High schoolers observe demonstrations that show adhesion, cohesion, equilibrium density, pressure of gases and solubility. In this gases lesson plan, students observe a demonstration of raisins, spaghetti, and popcorn moving up and down in seltzer water. They observe a balloon filled with CO2 from a carbonated beverage squeezed while on top of the bottle and they observe the effects of heat on the solubility of carbon dioxide.