Fluorescence

light science · glow · invisible rays · chemistry

Invisible light source.. Ultraviolet radiation is light we can't see with our eyes, but many materials absorb it and turn it into colored light we can see. The color depends on what the material is made of.

Instant on and off.. When you shine ultraviolet light on fluorescent material, it glows right away. The moment you turn off the ultraviolet light, the glow stops almost immediately, like flipping a switch.

Electrons jumping around.. Inside the material's atoms, electrons absorb the ultraviolet energy and jump to higher energy levels. When they fall back down, they release that energy as visible colored light we can see.

Color tells the story.. Different materials glow different colors because they're made of different chemicals, and each one releases energy in a special way. Neon signs, highlighters, and some minerals all fluoresce in different colors.

Different from phosphorescence.. Phosphorescence is similar but works differently, because those materials keep glowing for a while even after the ultraviolet light stops. Glow-in-the-dark stickers use phosphorescence, not fluorescence.