A rainbow has 7 colours in this order, from the outer edge to the inner edge: red, orange, yellow, green, blue, indigo and violet. The scientist Isaac Newton drew up this list back in the 17th century, by splitting white light through a prism.
👉 In short: the colours of the rainbow in order are, from the outer edge to the inner edge:
1. Red → 2. Orange → 3. Yellow → 4. Green → 5. Blue → 6. Indigo → 7. Violet
This order of the rainbow’s colours never changes: it depends on the wavelength of the light. To remember it, just think of the friendly name Roy G. Biv (Red, Orange, Yellow, Green, Blue, Indigo, Violet). 🌈
- The exact order of the seven rainbow colours
- The science behind this colourful ribbon
- Why Isaac Newton chose the number seven
- Easy ways to memorise the order
- Double rainbows and rare optical effects
- Experiments to make a rainbow at home
🌈 The exact order of the seven rainbow colours
When you look up at the sky, you often spot that perfect gradient that seems to follow an unbreakable rule. Here is how these shades line up in real life.
🎨 The official list from red to violet
The seven colours always run from the outside to the inside: red, orange, yellow, green, blue, indigo and violet. Red always borders the outer part of the visible arc.
This pattern follows a precise layout, like this:
- Red (outer edge)
- Orange
- Yellow
- Green
- Blue
- Indigo
- Violet (inner edge)
The curve comes from refraction.
This visual order is universal. It stays the same, no matter where you happen to watch this lovely weather wonder.
🔢 Why this order never changes
Where each shade sits depends directly on its wavelength. Red has the longest one, while violet has the shortest. It’s pure physics.
The human eye picks up these waves in a steady way. The brain reads the electrical signals without ever flipping the visible spectrum. It’s a smooth, built-in process.
Light bends according to strict mathematical laws, forcing red to stay the ambassador of the long waves on the outside of the arc.
🟣 Indigo’s special spot
Indigo slips in between blue and violet. It’s a dark, deep shade. It acts as a visual bridge between these two zones of the light spectrum.
Whether you can really see it is actually up for debate. Lots of people struggle to tell it apart from dark blue. Some scientists even think it’s a bit unnecessary.
But it’s still part of our habits. It’s a piece of history that we happily keep passing on to children.
🌈 In what order are the colours of the rainbow?
The seven colours of the rainbow always sit in this exact order, from the outside to the inside of the arc: red, orange, yellow, green, blue, indigo and violet. It’s the only order possible, because each colour holds a fixed spot based on its wavelength. 📏
| Position | Colour | Wavelength | To help you remember |
|---|---|---|---|
| 1 (outer edge) | 🔴 Red | ~700 nm (the longest) | A lovely ripe tomato |
| 2 | 🟠 Orange | ~620 nm | A crunchy carrot |
| 3 | 🟡 Yellow | ~580 nm | The sun or a lemon |
| 4 (middle) | 🟢 Green | ~530 nm | The grass in the garden |
| 5 | 🔵 Blue | ~470 nm | The summer sky |
| 6 | 🟣 Indigo | ~445 nm | A deep midnight blue |
| 7 (inner edge) | 🟪 Violet | ~400 nm (the shortest) | A violet flower |
A tip for parents: to lock this order in for good, nothing beats playing with it through a colour-by-number activity. Your child then links each shade to its place in the list. ✏️
🔬 The science behind this colourful ribbon
Knowing the order of the colours is one thing, but understanding how nature builds this show is another, and far more technical.
💧 The role of raindrops and sunlight
To enjoy this show, the sun has to be behind you. The rain has to fall right in front of your eyes. That’s the basic rule.
Light enters the water drop. It then bounces off the back inner wall. Finally, it heads back towards us to amaze us.
Each tiny raindrop works like a minuscule spherical mirror, sending the light back after trapping it for a brief moment.
💡 Refraction, or how white light is split apart
When it moves from one material to another, from air into water, light bends. Each colour changes direction by its own angle. This is what we call refraction.
Light isn’t really white. It hides every shade inside itself. Passing through the water then reveals this hidden spectrum.
The water drop becomes a natural prism. It sorts the parts of the light to make them finally visible to the naked eye.
