That is what my daughter called this science experiment anyway. We poured cooking oil into plastic bottles, about 1/2 way. Then we colored some water and poured that into the oil. That was pretty exciting itself, watching the oil move through the water. Then we plopped an Alka-Seltzer tablet into the bottle and watched the bubbles! Super exciting!! The oil is lighter than water so it rises to the top, then the Alka-Seltzer produces carbon dioxide bubbles. The bubbles carry the colored water to the tope of the bottle, then pop and the water sinks back down. The darker the color of water the easier it is to see. Just watching the bubbles is fun too. We used several tablets to keep the fizz going.
When we were done, I poured the water/oil mixture into smaller bottles so the kids could watch the oil and water not mixing.
The pictures don't show the process so well, hence the detail.