tonic water with plastic eye balls glowing under black light
Glow ahead and make this simple and cool experiment at home!

Glow in the dark water

Use tonic water and a black light to make glow in the dark water!

How it works:

Tonic water was originally invented in Africa and South Asia by the British as a prophylactic treatment for malaria.  It contained carbonated water and quinine, with the quinine being the ingredient that treated malaria. Quinine is made from the bark of a cinchona tree, and gives the tonic water it’s bitter taste. Today, tonic water is made in a similar way, but contains lower doses of quinine and has sweetener or fruit extract added.  The quinine is also the part that makes it glow under ultraviolet light, also known as black light.

How does it glow?

When something absorbs light energy, it gets excited.  The glow we see occurs when it returns to its unexcited state and gives off light.   This reaction can be seen in some types of rocks and minerals, chlorophyll, fish, and high-value dollars, to name a few.  (see more things here:  Objects and toys that glow-in-the-dark follow the same process.  They contain a material called, phosphor, that makes this happen.  By exposing the object to light prior to use the phosphor takes in the light energy and slowly releases it causing it to give off the light that you can see.  In tonic water, the quinine gives off a green glow in the same way.

How to make glow in the dark chlorophyll:

How to do:


  • Black light (I got mine at Home Depot)

  • Lamp

  • Tonic water

  • Clear Cup

  1. Pour tonic water into cup

  2. Turn off the lights

  3. Turn on the black light

Watch your water glow!

Book Recommendation

“Flashlight Night” This cute rhyming book by Matt Forrest Esenwine isn’t exactly Halloween themed, but I think it deserves mention anyway.  It is about 3 children that use a flashlight and their imagination. They shine the light on objects in their backyard at night and see incredible things as they go on an adventure!


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