system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do blacklights make white stuff glow?
gpt
Ok so our eyes can only see from red to violet (red,orange,yellow,green, blue and violet). The rest, either we cannot see or we see black.
A black light produces what we call ultraviolet light. Ultra goes for what's over violet in the electromagnetic spectrum. 

What you see thanks to a black light are **phosphors**. Basically a phosphor is anything that emits **visible light** in response to some sort of radiation. So a phosphor will "convert" the energy in the UV radiation from the black light into visible light (from red to violet).

The general phenomenon is called **Luminescence**. And in this case, it's called **Fluorescence** or **Phosphorescence**.

The difference is that Fluorescence occurs so **quickly**, you can see the material glow when the light is on and stop glowing when the light is off. While Phosphorescence is **delayed**, the black light (UV) absorbed by the material can release light **seconds, minutes or even hours after exposure**.