I bought a huge bag of skittles for Bria's My Little Pony Party, and most of them did not get eaten-- not sure how. So I decided to try a couple density experiments with them including a Density Rainbow and Floating S's.
I started with 7 glasses (6 for the Density Rainbow and 1 for the Floating S's). I sorted out my skittles for the Density Rainbow and set them in front of the appropriate glass: 2 red, 4 orange, 6 yellow, 8 green, and 10 purple).
Then I added 2 tablespoons of heated water to each of the 5 glasses and added the skittles that were next to the glass.
And waited. And stirred.
And waited. And re-heated.
And finally after about 40 minutes they were dissolved! Time to make a rainbow. I started by pouring the purple into the empty cup. Then very carefully using a syringe I added the green. I had to place the tip of the syringe against the glass as I pushed the plunger slowly to prevent the liquids from mixing.
Then we tried to add the yellow by slowly pouring it over the back of a spoon held against the glass. That didn't work too well for us. So now we had a weird colored layer with some purple still at the bottom, so we went back to the syringe for the orange and red.
It didn't turn out perfectly since our yellow and green mixed a bit with the purple, but we had some layers at least. Since it is just sugar water the colors did end up mixing together the longer it sat, but for a while you could see how more sugar made a denser water that would stay at the bottom while less sugar made a less dense water that would float on the top similar to oil.
Our Floating S's experiment was started at the same time as the Density Rainbow, but it wasn't as involved. I filled the last glass about 2/3 full with the warm water and had Nadia throw in some random skittles. Then we just let them set while we worked on the other experiment.