| Procedure |
| Weigh washing powders | |
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Weigh 1 g of each biological washing powders into boiling tubes A, B & C respectively and 1 g of non-biological washing powder in boiling tube D. Add 100 ml distilled water to each tube. |
| Add photographic film | |
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Add strips of photographic film about 4 mm wide into the above boiling tubes which contain the washing powder solution. |
| 45℃ water bath | |
 |
Incubate the boiling tubes in a 45℃ water bath overnight. |
| Record and Compare | |
Record and compare the degree of clarity of photographic films between biological and non-biological washing powders. |
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HKIEd. All Rights Reserved.
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