Invisible Highlighter Ink Under UV
Some marks glow intensely.
Teaching & key ideas
What you do: Compare marks under room light and UV.
What students see: Some marks glow intensely.
Why it works: Fluorescent dyes absorb UV and emit visible light.
Question to ask: Why is the glow brighter than the paper around it?
Lesson flow
Predict → demonstrate → observe → briefly explain → ask: Why is the glow brighter than the paper around it?