Activity 2.5 - Comparison of the effectiveness of different household detergents

Students learn something about the effectiveness of household detergents because there are differences in their function, as e.g. only some are antibacterial.

It depends on the facilities and regulations in each country whether the experiments with bacteria can be carried out.

Experimental: see classroom material Activity 2.5

• This activity provides an opportunity to combine biological topics with chemistry, e.g. in terms of enzymes and detergents.
• Have students repeat procedure using chemicals at different concentrations (alkaline, neutral, acidic) instead of cleaners.
• Contact plates should be sealed before incubation with Parafilm® tape or something similar to avoid contamination and exposition.
• The plates should be sealed after incubation.
• After working with bacteria, work areas and hands should be disinfected.
• Check with biology colleagues for disposal of bacteria cultures or do the following:
  • put in autoclave for min. 20 minutes at 121 °C or in pressure cooker for min. 30 minutes at 116 °C or
  • contact hospitals or hygienic institutes to find out whether they will cover the disposal or
  • burn outside and not in vicinity of people/schools...