Cool!

 

This is Mohammed Bah Abba's Pot-in-pot invention. In northern Nigeria, where Mohammed is from, over 90% of the villages have no electricity. His invention, for which he won a Rolex Award (and $100,000), is a refrigerator that runs without electricity.


Here's how it works. You take a smaller pot and put it inside a larger pot. Fill the space in between them with wet sand, and cover the top with a wet cloth. When the water evaporates, it pulls the heat out with it, making the inside cold. It's a natural, cheap, easy-to-make refrigerator. So, instead of perishable foods rotting after only three days, they can last up to three weeks. Obviously, this has the potential to change their lives. And it already has -- there are more girls attending school, for example, as their families no longer need them to sell food in the market.
The idea has been around for millenia but no-one had thought to apply it in the modern world. I wonder how many more simple ideas are just waiting to be re-discovered?