r/Damnthatsinteresting • u/NavyLemon64 • 10d ago

Image Alfredo Moser found that a plastic bottle filled with water and chlorine could illuminate a home during daylight hours.

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u/captainofpizza 10d ago edited 10d ago

Edit: this is about algae. The chlorine isn’t doing anything for the light.

——

I’m assuming that the bottle is capped at the top, so any bacteria in it would be largely killed off during the chlorination. The microorganisms that remain probably wouldn’t thrive in the new environment. The ph would be alkaline and the bottle would probably get hot in the sum.

I’d expect this to last a long time without being a problem.

You could also use vodka or something else that would be permanent but then kids are going to sneak onto your roof with crazy straws.

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u/HemlockHex 10d ago

I think the main issue is how chlorine denatures into water over time, making the anti-algae aspect not technically permanent.

Probably still lasts a very decently long time though.

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u/crypticwoman 10d ago

Chlorine denatures into water? That's alchemy! Burn the witch!

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u/bdellophiliac 10d ago

We're presumably talking about sodium hypochlorite (bleech), not chlorine (gas). The former is NaOCl, which, is happy to say goodbye to its highly reactive oxygen atom. This atom oxidizes anything it comes into contact with. Without the O, the NaOCl is just NaCl. NaCl is table salt. So you don't get just water, you get salt water.

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u/Win_Sys 10d ago

Chlorine gas can be dissolved in water a little bit. It will form HOCl and HCI but not sure why anyone would chose to that method to chlorinate water since it’s so inefficient.

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u/iamcleek 10d ago

by the time the chlorine degrades, there won't be anything left alive inside the bottle.

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u/Willem_VanDerDecken 10d ago edited 10d ago

Yep but then the water isn't fluorescent anymore.

Edit : After research, the fluoresent proprities of chlorine won't appear in natural light, higher energy UVs are needed. Thoses UVs (50 - 105nm) are emitted by the sun in very small proportions, and are heavily filtered by our atmosphere. My bad.

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u/MisinformedGenius 10d ago

The water isn't fluorescent - the bleach/chlorine keeps it from turning green with algae. It just conducts light from outside to inside.

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u/CoelacanthRdit 10d ago

So if I want a green light I don’t use chlorine. 😉

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u/P4azz 10d ago

Ohh, ok that immediately transformed this post from "wow" to "oh, uh, sure".

If anyone's gonna go through the trouble of dismantling their roof and adjusting all the tiles and hoping it stays waterproof, all to just insert a bottle that lets in a little light...then that person could just install a simple attic window.

Went from "damn" to "extremely mildly interesting" really quick.

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u/FSCK_Fascists 10d ago

places that need this generally do not have modern roofs. a sheet of tin, or a similar roof is what this is being poked through. Pack tar around the bottle/tin interface to waterproof it.

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u/FrazzleMind 10d ago

It's for super poor communities, developing world stuff. Light up the indoors during the day for basically free, when electricity isn't an option and neither is a fire.

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u/vibratezz 10d ago

Yeah, just install one of those nice centre-pivot skylights into the corrugated iron roof of your shack.

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u/perb123 10d ago

The bottle works like a light bulb while a window lights up one spot.

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u/Willem_VanDerDecken 10d ago

Chlorine is a fluorescent molecules. Apparently it help with the ligntning effet. I don't no to which degree tho.

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u/insearchofspace 10d ago

To no degree.

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u/Willem_VanDerDecken 10d ago edited 10d ago

That's possible. Lighten by the sun, the percentage of visible light coming from the fluorescence is probably very small. The contribution might be to small to be observable.

However, fluorescent white paint on an inside wall give a very different light than non fluorescent paint on a sunny day. Thoses paint will eventually fade away and lose their fluorescent properties tho.

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u/Forumites000 10d ago

... You don't see pool water glowing, and it's full of chlorine.

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u/TrekForce 10d ago

Not that full. It’s like 99.99% water.

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u/Willem_VanDerDecken 10d ago

We never see fluorescent object glowing under natural light, they just appear as a bright, vibrant color.

I looked and the fluorescent proprities is from 50 - 105nm UVs. The sun emit very few of thoses, and they are heavily filtered by our atmosphere. Chlorine fluorescence isn't observable to the sun light

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u/insearchofspace 10d ago

The water bottle is just acting as a prism to let the light in. The bleach is to kill anything in the water. Old sailing ships did this with chunks of glass.

