Ripples on Pond Created by a Butterfly

August 11, 2016

Water waves (2)

Photographer: Bertrand Kulik
Summary Authors: Bertrand Kulik; Jim Foster
The photo above shows ripples created by a butterfly alighting upon the surface of a pond in Issy-l'Evêque, Burgundy, France. In its distress to escape the water's grasp, this six-spot burnet (Zygaena filipendulae) generated periodic waves by flapping its wings. Initially more or less elliptical in shape, the waves become circular as they move further from the point source (wings). This is because, according to the Huygens-Fresnel principle, as ripples or waves propagate, though any irregularities are maintained, they spread across a larger and larger circular wave front and thus appear circular.
Photo Details: Camera Model: Canon EOS 7D;Lens: EF100-400mm f/4.5-5.6L IS USM; Focal Length: 400.0mm; Aperture: ƒ/5.6; Exposure Time: 0.0025 s (1/400); ISO equiv: 800; Software: Adobe Photoshop CC 2015 (Windows).