Sea-foam Gems

May 31, 2011

Seafoam1 
Photographer: Bill Oterson; Bill’s Website
Summary Author: Bill Oterson; Jim Foster

While walking a local beach earlier this month on Long Island, New York, I was amazed by these colorful sea-foam “jewels.” The structure of sea foam is related to the structure of clouds but where clouds are tiny droplets surrounded by air, foam is composed of air bubbles surrounded by water. Like clouds, sea-foam appears white. However, coloration can occur if a thin interference film is present on the bubbles, which acts to deflect sunlight. The colors that are viewed result from variations in the thickness of the film and the angle of the observer’s line of sight with the bubbles. These colors, shown here on a piling, lasted until the bubbles were jostled by the rising tide. Note my silhouetted image reflected in the bubbles. Photo taken about 10:00 a.m. May 15 in Great South Bay, Sayville, Long Island, New York.

Photo details: Camera Maker: Canon; Camera Model: Canon EOS 5D Mark II; Lens: EF70-200mm f/2.8L IS USM; Focal Length: 175mm; Focus Distance: 1.42m; Aperture: f/2.8; Exposure Time: 0.0005 s (1/2000); ISO equiv: 500; Exposure Bias: none; Metering Mode: Center Weight; Exposure: Manual; Exposure Mode: Manual; White Balance: Manual; Flash Fired: No (enforced); Orientation: Normal; Color Space: ProPhoto RGB; photo; colors slightly enhanced.