"This experiment works for a few reasons. Because oil is less dense than water, the water will naturally sink to the bottom of the jar. When the Alka-Seltzer is dropped into the jar, its interaction with the water creates pressure in an upward direction, and the oil pushes it back down. This pressure back and forth is part of what creates the snowstorm. The other element is the interaction between water and sodium bicarbonate in the Alka-Seltzer, which generates carbon dioxide gas. The combination of these factors creates a blizzard every time!"