Page 211 - Big Ideas Year 10 sciPAD 2025

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SCIPAD - BIG IDEAS - BOOK 2
LIFE OF MICROBES
The Effectiveness of Soap
Aim: To investigate the effect of washing your hands with soap.
Equipment: Agar plate Marker pen (vivid, etc.) Adhesive tape Soap
Method: 1. Turn your agar plate upside down and divide the petri dish into thirds by drawing
lines with the indelible marker and label as shown in the diagram below.
2. Remove the lid of your petri dish and carefully press a few fingers gently onto the
surface of the nutrient agar in the section labelled “unwashed”. Replace the lid.
3. Wash your hands with water. Shake them dry (do not use a towel). Remove the lid,
and press the same fingers onto the nutrient agar in the section labelled “water”.
Replace the lid.
4. Wash you hands using soap and water for at least 30 seconds. Shake them dry.
Remove the lid, and press the same fingers into the nutrient agar in the section
labelled “soap”. Replace the lid.
5. Seal the plate with adhesive tape. Name it and place in the incubator upside down.
Leave for at least 24 hours.
Results: Sketch your results on the agar plate below.
SOAP WATER
UNWASHED
Conclusion: 






1. Suggest another investigation that would also explore the effectiveness of soap.



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