The photo above is stunning. Marissa Reyes captured the power of Wednesday’s storm in Fulshear.
When I visit schools, one of the topics I love to talk about is how rainbows form. Since so many people spotted them after Wednesday’s storms, I thought I’d share that same explanation with you.
First, sunshine and rain must be present. There’s an easy trick to finding a rainbow: Put the sun behind you and the rain in front of you. From your perspective, the arc forms 42° degrees from the path of sunlight. That angle is why rainbows always appear in the same general part of the sky relative to the Sun and why they form that familiar arc shape.
And as Wednesday showed us, when the timing is right after a storm, the result can be spectacular.
When sunlight enters a raindrop, it bends, or refracts the white light, because light slows down as it moves from air into water. Inside the drop, some of that light reflects off the back surface, and then it refracts again as it exits the droplet.
That combination of refraction and reflection spreads the incoming white sunlight into the different colors of the visible spectrum, red, orange, yellow, green, blue, indigo, and violet. Each color bends by a slightly different amount as it passes through the raindrop, which is why the colors separate and appear as a rainbow.
Two ingredients are essential for a rainbow. If it’s completely overcast and rainy, you won’t see one because there’s no direct sunlight reaching the raindrops. And if the sun is shining but there’s no rain to be seen, there’s nothing to refract and reflect the light. But when sunshine and rain occur together, the conditions are just right for a rainbow to appear.
Andrea sent this rainbow picture as the storms were moving out of Richmond Wednesday. She used www.click2pins.com.
The bowing is always beautiful. And the bending of a rainbow is caused by the speed of the individual colors. Red travels fast so it bends the least. It is at the top of the rainbow.
Violet travels show so it gets bent the most. Violet is at the bottom of the rainbow.
Patrick took this gorgeous photo in Rosenberg using click2pins.com .
What may surprise you is there is always a second rainbow 8° above the primary rainbow. The second rainbow is always fainter and sometimes difficult to see, but it’s always there. The second rainbow is formed because of double reflection and that doubling makes it fainter.
The two internal reflections of light is also why secondary rainbows have the colors flipped with violet on top and red on the bottom. So the next time you spot a bright rainbow, it’s worth taking a second look just above it, you might catch a glimpse of its quieter companion.
The below picture illustrates this perfectly. The primary rainbow’s colors have red on the outside and violet on the inside.
The second rainbow starts with red on the inside and violet on the outside.
What I love most about rainbows is how personal they are. Did you know we all see our own rainbow that belongs to only us?
That’s because a rainbow isn’t a fixed object sitting in the sky. The colors you see are created by sunlight interacting with specific raindrops that send light directly to your eyes. Move even a short distance, and you’re looking at a different set of raindrops creating the rainbow.
So, the rainbow you see will be different from the one seen by someone standing 20 feet away. What I see in Houston will look different from a friend in Katy even with the same line of thunderstorms.
In other words, every rainbow is unique to the person viewing it which makes those post-storms moments in the sky feel even more special.
When the next storms come around I’d love to see your storm pics. Simply send them using www.click2pins.com