Physics Photo of the Week

Warren Wilson College

October 1, 2004

Ligntning, by Dan Sockwell
Twin Lightning

I took this picture on July 16, 2004 at 1:32 a.m. at Camp Albemarle, a small camp where I work located on the Bogue Sound on the coast of North Carolina.  It was a 25 second exposure at f/4.5.  I was fortunate that night because the storm was across the sound travelling parallel to the land, allowing me to take several hours of pictures.  Daniel Sockwell - Warren Wilson Student.




Close-up of part of the lightning photograph.

Besides the beauty of these remarkable photographs, there is considerable physics displayed.  Notice the ripples in the water - in 25 seconds, the ripples would be all smeared out due to the motion of the water waves.  But Dan made this photograph at night where the only light was the "flash" of the lightning.  The brief flash of the lightning created the stop-action of the waves on the water.  Also notice the erratic curves and bends of the main lightning streaks.  The lightning bolt consists of a series of segments about 3-4 meters in length.  Each segment creates a single explosion sound - a single boom in the thunder.  Because lightning is very extensive and consists of many branches, and the different parts of the stroke are different distances from the observer, each "boom" arrives at the observer at a different time.  The result of all the "boomlets" arriving at different times creates the extensive rumble of thunder.  Donald F. Collins


Physics Photo of the Week is published weekly during the academic year on Fridays by the Warren Wilson College Physics Department.  These photos feature an interesting phenomena in the world around us.  Students, faculty, and others are invited to submit digital (or film) photographs for publication and explanation.  Atmospheric phenomena are especially welcome.  Please send any photos to dcollins@warren-wilson.edu.

Click here to see all Physics Photo of the Week for 2004.