A new feature on our web site will be a “What’s going on here?” post. Each month we’ll post an interesting question or device, and ask our members to make comments. The first person with the right answer gets bragging rights (or the voice of our web weaver, Lee Trampleasure, on your home answering machine if you’re a fan of “Wait Wait, Don’t Tell Me”).
July 2010: Poly Density Kit
Educational Innovations sells a “Poly Density Kit” shown in the video below:
First the bottle is shaken, and all the beads mix uniformly. After the shaking stops, the blue beads start sinking and the white beads start floating. Within about 15 seconds, all the blue beads are on the bottom and the white beads are on the top. In the next minute or so, the cluster of blue beads slowly rises, and the white beads slowly sink. In the end, all the beads are in the middle, layered by color.
How does this happen? Leave your explanations and questions in the comments section below, (click “Comments” if the section is not visible). if you know how this works, wait and let a few people provide their explanations first.
Future contest ideas?
If you have suggestions for future “What’s going on here?” posts, please mail them to firstname.lastname@example.org.