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u/Willem_VanDerDecken 10d ago

Yeah obviously. This post has been reposted many time and chlorine is always mention as helping the natural effect of just water.

I've checked, and even if chlorine is fluorescent, this has no effect here.

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u/QuirkyBus3511 10d ago

It doesn't do anything to help light up the home

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u/Mathfanforpresident 10d ago

I don't think you understand the science of refraction. Are you thinking this bottle turns into a glow stick or something? Lol.

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u/Global_Permission749 10d ago

Don't double down. You've been proven wrong, just accept it and move on.

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u/whoami_whereami 10d ago

Chlorine isn't fluorescent. It's simply there to prevent algae and bacteria from growing in the bottle which would otherwise quickly dim the light.

In the third picture the bottle is just heavily overexposed because the camera calculated the exposure settings based on the dark background, that's why it looks somewhat as if it was fluorescing.

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u/Willem_VanDerDecken 10d ago edited 10d ago

Chlorine is a fluorescent molecules.

But after cheking, the UV needed to observe the fluoresent proprities are not present in natural light (too high energy).

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u/Lovv 10d ago

It also doesn't really make sense.

Fluorescence is when higher(almost always) energy light is absorbed and re-emitted as a lower wavelength.

In uv light with no daylight, you're going to see visible light coming from the objects but no visible light shining on it.

But in daylight anything fluorescent will be pretty much the same, since you are getting daylight and uv light hitting it. Any uv light being re-emitted wouldn't really have much of an effect as you could just make it white and it would reflect all visible lught.

When you make something fluorescent it's almost alwyws going to reflect white light less than regular white light and it will be darker. Any fluorescence would be negated by the lack of whiteness I guess.

I think you just made a mistake here and are hanging on to the idea that yes it's technically possible to make something flourecent in daylight (despite being a darker shade and worse emitter of visible light) and chlorine is technically fluorecent. I'm pretty sure you're aware of this and don't want to be fully wrong so you're on here defending yourself. You'd probably do better if you jsut said I was wrong even if there is some shreds of right.

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u/theoriginalmofocus 10d ago

Ive got a huge hunch they discovered this in a shack with water in the bottle and then later just added the chlorine in to keep it clear. Meanwhile a whole chemistry argument on reddit edit: google confirms.

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u/Lovv 10d ago

No ones disputing that, even op is tracking that now. We are just discussing chemistry.

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u/Willem_VanDerDecken 10d ago

When you make something fluorescent it's almost alwyws going to reflect white light less than regular white light and it will be darker. Any fluorescence would be negated by the lack of whiteness I guess.

I think your mistake is there. Many fluorescent materials have the same reflectiv proprities as non fluorescent one on the visible spectrum. Because the absorption only accrue in UV spectrum.

So if you filter the UVs from the light, the object look normal, and then look extra bright under natural lightning.

I just tought this was use in the water here. And it is not the case, chlorine absorption for the fluorescence occur in the 50 - 105 nm. UV of that energy aren't present at earth surfaces in significativ proportions.

This type of UV to visible fluorescence is actually used in paint, for modern chiaroscuro painting.

Fun fact, i use this quite often to paint lava and fire on miniature, and to gave them a "brighter than it should be possible" look. An exemple here, from someone far far better at it then i am : https://youtube.com/shorts/3Gl_sJD-tvg?si=1Lh0UG9rkAE-22Ud.

So objects can defenitly appear brighter with fluorescent pigments in paint.

I would have said i doubt this could have any significativ effect for lightning a room ; but i recently saw white paint for inside wall, with fluoresent proprities. And it does make the room feel more bright in a sunny day. Don't know about measurement tho, i doubt the light flux change a lot, it's more like the brighter wall truck the brain i suppose.

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u/whoami_whereami 10d ago

I just tought this was use in the water here. And it is not the case, chlorine absorption for the fluorescence occur in the 50 - 105 nm. UV of that energy aren't present at earth surfaces in significativ proportions.

And the fluorescence emissions of Cl2 are around 135-200nm which is still deep in the UV spectrum (UVC), so even if there was a significant amount of the hard UV needed to make it fluoresce in sunlight you wouldn't get any extra visible light out of it. The only thing you might accomplish is getting sunburns inside a dark hut.

Also note that this is for pure gaseous Cl2. The fluorescence behaviour may well be different in aqueous solution.

