"Sure looks like a lot of fun in there, doing all those physics experiments." http://www.flickr.com/photos/vintagehalloweencollector/ / CC BY-NC-SA 2.0 If there's one holiday that seems tailor made for the physics enthusiast (besides Pi Day), it's Halloween. You can trick out your home or Halloween party with spooky effects and decorations, courtesy of science and a few readily-available ingredients. Blacklights The light coming from these bulbs isn't black at all, but ultraviolet. We can't see ultraviolet light; instead we see a violet glow (ultraviolet light's visible neighbor on the spectrum) from the bulb, and a white glow from teeth and white shirts and socks. That's thanks to phosphor, an element that glows in the visible spectrum when excited by higher-frequency wavelengths (confusingly, this phenomenon is called fluorescence.) Laundry detergents contain phosphor to make white clothes seem brighter in sunlight, and phosphor is second only
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