ELI5: Explain Like I'm 5


A fluorophore is like a special chemical compound that can take in light and give off light that's different than the light it takes in. It's like a special chemical flashlight! When you shine a light on a fluorophore, it absorbs the light, and then reflects a different color of light. That's why things that have fluorophores in them look like they light up when you shine a light on them.