Colorful Cocoa

June 29, 2013

KakaoA 012 - m aus (2)

Photographer: Hans Juergen Heyen
Summary Authors: Hans Juergen Heyen; Jim Foster

On a Colorful Cocoa BOTTOMpleasant spring day in Meerbusch, Germany, while in my garden enjoying the midday Sun I noticed these colorful bubbles on the surface of a cup of hot cocoa I was sipping. If the film that forms a bubble is sufficiently thin, diffraction of sunlight (interference) will cause iridescent colors to appear. The pastel colors that result are due to variations in the thickness of the bubble’s film and to the angle of the observer’s line of sight. A drop of oil or gasoline in a water puddle produces a similar effect. The presence of lipids or oils in the cocoa likely contributes very little to these colorful patterns. Photo taken on April 28, 2013.

Photo Details: Both photos - Camera: Panasonic DMC-FZ100; Focal Length: 4.5mm (35mm equivalent: 26mm); Aperture: f/4.0; Exposure Time: 0.0010 s (1/1000); ISO equiv: 100; Software: Microsoft Windows Photo Gallery 6.0.6001.18000.