✨ How the size of the drops changes the brightness
The width of the drops changes everything. Big storm drops give very bright colours. The contrast then becomes truly striking for anyone watching.
With small drops, diffraction takes over. The shades then blend together. They end up fading into a white veil.
| Drop size | Colour intensity | Type of effect |
|---|---|---|
| Big drops (>2 mm) | Saturated colours | Bright rainbow |
| Medium drops (0.5 mm) | Standard colours | Classic rainbow |
| Mist (<0.05 mm) | White or pale arc | Fog bow |
In short, the weather decides how good the picture will be. The order and explanation of the rainbow’s 7 colours depend directly on the size of these little water pearls.
🧑🔬 Why Isaac Newton chose the number seven
Physics may explain the light, but it was a famous man who decided to fix this number of seven colours in our minds.
🎵 A likeness he wanted with the musical notes
Isaac Newton saw a striking link between the colours and the musical scale. For him, the universe simply had to be ruled by an overall harmony. That was his deep belief.
There were seven notes in the scale, so there had to be seven colours in the arc. His view was as mystical as it was scientific for the time. He looked for mathematical order everywhere.
So he added orange and indigo to his list. Without that deliberate choice, he would only have counted five main colours. The number didn’t add up for him.
📊 The difference between a continuous spectrum and made-up divisions
The physical reality differs from the way we usually split it up. In nature, the arc is an endless gradient. There’s no sharp border between the shades. It’s a smooth, seamless continuum.
So the number seven is just a human convention. Other cultures see three or six colours depending on their own language. It all depends on how we name things.
Yet our brain loves to sort the things it sees. We need precise names to make sense of our surroundings. It feels more reassuring to our minds that way.
📚 Pythagoras’s legacy in our textbooks
The influence of the ancient world played a major part. Newton admired Pythagoras’s ideas about sacred numbers. The number seven held a special aura of perfect completeness back then.
This rule lasts because school textbooks simply copied this work. It has gone on for centuries now. It has become a teaching truth that nobody really questions.
Today, we still learn it by heart from our earliest school days. It’s a shared foundation of our general knowledge. That’s how the tradition keeps going naturally.
🧠 Easy ways to memorise the order
Remembering this list isn’t always easy for younger ones, but a few memory tricks sort out the problem in a flash.
💬 The famous friendly name Roy G. Biv
You can use the classic name “Roy G. Biv”. Each letter matches exactly one colour from the official list drawn up by Newton: Red, Orange, Yellow, Green, Blue, Indigo and Violet.
This method works brilliantly because the brain prefers slightly silly little stories to technical lists. It’s a perfect tool to help schoolchildren with their homework.
You just repeat that short little name. The order of the colours then comes straight back to mind without any effort at all.
🔤 The handy phrase to remember
Another trick is a short phrase where each first letter stands for a colour. Try: “Richard Of York Gave Battle In Vain”. That gives you Red, Orange, Yellow, Green, Blue, Indigo and Violet.
To avoid mix-ups, remember that red leads the way on the outside. Green sits right in the middle of the arc.
This is often the favourite method of scientists. It stays quick and leaves no room for doubt during a test or an observation.
🖼️ Making your own mental pictures with the children
You can suggest links to familiar objects. A tomato for red, or a carrot for orange. Picturing a basket of colourful fruit helps your memory enormously.
Encouraging drawing is also a great idea. Colouring a rainbow fixes the visual memories for good. The child takes ownership of the shades by handling their own coloured pencils.
Play is still the best teacher at home. While having fun, you remember the 7 colours of the rainbow, their order and the science behind them, without even noticing.
✨ Double rainbows and rare optical effects
Sometimes the sky gives us an unexpected bonus in the shape of a second arc, fainter and more mysterious.
🔄 The mystery of the secondary arc and its flipped colours
The light bounces twice inside the drop. This complex path needs more energy. It also needs a special precision of light to appear.
Red ends up on the inside of this second arc. Violet shifts to the outside. It’s the exact opposite of the first ribbon. This flip often surprises those who watch closely.
This arc is always paler. The second reflection loses part of the sun’s original strength.
⚫ Alexander’s dark band between two glows
A less bright zone sometimes appears. It sits exactly between the two arcs. The sky there looks noticeably greyer or darker.
