A liter of light is an alternative lighting technique used to provide indoor lighting without electricity. To make a liter of light, people take an old 1-liter plastic bottle, fill it with water and a little bleach, then place it through a small hole in a roof. This can provide 55-60 watts of light per bottle — all without electricity. The way it works is that the water in the bottle refracts the sunlight from the outside, transmitting the light in all directions and providing a cheap, sustainable lighting source. The liter of light method has become increasingly popular in shantytowns and disaster areas where steady electricity is hard to come by.
More facts about alternative lighting:
A liter of light can be rigged up in about an hour and can last as long as five years.
More than 10,000 liters of light were installed in shantytowns in Manila, the capital of the Philippines, during a three-month period in 2011.
Liters of light also have become popular in Haiti, parts of the Middle East and Brazil.