I have JUST come across this wonderful idea...and I am wondering how children can participate to grow the project. Here's an explanation of the idea from Sustainablog.
You can also link to a short video of the idea in action here
An ingenious solar lighting idea that works in the day time is spreading across low income areas in the Philippines. This solar light design requires neither a solar panel nor a light bulb, however. In fact, all it requires is the sun and a two liter water bottle.
Image Credit: Isang Litrong Liwanag
Light bulbs are only for the very fortunate in the Philippines, as they are not as easily or readily accessible. You can imagine the difference a little bit of light would make in a place where it is hard to find or expensive to purchase a light bulb. Amazingly, this two liter solar light requires nothing more than a water bottle filled with water:
The bottles function as 60-watt lights powered by 100% solar energy. Refraction is an amazing thing, if you drilled a hole in your ceiling light would drop directly through the opening in a straight line casting a shadow on the ground in the shape of the hole. By placing a bottle filled with water into the hole, the light is refracted by the water and emitted at 360 degrees like a light bulb.
This is truly a simple, beautiful piece of ingenuity. What makes it even more appealing is that it gives folks an opportunity to use something that would ordinarily go straight to the trash.
Do you want cheap solar lighting for your home? Then look no further than a bottle of water!
It strikes me that there is a LOT children can do to promote this idea by informing people in their family and community. They could also become active in collecting the plastic bottles and finding out those families who would benefit from the technology.