How Do Toys Glow in the Dark?

How Do Toys Glow in the Dark?

Remember when glow in the dark toys were all the rage as a kid? There were bouncy balls and plastic bugs and those little green stars that everybody stuck on their ceilings I totally did that So you have to ask as a member of the human species, how do they work? Some TV commercials claimed ‘magic’ But its really thanks to these chemical compounds called phosphors A phosphor is a substance that absorbs energy from another source, like a light for example And then emits that energy as visible light, which is the glow we see. There are natural phosphors in your teeth and fingernails, which is why they glow after absorbing energy from a blacklight But chemists have created lots of phosphors And the common ones in glow in the dark toys are zinc sulfide and strontium aluminate Zinc Sulfide is really safe and affordable which makes it great for mixing into plastics to make glow in the dark toys And both of these phosphors naturally emit green-ish light y’know, that pale, iconic hue But manufacturers can make other glow in the dark colors by adding different pigments to the plastic Because you energise these toys with light, whether it’s the sun or a lamp in your living room We say that they’re ‘photoluminescent’ But not all glow in the dark things work like that Glow-sticks, for example work by ‘chemiluminescence’ Which means that light is emitted as a product of a chemical reaction. When you crack a typical glow-stick You’re allowing a hydrogen peroxide solution to react with diphenyl oxilate This chain of chemical reactions releases energy, which is absorbed by electrons in fluorescent dye molecules that are also in the tube. That energy is emitted as photons of visible light And it’s a different color depending on the chemical structure of the dye molecules And some watches that glow in the dark work in a completely different way, through ‘radioluminescence’ But radioluminescence is rarely used nowadays Because engineers are developing better photoluminescent compounds for watches as well So if you’re the proud owner of a bunch of glow in the dark stars or enjoy snapping some glow-sticks on a dark night Hopefully, now, you have a better idea of how they work Thanks so much for asking And thank you especially to all of our patrons on Patreon who keep these answers coming If you would like to submit a question to be answered, Or get some videos a few days before everybody else, You can go to And if you just want to keep getting smarter with us, you can go to, and subscribe

100 thoughts on “How Do Toys Glow in the Dark?

  1. This channel: Pro:Makes you ask interesting questions. Con:They just recite wikipedia, add nothing else but pictures, and reap the benefits

  2. My watch has Tritium dots for the numbers. Before the half lives caught up to it, it glowed so bright, all night, that I had to put it face down on the bedside table.

  3. the heck, I saw this video on my phone and your skin colour just keeps going more pale or atleast more grey.

  4. Is it possible to be allergic to glowsticks? Once I went to an event with lots of glowsticks. A lot of them were smashed on the ground and some 'dust' got on my hand. I came home feeling a bit funny so I googled it to make sure it was nothing. I read it only had a few harmless chemicals and glass in it, and since I washed my hands I assumed I was fine. But I started finding it really hard to swallow and had moderate difficulty breathing. I remember my dad gave me something to eat and I was able to feel better after that. I learned afterwards that he gave me benadryl, a non-emergency allergy medication. Is it possible I was somehow allergic to something in the glowstick? Or maybe I inhaled small pieces of broken glass which irritated my throat. Anyone else have this experience?

  5. bis(2,4,6 trichlorophenyl) oxilate; 9,10 diphenylanthracene; diethal phthalate; sodium acetate and hydrogen peroxide.
    One of my favorite chemical reactions.

  6. Do tritium key fobs emit enough radiation when carried in your pocket during the day, every day for a decade or longer to be considered harmful?

  7. So, wait. Do the Phosphors take in the light from the sun (or wherever), which excites the molecules to vibrate (due to their unique chemical makeup), which so happens to emit a wave of energy within our visual spectrum as a sort of energy byproduct? Is that how it physically works? Or is there something happening that's not so intuitive?

  8. I've had a glow in the dark rubber wristband that is still glowing after 7 years and I don't know why or how

  9. I had made my peace with radiation, since that was the only way i could guess. And some of the old "glow in the dark" things where acctually radioactive.

  10. I love you guys. I'm a visual learner and I love science, you guys have taught me so much since I found your channel 🙂

  11. That did not explain how they work. Just the name of the compound and the name of the process. That's not really an explanation.

  12. when i was little i threw so many glow in the dark toys away because i didn't know that light recharged them.

  13. To continue on this luminescence theme, could you also cover electroluminescence that's often used in back-lighting of LCD displays and fancy Tron-like "lighting" that's used on cars, bikes and by some modern dance troupes?

  14. getting videos 'early' doesnt count, you still have to wait the same amount of time between videos as everyone else

  15. The reason HOW these compounds store light for so long would have been far more welcome than telling us what we already know and could find with 2 minutes of google searching!

  16. I used to have a little doll, some kind of dog/bunny thing, called Pj Sparkles. Which I proceeded to name, in my lack of imaginative 6 year old ways, Sparkles. That thing still glows in the dark and its been a good 20+ years.
    Not particularly relevant to the video but it reminded me of it.
    Great video!

  17. I'm so nerdy. I found a glow in the dark 3D solar system from about 9 years ago, completely freaked out, and hung it on my ceiling. Although I hit my head on Mercury every time I walk into my room, I love it so much. 😍

  18. I can just picture little Hank recreating the constellations on his ceiling, or else making up his own like one for John called 'Dorkus Major'

  19. so if glowsticks glow because of a reaction between elements, how does the manufacturer prevent them from reacting when they get fabricated?

  20. My watch has glow in the dark spots and hands but it's the type that needs "charging" with light to make it work for 30 minutes or so.
    So what's the point of it?
    Seriously, if I gotta shine light on it for it to glow for 30 minutes so I can see it in the dark……

  21. My mom used to buy me some of the stars. One day she got me a glowy castle set. We were talking one night and she thought she saw one if the stickers blink. The said they were demon possessed and then threw them away. 🙁

  22. People over here used to paint those watches at home and died of cancer as a result of the redioactive colour

  23. I don't like the glow in the dark stars anymore.. now I like saphire and proton beams and nickel reflector caps and hafnium rods with cobalt and americium.

  24. Can you please
    1. Talk more slowly, or
    2. Don't edit away the breaks you take for breathing.
    We are watching Youtube. There is no emergency here requiring you to put that much speed into things.

  25. Its been 10 years and I still have glow in the dark stars on my ceiling I love them like the video and like the comment if you love ceiling glow in the dark stars and other glow in the dark objects

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