Inventor of No-Electricity Refrigerator Wins Rolex Award

Mohammed Bah Abba of Nigeria won a Rolex award for his pot-in-pot refrigerator. It consists of a smaller clay pot inside a larger clay pot. The gap is filled with damp sand. As the water evaporates, the inner pot cools. Food that used to spoil in a few days now stays fresh for weeks. Second-order effects are already being noticed — for one thing, girls who had to skip school to sell food at markets can now attend classes