"The cause is hidden; the effect is visible to all."--Ovid

Back again with this week's experiment coming from SICK Science. This week's experiment is about creating secret messages using a highlighter and a black light.
Highlighters have a number of uses, from helping acknowledge important text to acting as brightly-colored markers in our favorite coloring book. 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 for Halloween!
Here are the instructions:
Highlighters have a number of uses, from helping acknowledge important text to acting as brightly-colored markers in our favorite coloring book. 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 for Halloween!
Here are the instructions:
- Use a pen to trace the circumference of a plastic cup on a piece of white paper. Don't use thick paper like card stock or construction paper. Just pull a piece of paper out of a printer… that'll work perfectly!
- Use Sharpie highlighters to create brightly-colored designs within the circle you traced. Try using different colors when creating your design.
- Cut the traced circle out with a pair of scissors.
- Carefully poke a small hole in the bottom of the plastic cup using the scissors. Try to poke the hole as close to the center of the cup as possible.
- Apply a thin layer of glue around the edge of the circle. Make sure the glue is on the back side of the circle, away from your design, otherwise your design or message will be backwards. (Depending on what your design or message is, this could be a big deal!)
- Press the mouth of the cup onto the glue-covered edge of the paper circle. We recommend letting the glue dry before moving on to the next step, but hey… we aren't here to slow you down. (Remember to clean up any glue that squeezed out and onto the table where you're working. Happy parents make for happy scientists.)
- Now that your cup and design are attached, push the Mini Black Light's bulb into the hole you poked in the bottom of the cup.
- Are you ready for this? Turn the lights off and turn on the Mini Black Light.
- Whoa! The ink from the highlighters glows in the ultraviolet light!