Why is a rainbow in an arch? Does it have something to do with an equal distance from me to the raindrops and if so, is the arc really a parabola? — MM, Seattle, WA
A rainbow is truly circular, not parabolic. Passing through the exact center of that circle is the line that runs between the sun and your head. Each colored arc of the rainbow is located at a particular angle away from this line—the red arc is farther from the line than the violet arc is.