What is the white powder in lightbulbs?

I noticed that the actual inside of the glass bulb is lined with a layer of white powder that wipes off real easily. what exactly is that stuff? and is it dangerous to get on your skin or inhale or something? some things say its just to even out the light, and some say its like some poisonous something or other that ignites? I have no idea. thanks :)

3 answers

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ANSWER #1 of 3

Depends if you're talking about a florescent or an incandescent bulb.

In fluorescent bulbs, the white powder is phosphor. Phosphor glows when electrons are passed through it, which is what makes a fluorescent bulb, well, fluoresce. Never, ever touch or inhale phosphor, as it is extremely toxic.

If you're talking about a regular incandescent light bulb that you would find in your home light fixtures, the powder coating the inside of the bulb is called kaolin, which is just a ground-up mineral. It is completely safe and not toxic in any way. It's only there to make the bulb opaque, and is, for all intents and purposes, just ground-up clay.


ANSWER #2 of 3

okay thank you so much I was kinda worried haha, but this was just a regular incandescent, so im good. Thankyou :)



ANSWER #3 of 3

There is lots of good info in mikeh's answer but the phosphor in fluorescent lamps is excited by ultraviolet light rather than electrons. Many white LEDs are actually blue or UV LEDs with phosphors to produce white light from UV. Things other than phosphor floures. Ever wonder how some laundry detergents get whites and colors so bright? The answer is fluorescence. Chemicals in laundry blueing and detergents convert UV to visible light so clothes literally glow. If you enjoy drinks with tonic water near "black" lights you might have noticed that your beverage glows since the quionine in tonic water mildly flouresces when hit with UV light. What we call fluorescent lamps are a type of mercury vapor bulb and the amount of mercury contained is small but toxic. When you break a bulb you should move everyone away, turn off fans, heaters, and air conditioning and open windows to let the area air out for a while before cleaning up.


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