A few degrees can make a big difference when it comes to food storage. Foods can go bad if they get too warm. But for many of the world's poor, finding a good way to keep food cool is difficult. Refrigerators are costly and they need electricity.
Yet spoiled food not only creates health risks but also economic losses. Farmers lose money when they have to throw away products that they cannot sell quickly.
But in nineteen ninety-five a teacher in northern Nigeria named Mohammed Bah Abba found a solution. He developed the "Pot-in-Pot Preservation/Cooling System." It uses two round containers made of clay. A smaller pot is placed inside a larger one.
但在1995年，尼日利亚北部一位名为默罕默德·巴·阿巴（Mohammed Bah Abba）的教师找到了一个解决办法。他发明了“罐中罐储藏/冷却系统。”该系统使用两个粘土制成的圆罐，把小罐子放到大罐子里面。
The space between the two pots is filled with wet sand. The inner pot can be filled with fruit, vegetables or drinks. A wet cloth covers the whole cooling system.
Food stored in the smaller pot is kept from spoiling through a simple evaporation process. Water in the sand between the two pots evaporates through the surface of the larger pot, where drier outside air is moving.
The evaporation process creates a drop in temperature of several degrees. This cools the inner pot and helps keep food safe from harmful bacteria. Some foods can be kept fresh this way for several weeks.
People throughout Nigeria began using the invention. And it became popular with farmers in other African countries. Mohammed Bah Abba personally financed the first five thousand pot-in-pot systems for his own community and five villages nearby.
In two thousand, the Rolex Watch Company of Switzerland honored him with the Rolex Award for Enterprise. This award recognizes people trying to develop projects aimed at improving human knowledge and well-being.
2000年，瑞士劳力士钟表公司授予他劳力士雄才伟略大奖（the Rolex Award for Enterprise）。该奖项表彰那些为提高人类知识水平、改善人类生活而努力开发项目的人们。
A committee considers projects in science and medicine, technology, exploration and discovery, the environment and cultural history. Winners receive financial assistance to help develop and extend their projects.
The awards are given every two years. The next awards will be presented in late two thousand twelve. Last year, Rolex launched the Young Laureates Program for the younger generation.