Invisible Highlighter Ink Under UV

Some marks glow intensely. Ask students to predict what will happen. Compare marks under room light and UV. Key idea: Fluorescent dyes absorb UV and emit visible light. Ask: Why is the glow brighter than the paper around it? Safety and cleanup: Low-power UV; never shine in eyes. https://www.google.com/search?q=%22Invisible+Highlighter+Ink+Under+UV%22+science+demonstration+experiment