How to Make Glowing Water : Science Experiment

Lets learn - How to make Glowing Water ? In this experiment we tried to make glowing water using 3 different ways (Tonic water, Fluorescent paint & Highlighter Pen). Try it today.

In this article, lets discuss about ‘Glowing Water Science Experiment’.

Wondering how the things glow in the dark! Believe me, it can be a so much fun and at the same time kids learn something about the light science.

The main ingredient behind the glowing water is tonic water containing quinine compound.

Yes, tonic water does not look any strange when you see under normal light. But it does magic under black light. Let us learn the magic of tonic water further.

In this experiment, we are going to prepare and observe or analyse four different types of water filled in glass jars.

One glass jar is filled with normal tap water, one jar filled with tonic water, one jar filled with fluorescent pain, and the final jar is filled with the highlighter ink. Let’s find out which type of water glows.

I asked my kids to tell if they have any predictions.

My younger kid said all the four glass jar glow in the dark. Loll! No surprise for me to expect such funny answers from her.

But with the knowledge of previous glowing science experiment, my elder daughter gave me the answer i.e. ‘tonic water’. Now it’s time to appreciate my elder daughter. Hahaha! Reflects Mumma’s love!

Glowing Water Science Experiment

Supplies Needed

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Glowing Water Experiment - Things Required

As we are using a highlighter ink, we need to extract highlighter ink from the highlighter pen. Open the highlighter pen by prying off the very top piece of the pen or by screwing the pen.

Take required amount of water in a glass beaker and then soak the felt inside the water. Keep in mind that lesser the water, the higher the concentration.


Follow the below mentioned steps to experience the magic does by our liquids under black light.

How to make glowing water - 3 ways (Tonic Water, Highlighter pen, Fluorescent pen)

Step-1: Fill the glass 1 with normal tap water.

Step-2: Prepare another glass labelled 2 for the experiment. To do so, fill the glass with tonic water.

Step-3: Now take the third glass and fill with the normal water. Here we are using fluorescent paint to mix it with the water. Set aside.

Step-4: Then prepare the glass 4 for the experiment by filling water and with highlighter ink. We have already discussed how to make the highlighter ink in ‘preparations’ heading.

Now all the glasses are ready to glow in the dark room.

Time to Glow

Glowing Water Experiment under Black Light

My daughters helped me to place all the four glasses filled with different liquids in the dark room which we have set up for the experiment.

Now I asked my daughters to set the black light about 12 inches away from the liquids in the glasses.

And see the magic by the black light in the dark room.

My kids are amazed by the glow of the water with a small suspense in their faces. Here are the results you can see from the picture.

How does the glowing water science experiment works and the science behind it!!

As we see in the picture, glass 1 with normal tap water does not glow under black light.

Whereas glass 2 with tonic water glows amazingly under black light. The ultra violet rays being emitted by the black light makes the tonic water glow.

But how? Tonic water contains a chemical compound called quinine. Quinine under black light turns the invisible ultra violet rays to visible rays making the water glow in the dark.

That is the reason black lights are used in forensic labs, photography, artistic performances, antiques, authentication of bank notes etc.

The electromagnetic rays being emitted by the black light make the things that contain phosphors glow in the dark.

Phosphors are such compounds that gets excited and emit light under radiation. This phenomenon is called luminescence.

The chemical compound quinine in tonic water contains phosphors which is why the tonic water glows under black light.

Coming to the experiment glass filled with highlighter ink, we see a bright colored glow after it is exposed to black light.

The highlighter ink contains phosphors which gets reacted with the UV-A light spectrum coming from the black light. Thus making the water glow by emitting visible light.

Next moving on to the glass filled with water and fluorescent paint. The reason for the glowing water applies here.

The phosphors in the fluorescent paint makes the water glow under black light.

What is Black Light?

Let’s learn – What is Black Light? It sounds contradictory. Black light is a small light that emits light from the range of ultra violet-A light spectrum.

It is actually invisible to human eye and is purple in color.

Since the light emitted from the black light is outside the range of human vision, a room appears dark when illuminated with a black light. It causes every day or daily life objects glow in the dark.

Safety Measures

  • The black light that we used made for domestic use and not necessarily can cause harm to kids. However, please be wary of using black light with kids. The light may cause irritation to sensitive skin.
  • Do not let kids to drink/taste any of the liquids we are experimenting with.
  • When handling the tonic water, please read the safety precautions listed on the container.

Hope you enjoyed the experiment!! Performing the experiment in the dark room is even more exciting for the kids and hope your kids also enjoy this experiment. Give it a try.  

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