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Abstract
Some laundry detergents have added enzymes that break down proteins, helping to remove them from the cloth fibers, and thus remove stains. You can perform a scientific test of these enzymes' stain-fighting ability. Do background research on the enzyme(s) in the detergent, and on the substances you choose for making the stains. Try to predict for which substances the enzymes will be effective. Cut a piece of light-colored cotton cloth into identical 10-cm squares. Choose different types of stains you'd like to test (e.g., mustard, grass, egg yolk). For each substance, prepare identical stains on three pieces of cloth: one for washing with regular detergent, one for washing with enzyme-containing detergent and one that is not washed, for comparison. Circle the stained area with permanent marker. Also label the squares to indicate which treatment the fabric received (stain and washing). Prepare detergent solutions and wash the squares in the same way (e.g., by shaking them in a closed jar for a specified amount of time). Rinse, dry and compare the results. Here are some additional ideas you might try. Many proteins are denatured when heated to 60°C or more. Do you get the same results if you heat the detergent solutions before using them (hint: use a double-boiler on your stove to do this). How do the pH values of the two detergents compare? (VanCleave, 1993, 25–29)Bibliography
VanCleave, J., 1993. A+ Projects in Chemistry: Winning Experiments for Science Fairs and Extra Credit. New York, NY: John Wiley and Sons.Variations
Last edit date: 2006-12-27 18:06:09
If you like this project, you might want to think about career opportunities in
Chemistry.
Everything in the environment, whether naturally occurring or of human design, is composed of chemicals. Chemists search for and use new knowledge about chemicals to develop new processes or products. Learn more about this career: Chemist.
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