How do rainbows work?

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Slide 1: Vidéo
Science

Cette leçon contient 19 diapositives, avec quiz interactifs, diapositives de texte et 1 vidéo.

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Slide 1 - Vidéo

What is a rainbow? 
A rainbow is an arc of spectral colors that appears in the sky opposite the sun as a result of refractive dispersion of sunlight in drops of rain. So, what does that mean? A rainbow is an arc of colors that appear in the sky when it is raining in one part of the sky and sunny in another.

Slide 2 - Diapositive

How does a rainbow form?
A rainbow forms when the sun shines through water droplets (rain drops) while it’s raining or was recently raining.

Slide 3 - Diapositive

How does that happen?
Sunlight comes from the sun. The sun is located in space. Sunlight has to travel through space and to earth, it does that in what scientists call wavelengths.

Slide 4 - Diapositive

Scientist Isaac Newton explained how a rainbow forms.
He said sunlight is really made up of the colors of the rainbow. When those colors are all mixed together it is called white light. White light is the light we see every day. When sunlight travels through the air in the same direction we see white light. When the sunlight enters through a raindrop the colors separate causing us to see a rainbow. 

Slide 5 - Diapositive

Do you want to hear something cool?
 Each raindrop makes its own rainbow! that’s right every water droplet makes its own rainbow, but it takes millions of raindrops for us to see a rainbow.

Slide 6 - Diapositive

What are the colors of the rainbow?
The colors of the rainbow are red, orange, yellow, green, blue, indigo, and violet.

Slide 7 - Diapositive

An easy way to remember the
 colors of the rainbow is,        ROY G. BIV.
R: Red
O: Orange
Y: Yellow
G: Green
B: Blue
I: Indigo
V: Violet





Slide 8 - Diapositive

How did the rainbow get its name?
It is believed that the rainbow got its name from its shape. A rainbow’s arc looks similar to a bow for shooting arrows. People also noticed that this colorful arc would only form when it was raining so they called it a rainbow. 

Slide 9 - Diapositive

Have you ever noticed that you don’t see many rainbows in the winter in a cold climate?
This is because in the winter raindrops freeze into snowflakes so fewer raindrops fall. You see more rainbows in tropical locations and by waterfalls.

Slide 10 - Diapositive

What is the only planet in the solar system where rainbows are possible?
Earth is the only planet in the solar system where rainbows are possible.

Slide 11 - Diapositive

Rainbows can occur in what season?
Rainbows can occur in any season. Winter, Spring, Summer, or Fall. 

Slide 12 - Diapositive

Rainbow Fact: rainbows are actually a full circle.
We only see one arch of a rainbow because on the ground we can only see the light reflecting off raindrops that appear above the horizon. Sometimes people traveling in airplanes or other aircraft can see the entire full-circle rainbow.

Slide 13 - Diapositive

What degree angle starting from the direction opposite the sun is a rainbow?
A rainbow arch is a 42-degree angle starting from the direction opposite the sun.

Slide 14 - Diapositive

How many types of rainbows do you think there are? 
There are 9 types of rainbows. The most common is the primary rainbow. 

Slide 15 - Diapositive

The 9 types of rainbows:
1. Primary rainbow 2. Double rainbow 3. Twinned rainbow 4. Full circle rainbow 5. Supernumerary rainbow 6. Reflected rainbow 7. Monochrome rainbow 8. Higher order rainbow 9. Fogbow rainbow 

Slide 16 - Diapositive

What causes a rainbow to form?
A
Refraction of light in water droplets
B
Reflection of light in air
C
Refraction of light in air
D
Reflection of light in water droplets

Slide 17 - Quiz

What are the colors in a rainbow?
A
Red, orange, yellow, green, blue, purple
B
Red, orange, yellow, green, blue, indigo
C
Red, orange, yellow, green, blue, indigo, violet
D
Pink, orange, yellow, green, blue, purple

Slide 18 - Quiz

Why do rainbows appear as semi-circles?
A
Sunlight is stronger in the top half
B
Raindrops fall faster in the top half
C
Gravity pulls the top half downwards
D
The ground obstructs the bottom half

Slide 19 - Quiz