In this space, no light is sent back to the watcher by the drops. It’s a fascinating optical gap. The rays simply aren’t bent towards our eyes.
This shadowy zone, named in honour of Alexander of Aphrodisias, highlights by contrast the brightness of the arcs around it.
🌕 Supernumerary arcs and moonbows
Extra fringes sometimes hide there. They are little pink or green arcs below the first one. They come from complex light interference.
Moonbows are part of the show too. They appear at night thanks to the light of the Moon. Their colours are very hard to make out for our night-time eyes.
Here are a few rare types to look out for:
- Supernumerary arcs
- Moonbows
- White arcs (fog)
🧪 Experiments to make a rainbow at home
You don’t have to wait for a storm to admire these colours, because you can recreate this physics miracle in your own garden.
✈️ Why the arc is a full circle seen from a plane
The geometry of this effect often surprises people. A rainbow is really a cone of light. Seen from above, it draws a perfect circle. This circle is centred on the point opposite the sun.
On the ground, the horizon spoils the fun. The earth simply cuts off the lower part of the circle of light. That’s why we only see a coloured half-circle from our garden.
Airline pilots regularly see this whole circle. It’s a magnificent and quite rare sight. They fly over the rain with the sun behind them.
👣 Why you can never touch the end of the arc
It’s only an optical image. It isn’t a solid object sitting in a field. The arc actually exists only in your own gaze.
If you move forward, the arc moves too. The angle between your eyes, the water and the sun stays the same. So the end of the arc always seems to run away from you.
Chasing the end of a rainbow is a hopeless quest, because it’s only a projection of light tied to your own position.
💦 Three tests with a simple garden hose
Take your hose out on a lovely sunny day. Turn your back to the sun to get into position. Then spray a very fine mist of water.
Look for the right reflection by slowly moving the jet of water. The 7 colours of the rainbow will then appear in the droplets. The show is instant and really rewarding.
- Sun behind you
- A fine mist needed
- An angle of about 42 degrees
Remembering the order of the rainbow’s seven colours becomes child’s play thanks to refraction and our memory tricks. Have fun making your own spectrum with a simple jet of water the next time the sun comes out. Turn every shower into a bright, colourful science adventure!
❓ FAQ
🌈 What is the exact order of the colours in a rainbow?
The order of the seven colours is always the same, from the outside to the inside of the arc: red, orange, yellow, green, blue, indigo and violet. This unchanging sequence is set by physics and the way light splits apart.
If you spot a second arc higher up in the sky, just know that the order there is flipped by a double-reflection effect. Red ends up on the inside and violet on the outside. It’s a little magic trick from nature!
🔢 Why do we count exactly seven colours?
We owe this number to the famous scientist Isaac Newton. In the 17th century, he chose to split the spectrum of light into seven shades to create harmony with the seven notes of the musical scale. He even added orange and indigo to make the number add up.
In reality, a rainbow is a continuous gradient with endless shades. So the number seven is a historical and cultural convention that we keep passing on to our children in school books.
💡 Is there a trick to remember this order easily?
Of course, and it’s really handy for helping the little ones (and the grown-ups)! You can remember the name “Roy G. Biv”, or the phrase “Richard Of York Gave Battle In Vain”. The first letter of each part stands for a colour: Red, Orange, Yellow, Green, Blue, Indigo and Violet.
With either trick, there’s no more hesitation possible before your next colouring session!
🌦️ How does a rainbow actually form?
This pretty show appears when two conditions come together: rain and sun. The rays of light pass through the water drops, which act like tiny prisms. The white light is then bent and split into several colours — this is what we call refraction.
To spot it, you always need the sun behind you and the rain in front of you. Each droplet sends the light back towards your eyes, creating this colourful ribbon that seems to float in the air.
👣 Can you really find the end of a rainbow?
Sadly for the treasure legend, it’s impossible to reach the end of a rainbow. It isn’t a fixed physical object, but an optical effect that depends on your position. If you move forward, the arc moves with you at the same distance.
It’s a bit like a horizon that keeps backing away. A rainbow only exists in your gaze, thanks to the precise angle between the sun, the water and your eyes. That’s what makes every sighting unique for the person watching.
