About the Cover

Death Valley’s Badwater Basin is the lowest point in North America. Where there was once an ancient lake, water now flows underground in porous soil. As water evaporates, it leaves behind salt and other minerals, which slowly accumulate. Instead of producing a flat crust on the surface, the minerals develop a network of narrow ridges that form polygons a few meters in diameter, as shown in the image. To learn about the convective fluid dynamics that produce the polygons, turn to the Quick Study by Cédric Beaume, Lucas Goehring, and Jana Lasser on page 62. (Photo courtesy of Lucas Goehring and Jana Lasser.)