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Breaking down white light into the colors of the rainbow using prisms.
Have you ever wondered where the colors of a rainbow come from when the sun looks 'white'? What if I told you that every beam of sunlight is actually a hidden package of seven different colors just waiting to be let out?
White light might look plain, but it is actually a spectrum. This is a collection of different colors traveling together. When light moves from air into something clear like glass or water, it slows down and bends. This bending is called refraction. Because each color in the white light travels at a slightly different speed, they don't all bend the same amount! This is the secret to 'breaking' light apart.
Quick Check
What is the scientific term for when light bends as it moves from one material to another?
Answer
Refraction
A prism is a special tool, usually a triangular piece of glass, used to study light. When white light enters the prism, the glass acts like a 'speed bump.' Red light is the fastest and bends the least. Violet light is the slowest and bends the most. This separation spreads the colors out so we can see them individually. We remember the order using the name ROYGBIV: Red, Orange, Yellow, Green, Blue, Indigo, and Violet.
To remember the spectrum, we use the acronym . 1. Red 2. Orange 3. Yellow 4. Green 5. Blue 6. Indigo 7. Violet Think of it as a person's name: Roy G. Biv!
Quick Check
In the acronym ROYGBIV, which color comes between Yellow and Blue?
Answer
Green
You don't need a glass prism to see a spectrum; nature uses water! After a rainstorm, millions of tiny raindrops hang in the air. When sunlight hits these drops, the light enters the water, bends, reflects off the back of the drop, and bends again as it leaves. Each raindrop acts like a tiny prism. Because there are billions of drops, they create the giant colorful arc we call a rainbow.
To see a rainbow, you need specific conditions: 1. The sun must be shining behind you. 2. There must be water droplets (rain or mist) in front of you. 3. The light must travel into the drop and reflect back at an angle of about for you to see the colors clearly.
Which color of light bends the LEAST when passing through a prism?
What acts as a prism to create a rainbow in the sky?
White light is made of only one single color.
Review Tomorrow
In 24 hours, try to write down the name 'Roy G. Biv' and see if you can list all seven colors it represents without looking at your notes.
Practice Activity
Try this on your own: Take a glass of water to a sunny window. Place it on a piece of white paper and see if you can catch the sunlight to create a small rainbow on the paper!