The document explains how lava lamps work using the science of density. It describes how oil is less dense than water, so the oil floats on top of the water inside the lava lamp. When Alka-Seltzer tablets are added, they cause the oil to bubble and rise, creating the lava lamp effect. The procedure for making a simple lava lamp at home with water, oil, food coloring, and Alka-Seltzer tablets is then outlined.