How Everything Works
How Everything Works How Everything Works

Question 760

What are the two chemical in glow sticks? — JW, Westport, CT
I believe that the glow sticks contain luminol and hydrogen peroxide, which mix when you crack the glass ampoule and begin to emit light. There are several other chemicals present in the sticks to assist and control the process, but the principal reaction is one in which the hydrogen peroxide oxidizes ("burns") the luminol molecule. The result is a product molecule that is initially in an excited state—its electrons have more energy than they need—and it emits a particle of bluish-violet light. Since our eyes aren't particularly sensitive to that bluish-violet light, it's often converted into more visible light with the help of a fluorescent dye. The green light sticks probably contain sodium fluorescein molecules, each of which can absorb a photon of bluish-violet light and reemit some of its energy as a photon of green light. Other dyes, probably rhodamines, are used to make red or orange light sticks.

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