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SMARTR - Math/Science Virtual Learning Experiences for Youth
Posted by Kim Lightle on September 24, 2013 at 1:30pm
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Posted by Kim Lightle on December 11, 2012 at 2:10pm
Pictured at left is a charged 4 inch x 12 inch x ½ inch specimen of acrylic plastic being discharged to form a "captured lightning" Lichtenberg figure. A neutral density filter was used to prevent the camera from being overexposed by the brilliant flash. A particle accelerator was used to charge up the interior of the specimen to over 1.7 million volts. By poking the edge with a grounded point, the trapped charge was suddenly released. Although the electrical discharge lasts for less than 250 billionths of a second, the miniature lightning-like discharges leave behind permanent branching chains of tubes and fractures inside the acrylic, effectively forming a "fossil" of the discharge. The fractal pattern is similar to many other branching forms in nature, such as animal circulatory systems, branching tree limbs, and rivers and their tributaries.
Image credit: Bert Hickman, Stoneridge Engineering