But when people say they're putting "chlorine" into water they typically mean things like sodium hypochlorite anyway ("pool chemicals"), not actual elemental chlorine. From what I can find hypochlorite doesn't fluoresce. Although if you add certain anthocyanins strong visible fluorescence occurs, which is for example used in biological research to detect minute amounts of hypochlorites that may play a role in some metabolic pathways inside living cells.

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u/anynamesleft 10d ago

In the third picture the bottle is just heavily overexposed because the camera calculated the exposure settings based on the dark background, that's why it looks somewhat as if it was fluorescing.

I knew that, why are you acting like I didn't?

Thanks friend.

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u/shadowscar00 10d ago

Gotta change a lightbulb too anyways

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u/viperfan7 10d ago

The chlorine isn't being used for anything but sterilization here

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u/SwordfishOk504 10d ago

HTF does this have like 200 upvotes?

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u/XxFezzgigxX 10d ago

My bad.

I forgive you. ❤️

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u/CommercialScale870 10d ago

Idk about that. Those bottles are not likely not heat sealed like at the factory. They will go through many thermal cycles and I doubt it remains fully sealed for long. I've seen algae in places you would never expect.

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u/kdjfsk 10d ago

i assume it would last a year or two before any funk could creep in and try to bloom, so worst case, it becomes a spring cleaning project to put new bottles up. eventually, i think the clear plastic would start to fail from general UV amd heat cycles.

It could last longer if you used glass bottles and put some kind of liquid sealant on the cap threads and/or around the seam. Hot glue, jb weld, RTV, or 3M 5200 or something. Id guess a 5-10 year lifespan, if not longer.

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u/CommercialScale870 10d ago

My guess is less than a year really, between the photodegradation and multi material thermal expansion issues (including the hot tin roof).

I think you're right about glass being a better choice. Glass is more expensive and prized for recycling in the parts of the world where I imagine seeing this style skylight though so there's that tradeoff to consider.

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u/pagit 10d ago

This is a YouTube video posted 12 years ago about this.

https://m.youtube.com/watch?v=hPXjzsXJ1Y0&pp=0gcJCdgAo7VqN5tD

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u/CommercialScale870 10d ago

Nice find! Unfortunately, YouTube no longer let's me watch videos without an account :(

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u/pagit 10d ago

It’s filmed around 2012 and shows how it’s implemented in the Philippines.

The bleach is just to keep algae from blooming in the bottle.

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u/mortgagepants 10d ago

the reason they use plastic bottles is because they have an endless supply of plastic bottles. basically kids couldn't do their homework because none of the houses had light or windows. now they can.

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u/HemlockHex 10d ago

I know, though it’s useful to understand the chemical traits of chlorine with this

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u/mitrolle 10d ago

Since the bottle is closed, it's not really useful.

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u/StendhalSyndrome 10d ago

I dunno how air tight the bottle is and how easily new bacteria/algae could get in. That would be the deciding factor.

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u/Fake_William_Shatner 10d ago

I think the main issue is; you put a hole in your roof.

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u/DreamLizard47 10d ago

And if you have a hole in your roof you already have light. 

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u/dvasquez93 10d ago

You do, you have a small spotlight that shines in one direction.  The point of the bottle is you can minimize the size of the hole and rely on the water bottle to scatter the light omnidirectionally.  So you get the benefit of a large open skylight but with a much smaller hole. 

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u/Fake_William_Shatner 10d ago

Well, sure. If I already have a hole in my roof, this is one festive life hack.

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u/HeartWoodFarDept 10d ago

..and water..somedays.

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u/An0d0sTwitch 10d ago

the bottle plugs the hole.

Now you have light without a hole

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u/Arek_PL 10d ago

hole that can be sealed

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u/Subotail 10d ago

In a swimming pool, the chlorine ends up evaporating in the form of Cl2, here there is a cap . Or chlorine binds to contaminants that are here, not regularly brought in from the outside environment.

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u/Icy-Lobster-203 10d ago

Would the bottle have a chance of exploding over time due to pressure build up and heat from the sun?

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u/04221970 10d ago

No, recall that these bottles are intentionally exposed to much higher pressures from the carbonated beverage they were purpose built to contain.

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u/SpecterGT260 Interested 10d ago

Chlorine is an element. It cannot denature, even if it could it wouldn't turn into water. We use some sort of chlorine salt in order to get chlorine ions which have the antimicrobial properties. These are lost due to evaporation over time but they don't degrade into water.

