This morning my daughter woke up with an idea for an experiment...
A's hypothesis: If you colour a tissue with markers and wrap it around a rock, and place it in the fridge, then after some time, when you take the rock out of the fridge it will glow in the dark.
A's conclusion: It didn't work, but maybe we had to leave it in the fridge a little longer.
My little scientist then remembered how her nails glowed in the dark with her glow in the dark nailpolish.
So we painted some rocks with the nailpolish, and got the desired effect she was looking for :).... Glow Rocks.
I wasn't able to take a good picture of them glowing in the dark with my camera, but I think you get the idea :).