Green fluorescent droplets moving against a black background. These droplets are the contents of a glow stick, with sodium hydroxide (NaOH) solution added to the mixture. Glow sticks contain two chemicals and a fluorescent dye. The chemicals, diphenyl oxalate and hydrogen peroxide, react and release light, a process known as chemiluminescence. The dye absorbs this light energy and re-emits it as a specific wavelength. Different dyes have different emission wavelengths, allowing many different colours to be obtained. See clip K004/4993 for a pink dye. This footage has been sped up ten times.