5: Foam Fire Extiguisher

This is a fun method for producing a foam fire extinguisher. It can be messy!

What you will need

2 x 50cm3 beakers
50cm3 measuring cylinder
100cm3 conical flask
bung with delivery tube drawn out into a fine nozzle
spatulas
stirring rods
dropping pipette
aluminium sulphate powder
sodium hydrogencarbonate
washing up liquid or liquid detergent
eye protection
protective clothing (e.g. lab coats)

What you do

  1. Eye Protection
    Put 2 spatula measures of aluminium sulphate into a beaker containing 30cm3 of water. Stir vigorously.
  2. Now add 2 spatula measures of sodium hydrogencarbonate to the other beaker and add 30cm3 of water to this. Stir vigorously.
  3. Pour the aluminium sulphate solution into the conical flask and add a few drops of washing up liquid. This is the foaming agent.
  4. Warning
    Carefully add the contents of the other beaker to the conical flask. Put the bung and delivery tube on quickly and stand back! Make sure you direct the jet into a sink.
  5. Try again and then record any changes you make.
Eye Protection
eye protection must be worn

Warning
slippery floors

Contents