In some countries, being able to turn on a simple lightbulb is a luxury - one few people can take advantage of. There's an initiative in the Phillipines, though, that I thought was quite cool. You need a simple water bottle, filled with water with a bit of bleach added, and then the bottle is pierced through the roof. In essence, the sun will beam down, hit the top of the bottle, and then light up the entire room.
They say the bottle can reach about 60W, but it's hard to tell in the video just how effective it really is (the room still looks pretty dark even with the bulb, but it could have just been difficult to capture on camera).
Either way, a lightbulb that costs just $1 and could effectively last forever is beyond cool.
http://www.bbc.co.uk/news/world-asia-pacific-14967535
They say the bottle can reach about 60W, but it's hard to tell in the video just how effective it really is (the room still looks pretty dark even with the bulb, but it could have just been difficult to capture on camera).
Either way, a lightbulb that costs just $1 and could effectively last forever is beyond cool.
http://www.bbc.co.uk/news/world-asia-pacific-14967535