A clever way to get light into homes in poorer countries
This amazing video (not available now) shows how to turn off electric lights in poorer countries by simply taking a plastic water bottle, fill it with water and insert it into the corrugated roof overhead. The inventor even determined that it works best if you put a plastic film container over the cap to keep it from drying out.
This invention is clearly effective and reduces the cost of electricity. The savings is huge because of the income to savings ratio. Also, as I well know, natural daylight provides better health and attitude.