Halloween is one of my favourite holidays, and a great time to incorporate weird science into normal things - like Jello! Ghoulish Glowing Jello is one of my favourite things to serve to friends at Halloween because it is easy to make, it always gets a great reaction, and it demonstrates some pretty cool science!

You make glowing Jello the same way you would make regular Jello, except you substitute tonic water for regular tap water. The key to glowing Jello is an ingredient found in tonic water called quinine.

So why does this happen?

Quinine is a highly fluorescent substance, and when it absorbs the energy in ultraviolet light, the electrons in the quinine get very excited. Too excited! The electrons can't handle that much energy, so they electrons have to release some of it. The energy is released in the form of photons or visible light! So that's why our Jello gives off a creepy glow.

If you want to make your own Ghoulish Glowing Jello, you will need:

-A package of Jello (any flavour, but I find that lime green gives off a nice ghoulish glow)

-Tonic water

-Small transparent cups or glass jars

-Black/Ultraviolet fluorescent lightbulb (these are available at most Halloween stores or places where they sell Halloween décor and can cost about $4-$6. Make sure it’s an ultraviolet light bulb, and not simply a coloured bulb.)

Optional: Gummi worms and insects or other creepy candies.

Step One:

Make the Jello according to package directions, using 1 cup of boiling tap water and 1 cup of cold tonic water.

*Note- The tonic water can give the Jello a bitter taste. It helps to add ½ cup of sugar to the Jello powder before adding the boiling water. Make sure all the powder and sugar are dissolved before adding the cold tonic water.

Step Two:

Pour Jello mixture into small cups or glass jars and chill in fridge for a few hours.

Step Three:

Test!

Take one of the Jello cups out of the fridge and test it in a dark room, under the black light. You should see a ghoulish glow being emitted from your Halloween dessert.

*Note- At this stage, you can also add some creepy gummies to the Jello. Gummi worms or insects are a great choice for this creepy dessert.

Step Four:

Enjoy!

It’s best to serve this dish in a dark room with just the black light glowing. It makes for a fun eating experience.

Step Five:

Science!

Don’t forget to share the why behind this glowing gelatinous goo. Quinine in the tonic water absorbs ultraviolet light and re-emits it as visible light.

Happy Halloween from TELUS World of Science Edmonton!