Fire-breathing at a carnival sideshow?

• Position: NEWS & TRENDS - Schlieren photography - Brief article

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FIRE-BREATHING AT A CARNIVAL SIDESHOW? No, this photo captures something far more elusive: an ordinary cough. Gary Settles, an engineering professor at Penn State University, uses a technique called schlieren photography, which "takes an invisible phenomenon and turns it into a visible picture," he says. Often used in aeronautical, engineering to photograph air flow, the process involves a small, bright light source, precisely placed...