Transkript (en)

This is a refrigerator that works without electricity. First, wet sand is packed between two clay pots. Because the clay is porous, a small amount of water slowly passes through the outer wall and begins to evaporate. To change from liquid into vapor, the water absorbs heat from the inner pot, causing its temperature to drop. A damp cloth placed over the top helps keep the cool air inside. This simple process, known as evaporative cooling, keeps fruits and vegetables fresh for longer, making it especially useful in hot, dry regions where electricity may be limited.