Over the summer I've been making these bracelets for DJ's friends, as birthday gifts and "just because" gifts, because they are fun and useful. The beads I got from Steve Spangler Science -- they're called "Solar Changing UV Beads." When they're in the sun they change color. It's fun for kids to experiment with them and a good way for parents to find out when to reapply sunscreen -- if you have the children wear the bracelets while applying sunscreen, the beads will remain white until the sunblock wears off. When they change color, it's time to reapply!