Under ultraviolet light, many common minerals glow in brilliant colors. On Thursday, July 11 at 6:30 pm, join us as we learn how these fluorescent minerals were discovered and what causes them to glow. At this free program, Harlan Clare, retired Plum Borough School District Science Department Chairman and current docent at the Carnegie Museum of Natural History, will explain and demonstrate what causes the minerals to glow, how fluorescence helped the United States during World War II and how it is used today in forgery prevention, advertising, mail processing and entertaining. We are sure this free program will interest an audience of all ages, and everyone attending will receive fluorescent mineral and ultraviolet detecting glow beads. You may register through the library’s website: www.northlandlibrary.org or by calling the adult services desk at 412-366-8100, extension 113.