where does the light energy of a glowing light wand come from
Glow stick 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).[10] 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.[11] 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 cannot proceed through a regular thermal mechanism.
Firefly The Lampyridae are a family of insects in the beetle order Coleoptera. They are winged beetles, commonly called fireflies or lightning bugs for their conspicuous use of bioluminescence during twilight to attract mates or prey. Fireflies produce a "cold light", with no infrared or ultraviolet frequencies. This chemically produced light from the lower abdomen may be yellow, green, or pale red, with wavelengths from 510 to 670 nanometers.[2] The eastern US is home to the species Phausis reticulata, which emits a steady blue light.