A rainbow is an arc that shows all the colors, with their different wavelengths, that make up visible light. Seven colors make up a rainbow, and they always appear in the same order: red, with the longest wavelength, is on the top, followed by orange, yellow, green, blue, indigo (a deep reddish-blue that is often difficult to see), and violet, which has the shortest wavelength. A good way to remember the order of those colors is by taking the first letter of each to spell “ROYGBIV,” pronounced “roy-jee-biv.”
A rainbow occurs when sunlight passes through water droplets and is refracted or bent by their rounded shape into separate wavelengths. Rainbows can sometimes be spotted in the spray of lawn sprinklers, in the mist of waterfalls, and most spectacularly in the sky during a rain shower when the Sun is still shining. A rainbow appears in the part of the sky opposite the Sun. Because the Sun must also be low in the sky, near the horizon, late afternoon is the best time to look for a rainbow if the day has been sunny with a few short rain showers or thunderstorms.
- Why are rain clouds gray?
- Why do jet airplanes leave white trails in the sky?
- How do clouds float?
- Can it rain cats and dogs?
- What are clouds made of?
- Where is the windiest place on Earth?
- How do we see the wind?
- Why is the sky blue?
- How does the greenhouse effect work on Earth?
- Is it true that at one time there was no oxygen?
- Why is the ozone layer important to Earth?
- What is air made of?
- Why is Earth mostly crater-free compared to the pockmarked Moon?
- Why does the Moon follow us when we’re driving?
- How does the Moon affect the ocean tides?
- Does the Moon really have volcanoes?
- How high could you jump on the Moon?
- What are moonquakes?
- Is there a Man in the Moon?
- Which planets experience the greenhouse effect?
