While hauling out the basement, I discovered some packages of UV reactive beads leftover from several summers ago. The kids whipped up some magic bracelets that go from clear to color in sunlight - the more intense the sun, the more intense the colors.
Matthew kept running in and out of the house, counting to see how long it took to change from clear to colors and back to clear again.
I finally had to call in reinforcements (aka, biggest sister) to corral him for a bit.
