Glowing Water Science Experiment – Fluorescence
This simple glowing water science experiment will help teach your children about light waves and fluorescence.
It’s a lot of fun for children to perform!
They will be mesmerized by the glowing water and the use of darkness to perform the reveal really adds to the ambience of the overall results. The glowing light experiment can be accomplished in a variety of ways but for ease and safety considerations we will concentrate on my two favorite methods.
What Is Black Light?
For this experiment, we will need to use a Black Light. Sounds contradictory I know, but a black light is simply a small light or handheld torch, that emits light from the Ultra Violet A (UVA) spectrum.
A Black Light can be purchased online or via your local hobby or hardware store. The cost is low and is a very useful item to have around the home. Not only is it an essential part of a home scientists arsenal but it is very handy when checking for stains on household carpets, floors, and stairs.
Equipment Required For Our Experiment
For our experiments, we will need the following items.
- A Black Light
- 3 Small Glasses
- A Jug Of Water
- 3 Highlighter Pens (Different Colors)
- A Dark Room to show the results
Let’s Get Started!
Firstly we need to extract the ink filled felt from each of the highlighter pens. They can be a bit difficult to remove so in the interests of safety, I would suggest that the adult takes care of this task.
The felt can normally be removed by twisting the tip of the highlighter pen away from the main body. In some models, the end of the pen can be lifted off by levering it away with a small knife. If both of these methods yield no results, then take a sharp knife like a box cutter and carefully push the knife through the body of the pen. When the knife is inside, carefully pull the knife along the body of the highlighter to split the case.
Put the felts from the three pens aside, ready to be used during the experiment.
Creating A Glowing Solution
Put a small amount of water into each of the 3 small glasses and place each of the highlighters felts into each glass. The amount of water in each glass doesn’t need to be specific but it is a good idea to put just enough water to cover the felt in each glass.
If you put too much water in ink from the felt will take longer to be absorbed into the water and the ink will be diluted by the water. The result will be a weaker solution and therefore a less spectacular glow.
Leave the felts in the water for a few minutes to allow the ink to dissolve. You will notice that the colored ink start to make the water a deeper color.
After a few minutes remove the felt from the water with the tweezers and discard the ink felts.
Time To Glow
Place the three glasses in your darkened room and set the Black Light about 12 inches away from the glasses. Gather the audience around the glasses and switch of the Black Light.
When the suspense has built up to a breaking point, switch off the room light and watch the expression on your children faces. They will be amazed by the glow of the water!
But Why Does The Water Glow?
The ink from the highlighter pens contains chemical compounds that are fluorescent. Yellow and green highlighter pens contain a chemical call Pyranine which is highly soluble in water.
Fluorescent chemicals have an interesting characteristic, which allows them to absorb energy from Ultraviolet radiation (invisible to humans) and then radiate that light energy at a longer wavelength. The longer wavelength is part of the light spectrum that is visible to humans.
Because the ultraviolet light cannot be seen in our experiment, the water containing the fluorescent chemicals looks as though it is glowing on its own.
Under everyday lighting conditions, the visible light reflected by the ink is added to the light energy converted by the fluorescent material. The highlighter ink is therefore physically brighter than normal ink.
Fluorescent chemicals and compounds are all around us. From obvious uses, in highlighter pens, high visibility jackets and road safety signs to an additive in washing powders and soap,
This is how they make your whites, whiter than white! If you look at dark clothing in the darkened room with your black light, you will likely notice tiny fluorescent flecks.
Simple Alternative Experiment – What A Tonic!
If you don’t want to go to the trouble of extracting the felt from highlighter pens, there is a very simple alternative experiment that allows you to show the results of fluoresces without the mess.
Simply take a bottle of Tonic Water and place it in the darkened room with the Black Light in proximity. When the room lights are turned off you will notice that the Tonic Water glows with a slightly bluish color.
The fluorescent nature of the Tonic Water is due to the addition of Quinine as a flavoring. Quinine is compound that when added to Tonic Water to give it its distinctive bitter taste.
Is Light Always Visible?
A simple experiment like the Glowing Water Science Experiment is a fantastic way to help you explain a complex scientific theory in an easy to understand, visual way. The hands-on nature of this experiment make, it an enjoyable experience for children and parents alike, by bringing science to the home.
We learned that light has a wide spectrum and not all of that spectrum is visible to humans. In addition, we were able to understand that light waves can be absorbed by fluorescent materials and emitted as visible light, thereby physically making the material much brighter.
What Do You Think of This Experiment?
At bestscienceexperimentsforkids.com, I endeavour to help adults and their children to get hands-on with science experiments. The aim is always to strike a balance between simple, result driven experimentation and the need to explain the result in an easy to understand way.
I really hope that you enjoy these experiment with children!
If you have any suggestions, feedback or questions, I would be more than happy to take the time to reply to your comments.