Gravity Brings Light To The World (video)
London based designers Martin Riddiford and Jim Reeves have created what they are calling the GravityLight, an LED lamp that runs off of nothing but gravity. The purpose of the lamp is to provide people in third world countries with an alternative to kerosene lamps which cause burns and lung ailments to millions of people too poor to afford any other source of light.
The lamp is as simple as it is inexpensive. A cable hangs from a gear mechanism holding onto a plastic bag filled with dirt or rocks. The energy created by gravity pulling the bag downwards is enough to power an LED bulb for up to half an hour.
The two note on their page that over a billion and a half people in the world today have no access to a reliable electricity source. When it gets dark, their only light source comes through burning wood, peat, or other biomass materials – the most popular by far, is kerosene. They also note that the World Bank has recently estimated that up to three quarters of a billion women and children regularly inhale smoke from kerosene lanterns, which is they say, equivalent to smoking two packs of cigarettes a day – a situation that leads quite naturally to very high lung cancer rates.