After successfully getting the lemon battery to work, you find new batteries in the depths of a drawer. Use one of these batteries to light up a small UV diode and look for the next hidden clue.

Materials needed:

  • UV LED diode
  • Batteries and adapter
  • Electrical cables and possible clamps
  • UV protection glasses or sunglasses


Execution of experiment:

  1. Put on the UV protection glasses or sunglasses.
  2. Install the batteries in the adapter.
  3. Connect the LED diode to the battery using the clamps (and cables if necessary). Make sure you connect the diode the right way around.
  4. And now go in search of clues! Look for the next clue with the UV LED diode. 



Some traces are invisible to the human eye. Under UV light, however, they may start to glow. Maybe you will find the next clue for the code!


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