OK, so maybe I paid more attention in science class than some people. And I used to watch "3-2-1 Contact" on PBS as a kid, which taught me some stuff. But I'm pretty sure rainbows are caused when water droplets (rain, mist, water from a hose or sprinkler) refract sunlight, causing a prism effect.
I also vividly recall being able to create a small rainbow effect with the spray from our garden hose when I was a kid in the early 80's. And as far as I know, my parents weren't dosing me with LSD at the time.
Of course, this lady thinks that rainbows like that didn't exist 20 years ago. So obviously it must be a government conspiracy to put some goofy chemicals in our water, and stuff that's oozing up through our ground. Now that's a special kind of crazy.
And by the way, if you're dumb enough to start buying into her nutbag theories... here's how rainbows actually work: http://en.wikipedia.org/wiki/Rainbow