How are colors arranged in the secondary rainbow?

Reversed, with red on the inside

What are supernumerary bows?

Faint extra bands inside the primary bow

Double Rainbow Quiz: The Optics Behind Two Colored Arcs

A second bow appears when sunlight reflects twice inside raindrops, and this double rainbow quiz explains the optics behind the colors. Play an interactive set of 10 questions on the 42 and 51 degree angles, reversed colors, Alexander's dark band, supernumerary bows, René Descartes, Isaac Newton and full-circle rainbows seen from aircraft.

Start Double Rainbow Quiz

🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

Primary
How many reflections inside a raindrop create the primary rainbow?
Secondary
How many internal reflections form the secondary rainbow?
Colors
How are colors arranged in the secondary rainbow?
Angle
At about what angle from the antisolar point does the primary bow appear?
Band
What is the darker sky between the two bows called?
Sun
Where must the Sun be to see a rainbow?
Descartes
Who explained the rainbow's angles with geometry in 1637?
Newton
Who showed that white light splits into colors?
Supernumerary
What are supernumerary bows?
Circle
What shape is a rainbow when seen from an airplane?

Explanations: answer key for all 10 questions

Q1: How many reflections inside a raindrop create the primary rainbow?
Answer: One
Light refracts, reflects once and refracts again.
Q2: How many internal reflections form the secondary rainbow?
Answer: Two
The extra reflection makes it fainter.
Q3: How are colors arranged in the secondary rainbow?
Answer: Reversed, with red on the inside
The second reflection flips the order.
Q4: At about what angle from the antisolar point does the primary bow appear?
Answer: 42 degrees
The secondary bow sits at about 51 degrees.
Q5: What is the darker sky between the two bows called?
Answer: Alexander's dark band
It is named after Alexander of Aphrodisias, who described it around 200 CE.
Q6: Where must the Sun be to see a rainbow?
Answer: Behind you
Rainbows appear opposite the Sun.
Q7: Who explained the rainbow's angles with geometry in 1637?
Answer: René Descartes
He traced light paths through a glass globe of water.
Q8: Who showed that white light splits into colors?
Answer: Isaac Newton
His prism experiments explained the spectrum.
Q9: What are supernumerary bows?
Answer: Faint extra bands inside the primary bow
They come from interference of light waves.
Q10: What shape is a rainbow when seen from an airplane?
Answer: A full circle
On the ground, the horizon hides the lower half.

Double Rainbow Quiz – The Optics of Two Arcs

A rainbow forms when sunlight enters raindrops, bends, reflects inside and bends again as it exits, splitting into colors. The primary bow, from one internal reflection, appears about 42 degrees from the point opposite the Sun.

A secondary rainbow forms from two internal reflections. It appears at about 51 degrees, is fainter and has its colors reversed. The darker sky between the two bows is called Alexander's dark band.

René Descartes explained the geometry in 1637, and Isaac Newton explained the colors. Faint supernumerary bands come from light-wave interference, and from an airplane a rainbow can appear as a full circle.

What This Quiz Teaches

Science students and sky watchers will enjoy these questions.

How rainbows form
Why the second bow differs
What the dark band is
Who explained rainbows
Why some rainbows are circles

Did You Know?

Moonbows are rainbows made by moonlight.
Fogbows are nearly white.
Each person sees their own rainbow.
Rainbows are common in Hawaii.
A viral 2010 video celebrated a double rainbow in Yosemite.