# New toy: black light LED keychain. What cool things fluoresce?
**URL:** https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919
**Category:** Factual Questions
**Created:** [March 18, 2006, 6:09pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919 "2006-03-18T18:09:22Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Fish](https://boards.straightdope.com/u/Fish)
#### Post date: [March 18, 2006, 6:09pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/1 "2006-03-18T18:09:22Z")
I think I spelled that right. I just keep adding Us into “fluourueuesucue” until it louoks riguht.
Anyway, I have found several things which appear fluorescent under my black light LED keychain: motor oil was the most unexpected. (It looked greenish-yellow.) Also there are the regulation number of orange price tags, and a few products (and magazines) use fluorescent ink on their labels and covers.
An unwashed dish in the sink (a teacup with some icky water in it) appeared to be filled with glowy yellow water.
The deposits on the showerhead also glowed; not sure what’s in that water, but I’m glad I have Culligan bottled stuff at my house.
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [March 18, 2006, 6:19pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/2 "2006-03-18T18:19:37Z")
Depends on the primary emission wavelength. Most of the UV LEDs I’ve seen in consumer products are 370-380 nm, which is just barely in the UV. If you want to see more things fluoresce, you want to try to find shorter-wave ones. I’ve seen between 320 and 360 nm, and I believe Nichia has produced a 200 nm LED. Of course, with these shorter wavelengths, you have to be increasing cautious, since the potential risk of retinal and corneal damage becomes greater with shortwave UV. I have a few 380s sitting around, and you can get quite a few things to fluoresce with it. Regular unflavored Chapstick fluoresces an eerie green, for instance.
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### Author:  [@Fish](https://boards.straightdope.com/u/Fish)
#### Post date: [March 18, 2006, 6:27pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/3 "2006-03-18T18:27:57Z")
Ooo, Chapstik. Gotta try that.
I don’t have the package here with me at work, shh so I can’t tell the wavelength. I assume it can’t be very far into UV range since I can actually see a purple glow.
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### Author:  [@Bearflag70](https://boards.straightdope.com/u/Bearflag70)
#### Post date: [March 18, 2006, 6:29pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/4 "2006-03-18T18:29:15Z")
semen stains
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### Author:  [@HMS\_Irruncible](https://boards.straightdope.com/u/HMS_Irruncible)
#### Post date: [March 18, 2006, 6:32pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/5 "2006-03-18T18:32:49Z")
Go outside at night and shine for scorpions. Apparently the surface of their exoskeleton glows green unless they’ve moulted very recently.
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### Author:  [@Fish](https://boards.straightdope.com/u/Fish)
#### Post date: [March 18, 2006, 6:33pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/6 "2006-03-18T18:33:57Z")
The unflavored Chapstik _container_ (the black label) glows green, but the Chapstik does not. Awwww.
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [March 18, 2006, 6:41pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/7 "2006-03-18T18:41:23Z")
> [@Fish](#):
>
> The unflavored Chapstik _container_ (the black label) glows green, but the Chapstik does not. Awwww.
:smack: I forgot to mention what’s probably the important part. It’s the _medicated_ variety, which contains menthol and camphor. Those are probably the components which fluoresce. Sorry 'bout that.
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### Author:  [@Rick](https://boards.straightdope.com/u/Rick)
#### Post date: [March 18, 2006, 7:13pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/8 "2006-03-18T19:13:22Z")
> [@Fish](#):
>
> I think I spelled that right. I just keep adding Us into “fluourueuesucue” until it louoks riguht.
>
> Anyway, I have found several things which appear fluorescent under my black light LED keychain: motor oil was the most unexpected. (It looked greenish-yellow.)
Probably not the motor oil, but rather a dye that is added to trace oil leaks. Blacklights can find the source of an oil leak that is all over everything.