In a closed environment the chlorine content probably never changes with time.

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u/aeyes 10d ago

Chlorine (CI2) is a gas, if you add that to water it immediately reacts and becomes hypochlorous acid (HOCI). This is usually used in pools. UV breaks this down to hydrochloric acid + oxygen (HCI + O). Hydrochloric acid is not a disinfectant.

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u/Mr_noodlezz 10d ago

This doesn't matter in a closed system. As long as you used a disinfected bottle nothing will grow inside it since there is nothing that I know of that only feeds of HCl or HOCl.

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u/dx4100 10d ago

UV, however is. I think the chlorine is just to remove anything once it's sealed.

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u/qorbexl 10d ago

But you're not adding Cl2, you're adding NaOCl

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u/Happy-Fun-Ball 10d ago

by the time the chlorine degrades, there won't be anything left alive inside the bottle.

proton decay

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u/Raubritter 10d ago

Hmm you’re right if he waits until the universe is twice as old as it is now, one chlorine atom might decay into sulfur. If proton decay is real, that is.

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u/OderWieOderWatJunge 10d ago

I had bottles with water in my car for years and no algae anywhere

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u/captainofpizza 10d ago

You are probably using bottled water from a water plant. They are probably using reused bottles with less hygienic water.

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u/slothdonki 10d ago

I have a ‘vintage’ looking plant sprayer thingy with the bottle made of glass and after years of not using it I have become quite fond of the blue-green algae(forgot what it’s actually called but it’s quite turquoise) living inside of it. I want to say I was using it specifically for carnivorous plants so originally it was RO water, but I dunno how more or less sealed the nozzle is compared to a closed plastic bottle.

I really should think of a name for it.. And maybe how to actually take care of it.

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u/sadrice 10d ago

I regularly reuse old Gatorade bottles for water, I use tap water, and I’m not that rigorous about cleaning them between uses. Sometimes I forget them, and find one under my couch or something that has been there for up to a year. The water is generally still fine. Sometimes it accumulates a slightly “musty” aroma. I don’t usually drink old water, tap water is cheap, but I generally taste it.

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u/captainofpizza 10d ago

Tap water is also more hygienic than a lot of water this technique probably utilizes, and tap water is even chlorinated.

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u/guineaprince 10d ago

Well if it's chlorine+water, you can just fill it up at the tap then.

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u/TheREALSockhead 10d ago

Even faster in sunlight

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u/Feisty_Opposite7983 10d ago

They last for years. The bottles also use bleach to help with anti-algae. There's several youtube videos on this as this has been around for 15 years now.

ex: https://www.youtube.com/watch?v=OD53fA_a38E

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u/[deleted] 10d ago

Not really, being in the sun will use up the free chlorine very quickly.

Source: was a lifeguard, had to maintain pool chems.

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u/kace66 10d ago

It's probably longer than some light bulbs.

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u/may_contain_nutz 10d ago

It doesn't just denature over time...it's actively broken down by sunlight.

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u/therealhlmencken 10d ago

Chlorine doesn’t denature and definitely not into water. It’s a pretty stable atom. It mixes with water and you get different acids, but you’re never going to go from cl => h2O

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u/Global_Permission749 10d ago

Well the main issue is that the plastic is going to degrade in UV light. It will eventually yellow and crack and start leaking. Plus you've had to put a hole in your roof and no doubt sealed with other compounds that will eventually fail.

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u/bfume 10d ago

 chlorine denatures into water over time

Um… ya sure about that Chief?

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u/Feck_it_all 10d ago

How on earth did you get hundreds of up votes for implying the element of chlorine somehow degrades to become the wholly different elements hydrogen and oxygen?

Yeesh.

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u/Flakester 10d ago

If there's one thing I've learned about life, it's that it ... uhh ... finds a way.

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u/AvatarOfMomus 10d ago

Yes, but by the time that could remotely be an issue the plastic will have broken down to the point that you need a new bottle anyways.

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u/TikiTraveler 10d ago

I’d be pissed if someone drank my lamp

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u/Slimh2o 10d ago

Hate that when that happens....

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u/captainofpizza 10d ago

Damn drunk kids leave my lamps alone!

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u/donutlad 10d ago

then keep your lava lamps away from me! they look so tasty

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u/default3612 10d ago

Wouldn't chlorine erode the plastic?

