During our Inter-group Exchange last Saturday a rainbow appeared and one girl asked me what causes them. Different girls spouted some untrue reasons and I laughed initially because I thought they were all joking around. But then I realized--they actually had no idea what causes a rainbow! And when I explained, they laughed at me, thinking it was another hocus-pocus explanation like the ones they had just offered up. So this is me trying to explain the science behind light hitting water. I think a few of them still don't believe me.