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [March 18, 2006, 7:24pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/9 "2006-03-18T19:24:18Z")
> [@Rick](#):
>
> Probably not the motor oil, but rather a dye that is added to trace oil leaks. Blacklights can find the source of an oil leak that is all over everything.
I wasn’t aware they added a fluorescing dye to engine oil. I know there is one in brake fluid, however.
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### Author:  [@Hunter\_Hawk](https://boards.straightdope.com/u/Hunter_Hawk)
#### Post date: [March 18, 2006, 7:26pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/10 "2006-03-18T19:26:53Z")
And there’s tonic water, of course. It might be interesting to do a sweep through your fridge and pantry to see what other edibles might fluoresce.
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### Author:  [@SnakesCatLady](https://boards.straightdope.com/u/SnakesCatLady)
#### Post date: [March 18, 2006, 7:31pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/11 "2006-03-18T19:31:43Z")
Don’t know if you’d be interested, but ringworm glows under a blacklight. So does cat urine.
(can you tell I have worked for a vet?)
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### Author:  [@Rick](https://boards.straightdope.com/u/Rick)
#### Post date: [March 18, 2006, 8:00pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/12 "2006-03-18T20:00:56Z")
> [@Q.E.D.](#):
>
> I wasn’t aware they added a fluorescing dye to engine oil. I know there is one in brake fluid, however.
Pretty much every fluid that goes into cars has a dye that can be added for fault tracing. A/C and engine oil are probably the two most popular. I was unaware of brake fluid having a dye, I thought it was just naturally fluorescing.
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [March 18, 2006, 8:11pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/13 "2006-03-18T20:11:52Z")
Are the dyes different colors, so that they can be distinguished readily? It may be the case that brake fluid fluoresces naturally; I’d always heard it was a dye. I searched briefly, but couldn’t find anything definitive. I bet **Una** would know.
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### Author:  [@Rick](https://boards.straightdope.com/u/Rick)
#### Post date: [March 18, 2006, 8:25pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/14 "2006-03-18T20:25:33Z")
I’m honestly not sure about that.
Even if they were the same colors it’s just like real estate location, location, location. If the condensate drain from inside the car has traces of dye, it isn’t the brakes that are leaking. 😃
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### Author:  [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)
#### Post date: [March 18, 2006, 8:29pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/15 "2006-03-18T20:29:53Z")
> [@Rick](#):
>
> If the condensate drain from inside the car has traces of dye, it isn’t the brakes that are leaking. 😃
That, or you’ve got a REALLY bad mechanic. 😉
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### Author:  [@rjk](https://boards.straightdope.com/u/rjk)
#### Post date: [March 18, 2006, 11:49pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/16 "2006-03-18T23:49:46Z")
Coffee was mentioned here quite a while ago as glowing nicely. I think it was in a practical-joke thread - if somebody passes out at a party, draw on his face with coffee, and make sure the bathroom is fitted with a black light.
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### Author:  [@Scissorjack](https://boards.straightdope.com/u/Scissorjack)
#### Post date: [March 18, 2006, 11:52pm UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/17 "2006-03-18T23:52:30Z")
Free And Lovely shampoo shows up nicely.
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### Author:  [@Zabali\_Clawbane](https://boards.straightdope.com/u/Zabali_Clawbane)
#### Post date: [March 19, 2006, 12:01am UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/18 "2006-03-19T00:01:01Z")
Pert shampoo too.
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### Author:  [@Zabali\_Clawbane](https://boards.straightdope.com/u/Zabali_Clawbane)
#### Post date: [March 19, 2006, 12:08am UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/19 "2006-03-19T00:08:24Z")
Er, I think it has to be Pert Plus on second thoughts, to clarify.
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### Author:  [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)
#### Post date: [March 19, 2006, 1:19am UTC](https://boards.straightdope.com/t/new-toy-black-light-led-keychain-what-cool-things-fluoresce/348919/20 "2006-03-19T01:19:53Z")
Where can you buy a _good_ one o these online, cheap?
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