Question: What do tonic water and highlighter pens have in common?
Hypothesis: I don't think they have anything in common since highlighters are writing instruments and tonic water is a drink.
1. Carefully break open a highlighter pen, remove the felt and soak it in a small amount of water for a few minutes.
2. While the felt is soaking, shine a black light on a bottle of Tonic Water and watch what happens!
3. Take the highlighter in water mixture to a dark place and shine a black light on it to see what happens.
1. We will need a dark place and an outlet.
The Science behind it
A black light lamp emits a UV light which is part of the electromagnetic spectrum. The electromagnetic spectrum also includes infrared, X-rays, visible light (what the human eye can see) and other types of electromagnetic radiation. A black light lamp emits a UV light that can illuminate objects and materials that contain phosphors. Phosphors are special substances that emit light when excited by radiation. The water glows because the UV light reacted with phosphors in the tonic water and highlighter dye.
We deny our hypothesis because Highlighter pens and tonic water both have phosphors that turn UV light (light we can't see) into visible light (light we can see). We didn't know about this before. That is why our water glows in the dark when we shine a black light on it.