No, not every material is fluorescent. Fluorescence occurs when ultraviolet rays that we can't see hit a material that absorbes it and radiates longer wavelength light that we can see. This is why fluorescent materials seem to glow under black light; we see little light coming out of the lamp since it is mostly UV but the fluorescent material changes it to light we can see. White materials that are not fluorescent will remain dark. Ever wonder what is in laundry detergent that promises whighter-than-white whites? It is a chemical that causes our clothes to fluoresce and look brighter. While many biolgical chemicals fluoresce I do not know off the top of my head if lactose is one of them and a quick web search hasn't provided me an answer.
There are a lot of everyday materials that fluoresce, or glow, when placed under a black light. A black light gives off highly energetic ultraviolet light. You can't see this part of the spectrum, which is how 'black lights' got their name. Fluorescent substances absorb the ultraviolet light and then re-emit it almost instantaneously. Some energy gets lost in the process, so the emitted light has a longer wavelength than the absorbed radiation, which makes this light visible and causes the material to appear to 'glow'. Fluorescent molecules tend to have rigid structures and delocalized electrons. Examples of common materials that contain fluorescent molecules include
oohh i thought tht it could glow !! as lactose is found in milk and milk is white :P
is itbad if i hav random white spots on my skin under a black light??
yeah ! basically anything that is white glows with black light! :)