It is made up of a saturated salt solution in the bottom, mineral oil on top of that, and finally isopropanol. Layer it the same way, starting with the isopropanol which I colored bright blue, then the oil, and finally the saturated salt solution that I colored really red. I put a stopper on it and the kids enjoyed shaking it. Unfortunately if it mixes too much the food coloring becomes less vivid. Heat indigo solution.
Dip yarn in.
As it pulls out, it will change color. See Cyndi for complete prep. Use temperature gloves and forceps. Freeze any organic material and break. In a 100 mL or large graduated cylinder, pour half full of carbonated water or other clear carbonated beverage.