White beads turn coloured when outside! Once inside they turn white again. What causes this reaction? Ultraviolet radiation. Make yourself a bracelet made of beads to detect UV rays!
These magical beads contain photochromic pigment, which changes its color under the influence of ultraviolet radiation from the sun. They will change their color from white to pink, burgundy, orange, yellow, light blue, blue, violet and back many times. And even when it's cloudy outside!