Two-liter plastic bottles filled with water, bleach illuminating Kenya's slums; 'water bulb' discovered in Brazil in 2002 now in at least three continents, will brighten 1 million homes by 2012 in the Philippines

NAIROBI, Kenya , November 24, 2011 () – In this maze of windowless tin shacks, school classes are often held outside because even in daytime it’s too dark to see the blackboard. Now a youth group is hoping some two-litre plastic bottles filled with water and bleach can brighten Kenya’s slums.

The soda-bottle-as-light-bulb was discovered in Brazil by mechanic Alfredo Moser in 2002. In the decade since, tens of thousands of people who can’t afford electricity or other sources of light such as candles have converted to the so-called water bulb.

A youth group called Koch Hope has been so successful in installing water bulbs in Korogocho, one of Nairobi’s largest slums, that it is struggling to meet demand. The group installed the first 100 bulbs for free in April in the hope of attracting attention from donors and expanding the project.

When a bottle is hung through a hole in the roof and filled with water and bleach, it refracts sunlight and can produce as much light as a 50- or 60-watt bulb.

Veronica Wanjiru, 24, a mother of two, said even illegal electrical hookups, candles and paraffin are too expensive for many in Korogocho.

Her 11-year-old and five-year-old had to do their homework outside and in a rush before the sun set. Now that she has a water bulb, it can even produce light at night during a full moon.

“Before they put it in, my children would sometimes use candles, but after they had finished they would forget them, which can even burn the house,” she said.

Matayo Magalasia, one of the few people from Korogocho to go to college, saw Mr. Moser’s invention on the Internet last year and sought to replicate it. He approached Koch Hope about bringing light to Korogocho.

“I grew up here and I knew the houses were dark even during the day. I had to do my homework outside because we did not have light,” Mr. Magalasia said.

Paul Jumbi, 28, a member of Koch Hope, said the group hopes to install the water bulb in every house in Korogocho and then expand to other Nairobi slums. Mr. Jumbi, though, said the project’s expansion has been curtailed by a lack of money.

The plastic bottles are easy to find, but buying the sealant to put around the hole in the iron roof where the bottle sits is expensive.

Mr. Jumbi said their first attempts to install the water bulb were met with resistance from people who thought the hole would let in rainwater.

He and his team persuaded the owner of a primary school where students were being taught outdoors because they could not see the blackboard inside. Installing it in the school led other residents to buy in to the idea.

During electricity shortages in Uberaba, Sao Paulo, in 2002, Mr. Moser discovered that hanging a plastic bottle full of water from his roof brought in extra light. The idea behind Mr. Moser’s simple invention – also known as a solar water bulb – has spread to slum dwellers in at least three continents.

In the Philippines, a non-governmental organization is attempting to use the water bulb to brighten one million homes by next year. The project is known as Isang Litrong Liwanag, which translates to A Litre of Light.

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