A Liter of Light

The solar bottle bulb is taking the developing world by storm bringing sustainable, affordable lighting to the underprivileged rural communities in a number of regions around the globe, the concept is cheap, simple and most importantly sustainable, but how did such an amazing idea come about? The concept was first conceived in 2002 by Alfred Moser, a mechanic in SAA Paulo, Brazil, to light his workshop when his neighborhood was suffering energy shortages, enabling him to continue working.

His neighbors, intrigued by the idea, soon started following suit, adding the bulbs to heir homes in kitchens, bathrooms and living areas where electric light was prohibitively expensive and inefficient. The bottle bulb revolution was then further enhanced by The “Mystery Foundation”, which runs a program in the Philippines called “sang Lilting Lillian: a Liter of Light”. Based on a project developed by students at MIT under the Appropriate Technologies discipline, the project aims to bring sustainable, affordable lighting to the underprivileged rural communities in the country.

A Liter of Light aim to bring light 1 million homes using this green genealogy not only in the Philippines but in shantytowns in India, Africa and other southeast Asian countries, by the end of 2012. Solar bottle bulbs are usually made out of 2-L bottles, use no electricity and produce the same amount of light as a 50- to 60-watt incandescent bulb, there is no leakage and the bottles can stay there for years without any need for maintenance! The water bottle lights are said to last for 5 years.

The concept seems so simple but how does it work? The lights work by refracting sunlight in a 360-degree arc around the room, which provides superior light to a window or skylight, only allowing light into a room in a erect beam. The bleach keeps the water clean and clear by preventing algae growth. So what’s the science behind the concept? When light moving through the air runs into a denser medium such as water, it changes direction because of refraction.

The light beam “bends” when it enters the so that it’s traveling more directly down into water. That’s very helpful if you’re trying to get more light to go down through the bottle into a dark room below. Despite this, some of the light will still be on a path to the opposite side of the cylinder. A portion of the light is trapped in the cylinder because of simple reflection.