FOUR TYPES OF RAINBOWS
We are used to seeing rainbows on rainy days, but the phenomenon occurs anywhere in the presence of water drops and light. Depending on the size of the drops, the light source, and the observer’s position, the rainbow might seem different, although the pr
MOONBOW: Rainbows are most frequently associated with sunlight, but bright moonlight can also cause rainbows. However, the colours are weak or nonexistent, as our colour vision is poor at night. The moonbow will hence very often seem whitish.
FOG BOW: Fog consists of water drops that are so small that individual colours will be dispersed and mixed to such an extent that a wide, whitish rainbow results. So, this rainbow will not always be associated with ordinary rainbows.
SUPERNUMERARY BOWS: On the inside of the primary rainbow, you can very rarely observe a series of extra arcs that do not form in the same way as the rainbow itself. These arcs are due to the fact that the light beams in a raindrop can intensify or weaken each other (interference), and to make them visible, it is necessary that the raindrops be very similar in size.
RAINBOWS IN WATERFALLS: A rainbow is often produced in the drops from the turbulent water volumes of a waterfall. There, you might see the entire circular rainbow, if you are above the waterfall, looking down at the water drops.