How does a rainbow form its perfect arc in the sky? It’s all about the angle between sunlight and water droplets. This angle helps us predict when and where we can spot these colorful wonders in nature.
When Will You See the Perfect Rainbow?
Suppose, I am teaching my Earth Science class today about rainbows. We stand outside after a light rain, with the sun behind us. The sun sits at 35 degrees above the horizon. I want my students to understand where to look for the rainbow.
Let’s Find Our Rainbow Angle
- Remember the magic number:
Primary rainbow angle = 42 degrees from the antisolar point - Calculate viewing position:
- Sun height = 35 degrees
- Rainbow center point = directly opposite the sun
- Primary bow radius = 42 degrees
- Work it out:
- Look opposite to the sun
- Rainbow height = 42° – 35° = 7° above horizon
- Full arc forms when sun is below 42°
This means our rainbow will appear as a partial arc, with its peak just 7 degrees above the horizon!
Quick Tip:
Want to find a rainbow? Stand with your back to the sun and raise your hand at a 42-degree angle. That’s where the primary rainbow will appear!
Why Use the Calculator?
It helps predict the best time and position to see or photograph rainbows. Perfect for photographers and weather enthusiasts who want to catch that magical moment.
FAQs:
Q: Can you see a rainbow at noon?
A: Usually not, as the sun is too high in the sky.
Q: Why is the angle always 42 degrees?
A: It’s fixed by how light bends in water drops.
Q: Can there be a rainbow at night?
A: Yes, with a bright moon (called a moon bow)!