For New Lamps, An Unlikely Energy Source: Gravity

As long as you reset a weight every 30 minutes, you can have a continuous, battery-free light source. GravityLight: lighting for the developing countries from T4 on Vimeo. Kerosene lamps used in off-grid, rural areas are a major problem. They're bad for people's health and the environment's. One startup's solution is to tap another, greener resource, something we all have in abundance: gravity. The invention, GravityLight, does exactly what the name suggests: It keeps a light going through the p...