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Milk Detergent Experiment

  1. Sep 11, 2004 #1
    For those who haven't seen it, if you put a little soap detergent in a dish of milk with some food coloring in it, you will see the food coloring swirling around and away. Why does this occur?
  2. jcsd
  3. Sep 12, 2004 #2


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    A soap detergent is a surfactant, having both hydrophobic and hydrophilic parts in the framework. A food coloring is possibly a dye such as "Ponceau". The swirling effect is possibly due to solubility of the dye in one part of detergent, with involvements of Brownian motions. I'm not sure about the second though.

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