michael kors black Friday sale Attached to the lamp, which is expected to retail for around $10 when it comes to market, is a bag that can hold about 20 pounds of sand or rocks and gravel which acts as the fuel when combined with gravity.The bag is build to descend under the weight of the materials which then triggers a set of gears that translate the force into power and light. It also works as a generator and can be used to charge radios and batteries.Since the GravityLight runs on available resources, once it's purchased there are no further costs to operate the lamp.According to a study published by the Guardian, in India alone 2.5 million people suffer severe burns from kerosene lamps every year and the cost can account for 20% of a household's income.GravityLight is currently raising money on Indiegogo through the middle of January. So far they have raised over $260,000, far beyond their initial goal of $55,000..Dannell Ellerbe (Miam