As we flip a switch to light up a room or use our cell phone flashlight to find our keys in the dark, it’s easy to take for granted how lucky we are. In many developing countries throughout the world, the people still rely on kerosene to light their way in the dark, which can be very dangerous and cost up to 20% of a person’s income. Looking to address this problem in the most efficient way possible, a team of engineers from the UK have designed an amazing light that runs on gravity and the weight of rocks or sand. As of now, the cost of each light is $10, which would pay for itself in 3 months of not using kerosene, but with further R&D the team thinks they could get the cost down to $5 each. [Read more...]