LITER OF LIGHT
low-cost light tube using bottel , water & sunlight
Liter of Light is a global, grassroots movement that uses inexpensive, readily available materials to provide high quality solar lighting to people with limited or no access to electricity.
The Liter of Light is both a day and night solution that provides passive daylight as well as solar nightlights such as lanterns, house lights, and streetlights. The solar bottle bulb is a simple device consisting of a 1.5–2 litre plastic bottle filled with water plus a little bleach to inhibit algal growth and fitted into a hole in a roof to refract sunlight. The device functions like a deck prism: during daytime the water inside the bottle refracts sunlight, delivering about as much light as a 40–60 watt incandescent bulb to the inside of the house. One solar bottle bulb helps prevent carbon emissions of up to 200 kilos and can keep working for as long as five years