plastic bottles for several weeks, at least, without apparent deterioration of the bottles.

Students can observe line spectra through hand held spectroscopes.