SAN FRANCISCO (KGO) -- A strobe light and a giant phosphorescent screen offer endless posing possibilities in the popular Exploratorium exhibit, "Shadow Box."
Inside the Shadow Box, visitors can create unique shadow art through the process of phosphorescence.
"What's happening is a bright light is flashing on this wall and the wall starts to glow," explained Desiré Whitmore. "But if we block the light, like we did with our bodies, then you have a shadow there, hence Shadow Box."
The shadow-catching phosphorescent material on the wall of the exhibit is the same as you've probably seen in various "glow-in-the-dark" products. Energy from incoming light gets absorbed in this material to excite electrons to a higher energy state. As these electrons gradually relax, they release their energy as a visible glow.
Phosphorescent materials glow for several seconds or more, but fluorescent materials only glow while the light is on them. Once the light that is exciting the material goes away, so does the fluorescent glow.
Fluorescence is very common, and you may have seen it if you have ever seen a black light being used to make things glow. A black light is actually ultraviolet (UV) light, which has even more energy than blue light. This means that UV light can even make some blue objects glow.
Watch the video above to join Drew as he explores light, shadow, and glow!
For more exhibit information and to plan your visit, go here.