NORFOLK, Va. — Today, we will answer the age-old question: why is the sky blue? Let’s take it back to elementary school when we used to play with glass prisms and flashlights.
As kids, we would shine a flashlight on those prisms. The prisms bent the white light from the flashlight. The light then bounced out in the form of a rainbow. This is called refraction.
The molecules in the sky act in a similar way with light from the sun, except that some of the light is absorbed by those particles. The main color that is more easily scattered in the air molecules during the daytime is the blue wavelength. It bounces back and hits our eyes. The rest of the colors in the visible spectrum stay together so they remain white to the eye.
In the weather world, we call this Rayleigh scattering. Rayleigh scattering is most efficient for short wavelengths, which include the colors blue, indigo, and violet. That is why when you look up and observe the sky during the day, the sky is blue.
During sunset, the sky usually becomes a red or orange color. That's because those colors have a long wavelength and can pass through more of the atmosphere when the sun is at that low angle.
Sunlight scattering is important to our weather because it controls how hot or cold we are at the surface. The more sunlight that is reflected up to space, the cooler we'll be.
That's how your weather works!