Highlighters have a number of uses, from helping acknowledge important text to acting as brightly-colored markers in our favorite coloring book. Around Halloween, though, we’ve found an entirely different use for them. With the Black Light Secret Message experiment, you’ll see that certain highlighters aren’t just brightly-colored – they’re actually fluorescent and glow underneath a black light! The secret messages and floating images you’ll create with this experiment are sure to create screams of joy and shrieks of excitement.