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Investigating the effectiveness of biological washing powders containing enzymes on removing protein stains.
Method
Method to test enzyme effectiveness in washing powders
1. Cut identical pieces of white cotton fabric stained with egg (protein stain). 2. Prepare three washing solutions: one with biological washing powder, one with non-biological washing powder, and one with water only. 3. Soak each stained fabric piece in the respective solution at 30°C for 30 minutes. 4. Rinse and dry the fabric pieces. 5. Compare the stain removal visually or using a colorimeter.
| Step | Description |
|---|---|
| 1 | Prepare identical stained fabric pieces |
| 2 | Prepare washing solutions |
| 3 | Soak fabric pieces at 30°C for 30 minutes |
| 4 | Rinse and dry fabric |
| 5 | Compare stain removal |
- a[1]
Identify the independent variable in this investigation.
Aim for approximately 1 distinct marking point.
- b[2]
Describe how you would ensure the investigation is fair and reliable.
Aim for approximately 2 distinct marking points.
0 of 2 parts answered
Answer every part before opening the mark scheme.
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