East River Reflections

The glassy undulating surface of water is a non-stop, delightful, and hypnotic display. The mosaic of shapes and colors (blues, greens, blacks, whites, browns, and sometimes red and yellow) result from the physical/geometric optics and chemical physics of the water and surrounding environment. The color of water is determined by upwelling light underneath the surface, reflected skylight, and light scattered by the intervening air, collectively involving absorption, refraction, reflection and scattering. Its appearance is influenced by sunlight, clouds, sediment, bubbles, depth, bottom vegetation, the viewing angle and whether the water is calm or ruffled. Water's  “intrinsically” blue color arises from internuclear vibrational transitions. Most or all other blue substances owe their color to electronic transitions. In his delightful book Clouds in a Glass of Beer, Dr Craig F. Bohren writes that “The world was not designed for the convenience of those who frame multiple choice questions.” Undoubtedly true, unless there are numerous choices including “All of the Above.”

—Photo and caption courtesy of Manfred Hauben, MD, MPH