Question: where does the light energy of a glowing light wand come from

title: Glow stick
text: The glow stick contains two chemicals and a suitable dye ( sensitizer , or fluorophor ) . This creates an exothermic reaction . The chemicals inside the plastic tube are a mixture of the dye and diphenyl oxalate . The chemical in the glass vial is hydrogen peroxide . By mixing the peroxide with the phenyl oxalate ester , a chemical reaction takes place , yielding two moles of phenol and one mole of peroxyacid ester ( 1 , 2 - dioxetanedione ) . The peroxyacid decomposes spontaneously to carbon dioxide , releasing energy that excites the dye , which then relaxes by releasing a photon . The wavelength of the photon -- the color of the emitted light -- depends on the structure of the dye . The reaction releases energy mostly as light , with very little heat . The reason for this is that the reverse 2 + 2 photocycloaddition of 1 , 2 - dioxetanedione is a forbidden transition ( it violates Woodward -- Hoffmann rules ) and can not proceed through a regular thermal mechanism . Oxidation 

Answer: answer: The glow stick contains two chemicals and a suitable dye. The chemicals inside the plastic tube are a mixture of the dye and diphenyl oxalate and a vial of hydrogen peroxide. By mixing them the reaction releases energy mostly as light and with very little heat.