failed simple experiment with surfactant

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?


