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Our first experiment sought to determine whether or not alum was the sole factor in the formation of surface foam. After dosing the water with varying alum concentrations, it was determined through photographs and observation that no foam was formed. Sample photos are included in Figure 1 below. 
Although the foam was not formed, this data was crucial to our research. Not only did it minimize the list of potential foam formation factors, it also help build our understanding of foam formation. As a result of foam not forming due to alum addition at the surface of the water, we also were able to rule out alum addition under the water surface as intuitively it was a solution to the form formation.
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In our next experiment, we varied the concentration of NOM but included an aerator to provide bubble directly into what would be the (flocculation?) tank. At concentrations below 2 g/mL we found that no foam was formed. However at higher concentrations of Humic Acid, we found that large bubbles would rise and then quickly pop in the center of the tank. In the meantime, smaller bubbles would form around the edges of the tank and were slightly more persistent as seen in Figure 2 below.
Bubbles form when water molecules form bonds around air pockets. A surfactant is generally an organic molecule that has both hydrophobic and hydrophilic. Due to this polarity, surfactants form micelles in water which helps to stabilize air bubbles and prevent them from aggregating. Humic acid is a weak surfactant, so though it did reduce the aggregation of air bubbles it still occurred. This resulted in large, non persistent air bubbles that formed a foam at the surface of the water.
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