When Lightning Paints the Rain
Manan Ladumor
Award: Top 100
School: vanguard high school
Teacher: christina davis
Category: Natural
Photo #21212
When Lightning Paints the Rain
Through some luck and effort, I managed to capture this photo that illustrates a specific optical phenomenon. It was taken at night, in near-complete darkness, during heavy rain and lightning. The brightness of the scene is entirely due to a lightning flash.
As it was raining at the time, a few raindrops are visible as parallel motion streaks in the top-left corner. Some portions of these streaks are whitish-grey, while others appear colorful. The colorful pattern is due to dispersion of white light. Dispersion occurs when white light, which contains all wavelengths of visible light, is split into its constituent colors. As the wavelengths in white light travel at slightly different speeds through a medium, they refract by different amounts when entering and leaving that medium, creating visible spectra.
In the case of the photo, the lightning flash provided a brief but intense burst of white light. This white light struck the droplets, which acted as tiny prisms, dispersing the light into the spectra visible in the streaks. The geometry between the lightning flash, the raindrops, and the camera also mattered as the streaks only appeared colorful when their relative positions were just right. Since the drops were in motion, only those passing through the correct alignments produced the visible spectra. Additionally, the two colorful streaks appear different from one another because the droplets had slightly different positions relative to the lightning and the camera.
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