======Black Light Fluorescence======


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**Alternative titles:** UV-Induced Glow
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====Summary====                   
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====Procedure====  
  - Darken the room and place sample items (white paper, petroleum jelly, tonic water or club soda, assorted vitamins, white vinegar) on a tabletop.
  - Turn on a UV flashlight and illuminate each item, noting any color changes or glow.
  - Crush small amounts of vitamins (e.g., riboflavin, thiamine, niacin, B12) in water to make test solutions; observe under UV.
  - Mix a small amount of vitamin solution with white vinegar and check again under UV to see if the glow or color changes.
  - Compare additional household items known to fluoresce (e.g., detergent-brightened fabrics, highlighter ink, some currency security features).



====Links==== 
How Fluorescence Works - The Science - NurdRage: 
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Chemistry | Fluorescent Experiment | DIY Home Experiment | Arts & Crafts | Science For Kids - Big Bang Academy Kids: 
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====Variations====
  * Compare wavelengths: test a 365 nm “true UV” flashlight versus a 395–405 nm violet LED and note brightness differences.
  * Make fluorescence art: draw on paper with petroleum jelly or highlighter, then reveal under UV.
  * Test natural sources: tonic water (quinine), vitamin B2 (riboflavin), and chlorophyll extract (spinach in alcohol) for distinct colors.
  * Contrast fluorescence vs phosphorescence using glow-in-the-dark plastic to discuss immediate vs delayed emission.



====Safety Precautions====
  * Use only UVA/near-UV black lights intended for consumer use; avoid UV-C sources.
  * Do not stare into the beam; limit direct eye and skin exposure. Consider UV-blocking glasses if sensitive.
  * Handle vinegar and crushed vitamins carefully; avoid ingestion and contact with eyes. Label all mixtures and dispose properly.
  * Protect surfaces and clothing from staining (highlighters, dyes). Wash hands after the activity.
  * Keep small items and powders away from young children; supervise closely.




====Questions to Consider====
  * Which items glowed most brightly, and what do they have in common? (They contain phosphors such as optical brighteners, quinine, or riboflavin that absorb UV and emit visible light.)
  * Why does tonic water appear blue-white under UV? (Quinine fluoresces strongly in the blue.)
  * Did mixing vinegar with certain vitamins change the glow? (Acidity can affect molecular form and fluorescence efficiency for some vitamins, notably B12 and riboflavin.)
  * How is fluorescence different from phosphorescence? (Fluorescence stops almost immediately when the UV is removed; phosphorescence continues after excitation.)
  * Where do we see fluorescence in everyday life? (Laundry brighteners, security features on money and IDs, forensic dyes, and some marine organisms.)