10 Everyday Items You Didn’t Know Glow Under Black Light
Black lights reveal a hidden fluorescent world — many everyday items around your home hide glowing secrets.
Flip off the lights, switch on a UV lamp, and explore the glow.
1. Tonic Water
The bitter-tasting drink we know as tonic water contains quinine — a molecule that fluoresces under ultraviolet (UV) light. Under a black light, the tonic water glows an electric blue, turning a regular drink into something otherworldly.
Try this: Pour tonic water into a clear glass (or even freeze it into ice cubes). In a dark room, shine a UV light and watch the liquid — and even ice — glow like a neon potion.
2. Laundry Detergent & Fresh White Clothes
Many detergents incorporate so-called optical brighteners (phosphors) — chemicals that absorb UV light and re-emit visible light, usually bluish-white. That’s why freshly washed white T-shirts or linens often glow under a black light.
Real-world fact: This fluorescence isn’t just party trick — similar fluorescence helps forensic investigators reveal traces or stains that are invisible under normal light.
3. Fluorescent Highlighters & Markers
Many highlighter pens contain fluorescent dyes that are designed to glow vividly under UV — yellow, green, pink or orange ink all pick up UV and glow intensely.
Fun experiment: Remove the ink cartridge, drop it into water (or paper), shine a black light, and watch it glow like neon liquid or glowing graffiti — an easy, cheap science activity.
4. Some Vitamins & Supplements (like B-Vitamins)
Certain vitamins (especially some B-vitamins) and supplements fluoresce under UV light. When dissolved (or under specific conditions), they can emit visible glow.
Important safety note: This is meant as a visual demonstration only — don’t consume experimental mixtures unless you’re following safe procedures.
5. Petroleum Jelly (and Similar Hydrocarbons)
Products like petroleum jelly can fluoresce under UV light — the hydrocarbons in these materials absorb UV and re-emit visible light, often a soft bluish or greenish glow.
DIY fun: Use a small amount on a non-porous surface (glass, plastic) and shine a UV lamp — you’ll see a subtle but clear glow. Great for Halloween effects or artistic projects.
6. Honey (Natural, Raw Varieties)
Some natural honeys contain compounds (enzymes, pollen traces, etc.) that fluoresce under UV. When placed under a black light, honey may glow faint greenish or yellowish, depending on composition.
Try it: Spoon a bit of raw honey onto a white plate or glass, turn off the lights, shine a UV light — the glow is subtle but visible in a dark environment.
7. Olive Oil (Especially Extra-Virgin / High-Quality Oils)
High-quality olive oil — due to traces of chlorophyll and other naturally occurring compounds — can show slight fluorescence under UV light, sometimes a subtle greenish glow.
It’s not a dramatic glow — but noticeable when viewed in a dark room with a black light, especially if the oil is in a clear glass container.
8. White Paper (Office Paper / Printer Paper)
Many kinds of paper contain fluorescent brightening agents (optical brighteners) — chemicals added during manufacturing to make paper appear whiter under normal light. Under black light, these agents glow, making plain white paper emit a cool blue-ish glow.
Test it: Use a black light in a dark room and hold various papers side-by-side; premium paper often glows more strongly than cheap paper — a fun “paper comparison test.”
9. Banana Peels & Some Plant Materials
As bananas ripen, their peels — and in some cases other plant-based materials — may develop fluorescent compounds. Under UV light, you may notice subtle glowing patterns on the peel.
While the glow tends to be faint compared to tonic water or fluorescent inks, it’s a curious reminder of the chemistry hidden in common fruit and plants.
10. Fluorescent Minerals, Vintage Glass & Certain Plastics
Items such as fluorescent minerals, certain vintage “uranium” or “vaseline” glassware, and some plastics contain compounds that fluoresce under UV light. Exposed to a black light, they can glow in vivid blues, greens, or even other colors depending on their composition.
Great for collectors: If you have old glassware, mineral samples, or acrylic decor — shine a UV light on them in a dark room and you might uncover hidden glowing beauty.
Want even **more surprising glow-in-the-dark discoveries**? Drop a comment or send me ideas — I’ll expand this list 👇
