Want to get your Halloween sugar fix, but you don't want to get bogged down in doom and gloom? Use your Skittles (or some food coloring and sugar) to make yourself a rainbow in a glass, and then drink it down.
First, you need five glasses. Fill four with equal amounts of water (two to three tablespoons). The fifth will remain empty until the end of the demonstration.
Now, those of you using Skittles will separate out the Skittles into flavors and put different amounts of each flavor into each glass. It might get complicated because you will have to dissolve the Skittles without altering the amount of water. Microwaving generally does the trick. When you've nuked the water for long enough that the skittles dissolve, add enough water so that each glass has the same amount of liquid.
If you don't want to be bothered with that, add different color drops of food coloring to each glass, and then mix in one tablespoon of sugar into the first glass, two into the second, three into the third, and four into the fourth.
Each of the glasses of sugar water will have different densities. The one most thick with sugar will be densest, so pour that first into your empty glass. Then, carefully, over the back of a spoon, pour the next-dense liquid onto the first. Repeat this careful pouring process until all of the liquids are layered on top of each other.
Most experiments do this with things like oil, water, alcohol, and cream, because they are easier to keep separate. As you can see during this experiment, though, just different densities of sugar water is enough. Eventually, through the random jiggling of molecules, and unlike oil and water, the different sugars won't separate themselves out again if mixed, so you have to pour and drink carefully. Still, this is an easily drinkable rainbow — if you have a fondness for sugar.
Top Image: Laurent Deschodt. Second Image: JMU. Via Candy Experiments and About.