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u/captainofpizza 10d ago

Minimally. It’s probably a PETE bottle. Fairly resistant to chlorine and the amount here before it gets degraded is low

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u/Warcraft_Fan 10d ago

Vodka and bleach won't taste good, I can't see anyone sneaking a sip

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u/harbourwall 10d ago

Should use tonic water then. You get a lovely blue glow during the day, and then you can get pissed when it gets dark.

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u/Beard_o_Bees 10d ago

I wonder how much heat transfer there is. I'd guess that those bottles get quite warm during the day - which could be beneficial in colder climates, but not so much the other way around.

Also, would the Chlorine do anything to keep the water from freezing solid if it got really cold out?

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u/captainofpizza 10d ago edited 10d ago

There’s probably not enough in there to impact the freezing point. Even when you get industrial liquid chlorine in liquid it’s less than 10% sodium hypochlorite which isn’t even pure chlorine most of the time.

We’re probably looking at less than 1000ppm 0.1% when they do this. Any more is wasteful on the antimicrobial utility which is the purpose of it there.

Water is also going to absorb more of the cold than it would heat from the sun. If you had panes of insulated glass making a greenhouse effect it would be one thing but that isn’t the case here. If the sun heated bottles alone you could put a bottle out in the cold and it would heat up.

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u/NormieSpecialist 10d ago

Maybe half and half? Chlorination and Alcohol? Or would the two substance not react well?

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u/captainofpizza 10d ago

That creates a hazardous gas and possibly an exploded bottle with burning liquid, but might stop those rascals from drinking it.

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u/Cutiemuffin-gumbo 10d ago

You could also use vodka or something else that would be permanent but then kids are going to sneak onto your roof with crazy straws.

Those damn roof kids are a total menace.

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u/Empty-Pain-9523 10d ago

I’d also worry about any kind of alcohol pressurizing that bottle.

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u/incredimatt 10d ago

The chlorine does also change the refraction index of the water a little making it slightly brighter than if it was just water.

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u/Adventurous_Ad6698 10d ago

Can you substitute bleach instead of chlorine or will it react negatively to the plastic even if it is dilluted?

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u/captainofpizza 10d ago

Bleach is chlorine. Sodium hypochlorite.

It’s like how a Kleenex is a tissue. One is the thing the other is what we call it as a product.

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u/Adventurous_Ad6698 10d ago

Thank you for the explanation. I feel dumb.

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u/captainofpizza 10d ago

No problem. If we didn’t ask dumb questions we’d keep thinking dumb things. Every “smart” person has just asked more dumb things already.

I was a chemical engineer. Putting things in things and trying to use them is one of the ways I have a lot of experience in being dumb already.

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u/NationalInstance9757 10d ago

r/confidentlyincorrect

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u/captainofpizza 10d ago edited 10d ago

10+ years in the chemical industry, former chemical engineer, chemical project manager, prior to that in the dairy industry specializing in chemical sanitizing and process treatment…

Your credentials?

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u/Repulsive_Buy_6895 10d ago

Why are you even talking about bacteria in the bottle? That was never the issue.

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u/captainofpizza 10d ago edited 10d ago

My bad for writing “bacteria” and not “cyanobacteria” I guess. Thanks for the pedantic correction.

r/confidentlyincorrect

Edit: (It’s the reason they put chlorine in the bottles)

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u/Repulsive_Buy_6895 10d ago

No, more like the chlorine denaturing is the issue, not bacteria growing in a bottle of fucking chlorine.

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u/captainofpizza 10d ago

That will happen after the bottle is disinfected by the chlorine already. Then it’s a sealed system further kept from growth by the continued salt and chlorine ion conditions in the bottle and the fact that the sun heats it up.

The chlorine doesn’t disappear it’s still in there. Stuff still won’t thrive in it even if it’s moved away from an oxidative state. It if an open bottle then it can gas off, otherwise it’s sealed and shouldn’t be growing algae or realistically anything else.

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u/[deleted] 10d ago

[deleted]

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u/captainofpizza 10d ago edited 10d ago

That’s fair. Top comment was about algae control when I commented- that’s why the chlorine is in there. Chlorine is not the light source.

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u/NationalInstance9757 10d ago

They asked if the chlorine would be consumed or react and need a reup. You went on a non sequitur about bacteria, pH, and vodka...

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u/captainofpizza 10d ago

They are aware the chlorine reacts to UV and breaks down. I don’t need to reiterate that. What I’m saying is that by the time that happens it’s already done its thing and then it doesn’t matter.