The chemiluminescence of luminol (cold light) is a popular demonstration. This reaction can be displayed even more dramatically by using a fountain apparatus to mix the liquids. This is part of the Education in Chemistry Exhibition Chemistry series: chemistry demonstrations to capture your students' imaginations: http://rsc.li/EiCExChem 22/3/13 - This video has been featured on Reddit and turned into an animated gif! http://www.reddit.com/r/chemicalreactiongifs/comments/1apgvg/glowing_luminol_fountain/