How To Turn a 2-liter Bottle Of Water Into a 50-Watt Lightbulb

By Paul Michael on 6 April 2009 (Updated 10 May 2009) 22 comments
Photo: Paul Michael

It's not often that I'm taken aback by the simplicity and power of an invention, but this one does it for me. It's cheap, anyone can make one and it literally changes lives. Welcome to the water-bottle lightbulb.

The inventor's name is Alfredo Moser, and his idea is spreading like wildfire through his neighborhood in Brazil. Like all really great ideas, it was born out of necessity. During a 2002 energy blackout in Brazil,  Alfredo's workshop was plunged into darkness. And so, using a simple 2-liter bottle of water, two capfulls of bleach and an old 35 mm film canister, he created this lightbulb.

By cutting holes in his workshop roof, the new water-bottle lightbulbs could shine the sun's rays directly into his dark workplace, bathing it in light that enabled him to work again. And friends and neighbors have been using his invention to light their homes without having to pay for electricity. Obviously, this isn't a solution for your average home in America, but it could easily work in your garden shed or another type of workshop. And I'm sure there are a few enivronmentalists looking at this very closely right now, including the creator of Earthships.

A few naysayers out there have already started picking apart the invention, with the main (and obvious) drawback being that it doesn't work without sun. Well, that's true. But this is designed to light up dark rooms during the daytime without spending one cent on electricity. And in the places where this invention is most useful, money is not exactly in abundance. It's a great idea and I, for one, salute Alfredo for a marvelous invention. Much like Trevor Bayliss's wind-up radio, I can see this having a huge impact, especiallly in third world countries.

 

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Guest's picture

The video is interesting, especially the final scene where they showed a "before" and "after," but for the most part it doesn't explain how it actually works. What does the bleach do in the process? How does one really make it? Why do you need to "cover the cap"? Why does one need water/bleach in there at all, rather than just a plastic opening to let sunlight in? Still, it's great that this innovation has been introduced....

Guest's picture
Charm

The bleach is used to keep the water in the bottle cleaner and keeping it that way. The cleaner the water the best result you'll get.

Guest's picture
Guest

The bleach might be to keep the water "fresh".

Guest's picture
Guest

Necessity is the mother of invention... great post... hopefully here in the USA and other "developed" countries more people will actually start looking for greener ways to improve our daily lives that, like this one, will keep more green in your pocket!!! Don't buy into the green hype with your hard earned money!!!

Guest's picture
Brian

...is considered a new idea. It isn't. Seafarers have used deck prisms...essentially the same thing, just in glass...since the 1800s, and an quick walk through an old neighborhood in any major city will probably uncover dozens of instances of glass cylinders set in the sidewalk to provide light for cellars.

Props to the guy for using water bottles. It's a great idea. But the idea ain't new.

Guest's picture
lucille

I think the water helps to prism the light so your getting more light than from a simple covered clear hole in the ceiling. What I could not tell was how they held them in the ceiling.

The only problem I could see is they would freeze in northern areas.

Guest's picture
Alan Trulock

I wouldn't exactly call it new though. I should go put some tube skylights in my bathrooms.

Guest's picture
wildgift

These are simple skylights, but, way cheaper. There's a brand called solatube that does something similar, but it's more expensive. The top of the bottle and the water probably bend the light so it goes downward. The water may condense on the inside of the bottle, forming tiny half-spheres that would diffuse the light.

Guest's picture
Guest

i think thats a good idea. they could make decorative containers of water to use when the sunlight permits and reserve the electricity for night time

Guest's picture
Guest

out. Witch is an important task in brazil...
Just put a glass tile would give about the same light ( I have used that...) but it makes a small room hot really quick in tropical zones.

So its a really good idea to have a small intake and to spreed the light.

Guest's picture

Just goes to show you-- Necessity is the mother of invention . . .

Guest's picture
Olivia

Sort of the same thinking that went into solar cookers. I love this kind of stuff, making something from nothing.

Guest's picture
Linda

The water bottles are a great idea if you don't have a problem with leaks. The bleach is to keep the water from growing algae and therefore turning green/cloudy/moldy and not shining the sunlight through it. The water is to diffuse the light. The cap cover was so the sunlight aka UV light didn't tear up the cap quickly.

As far as the earthships--great idea, except you need to research what you are putting into your walls. My hubby is a chemical engineer with a lifetime of dealing with automotive tires. Synthetic rubber has in it butadiene which will leach out into your house. It's not a good idea. Read about it here: http://www.atsdr.cdc.gov/tfacts28.html. Be careful of toxicity of your house because you spend a lot of time there and you don't want to breathe toxic gases or have anything that will cause cancer or organ failure down the line. You may not even be able to smell or sense some things that are bad for you.

Carlos Portocarrero's picture

Brilliant idea and brilliant post. Well done!

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Guest's picture

I use dial-up so I'm wondering if the poster or one of the commentors plans on making a howto for those of us unable to watch ?

Guest's picture
Guest
Guest's picture
Guest

Wouldn't "Water-filled Tubular Skylight" be a more accurate description that "50-Watt Lightbulb"?

Guest's picture

It's the simplest ideas that so often are the best.

Guest's picture
Guest

Funny, just saw this same idea on YouTube about a man in the philippines who also apparently invented the idea for poor areas that don't get electricity.

Guest's picture
Guest

they used something similar on ships in the 17 and 1800's I think, it was a cone shaped piece of glass that went through the deck

Guest's picture
Sujit Varadhan

hey guys.... Does this thing last after sunset?.... maybe for sometime?

Guest's picture
Guest

Stop referring to this innovative idea as a lightbulb! It is not. Skylight, yes. Light generating device, NO!