I wanted to show my son the effect of a surfactant. So I filled two small glasses with tap-water, added a squirt of RinseAid to one and stirred. Then I sprinkled powdered flour on both. My hypothesis was that the powdered flour would sink much more quickly in the water-RinseAid mixture compared to the water because the RinseAid would lower the surface tension. In fact, the experiment was a flop-- I could not see any difference in how fast the flour particles sank in the two glasses. What went wrong?

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    $\begingroup$ How fast the particles would sink depends on viscosity. Surface tension would keep the particles floating. Try floating a sewing needle using a fork to float the needle. Then touch a finger to some dishwashing liquid and touch your finger to the surface of the water. $\endgroup$ – MaxW Oct 27 '17 at 14:26

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