The quinine in tonic water shines a strange blue-white colour when lit with UV light. Explain what is happening here.

Here's what I get.

Explanation:

Quinine contains phosphors, substances that glow when they are hit with certain wavelengths of light.

The phosphors in quinine absorb UV light, which is invisible to our eyes.

Electrons in the phosphors absorb the UV energy and are excited to higher energy levels.

When the electrons drop back to lower energy levels, they emit some of this energy as a glowing blue visible light.