Spinning glitter Mystery ////Homemade Science with Bruce Yeany

The spinning glitter mystery or as it was formerly called , the spinning glitter paradox ( it's not really a paradox ) is a simple experiment that I show to my middle school science students, and then ask them to try it for themselves. A simple version can be repeated in flat bottomed glass or plastic containers using one color of glitter or sand. Why does the material settle at different places as the water and bottle is rotated or spin two different ways? I have my own ideas but would like to hear from others in the comments section.

Homemade science is a collection of classroom tested ideas, suggestions, projects, and experiments that I have used in teaching physical science for the Annville-Cleona school district in central Pennsylvania. I am currently in my 38th year of teaching. My intention is to share these ideas with other teachers or anyone who has an interest in science. I have found that designing and building my own equipment has taught me more than any course that I have ever taken. I hope that you consider trying this for yourself.. I also share and show some of these ideas at workshops, science conferences, or inservice presentations.
Videos are shot with a Casio EXH20. Slow motion video clips are either 3.5 or 7 times slower.