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Emulsions Experiment 52.

To determine some of the factors that affect the formation and stability of emulsions.

Mayonnaise:

Egg yolk Vinegar Oil Salt

1 tablespoon

1/2 cup

1/2 teaspoon

18 grams

15 grams

108 grams

In studying emulsions, a microscope is a great aid. For very fine emulsions a small portion is placed on a slide and covered with a cover glass. With coarse and unstable emulsions it is better not to use a cover glass for the weight of the cover glass often breaks the emulsion. If the oil or fat is colored a dark red with Scarlet R, the type of emulsion formed can be determined with the microscope. An oil-in-water emulsion has a red oil dispersed in small spheres; a water-in-oil emulsion has a red field and light-colored spheres. To color the oil or fat, add the powdered Scarlet R and then stir. It should stand over night to dissolve the dye thoroughly.

Store the emulsions in jelly glasses. Label, then cover the glasses to prevent evaporation. Put away in the refrigerator to determine the permanency of the emulsion.