Soda Bottle Light

Via Andrew Sullivan, Liter of Light, a great program bringing light to the dark shanties of third world slums:

When filled with water (with some bleach to keep out the algae) and snugly inserted into custom-cut holes in a roof, plastic bottles refract the sun's rays, scattering about 55 watts of light across a would-be pitch black room. The new lighting source can be rigged up in less than an hour, and it lasts for five years. ... Illac Diaz, the social entrepreneur behind the project, told Reuters that the sustainable and inexpensive light source can boost "the standard of living across the board for the bottom 90 percent of this country." Another woman said she hopes to save 23 dollars per month.

Before cheap window glass and electricity, interior spaces were dark most of the time. In many third world slums people still live that way, because their roofs are made of corrugated metal, the shacks are too close together for windows to let in much light, and electricity is too expensive. But our world is full of transparent materials, and some of them, like plastic soda bottles, are practically free. What a wonderful idea.