ELI5: how rainbows form

high confidence

March 30, 2026

// explanation

// eli5A rainbow is like magic paint made by the sun and water droplets! When sunlight shines through raindrops, the light bends and bounces inside the drops, like when you shine a flashlight through a water bottle [1][2]. The light splits into all the colors we see - red, orange, yellow, green, blue, indigo, and violet - because different colors bend at different angles [5]. You need two things: sunshine from behind you and water droplets (like rain or fog) in front of you [5].

// sources

[1]What Causes a Rainbow? | NESDIS

A rainbow is caused by sunlight and atmospheric conditions. Light enters a water droplet, slowing down and bending as it goes from air to denser water.

[2]How Are Rainbows Formed? | Royal Meteorological Society

Apr 28, 2020 ... Rainbows are formed when light from the sun is scattered by water droplets (eg raindrops or fog) through a process called refraction.

[3]How Do Rainbows Form? - National Weather Service

The rainbow we normally see is called the primary rainbow and is produced from one internal reflection. The secondary rainbow arises from two internal ...

[4]Rainbow - National Geographic Education

Jan 20, 2026 ... The glow is formed by light passing through raindrops, not reflected by them. Some scientists call this glow a zero-order glow. Double Rainbow.

[5]Ask the Professor: How do rainbows form? | University of Nevada ...

Jun 27, 2024 ... Two key ingredients to form rainbows are sunlight and suspended water droplets. Sunlight appears white and is composed of electromagnetic waves of different ...

[6]How is the Rainbow Formed? 🌈 w/ Neil deGrasse Tysonvideo

Video by Cosmic Shorts

[7]How Is A Rainbow Formed | The Dr. Binocs Show | Learn Videos For Kidsvideo

Video by Peekaboo Kidz

[8]Neil deGrasse Tyson Explains Rainbowsvideo

Video by StarTalk

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