(BigCountryHomepage.com) – In this experiment of the summer series of Kayleigh’s Weather Workshop, we’re taking a look at the age-old question: ‘why is the sky blue?’ Meteorologist Kayleigh Thomas helps us understand that what seems like a difficult question to answer, can be broken down into simple parts thanks to science! 


Fill the container about three-fourths full of water.

Prop the flashlight up so it will shine through the container from the side.

Add about a teaspoon of milk to the water, just enough to make the water cloudy, and use the spoon to stir.

What do you see?

Continue to add milk until you start to see a blue light in the container. Or, take the piece of paper and place it in the path of the light to see if the light is blue.

You can play around with where the flashlight is placed, as well. Try holding it below your container, or at an angle to see if any other colors of light show.

For extra fun, you can continue to add milk to the water until you see more of an orange or red light!

What is happening

It all comes down to light, more specifically, light from the sun. Sunlight appears white to our eyes, but is really made up of all the colors of the rainbow. When that white light shines through a prism, it can be separated into all of its colors.  

Why are there different colors?

The light that we see is just one small part of the light energy moving around us. Light energy travels in waves, the wavelength is what makes one kind of light different from another.

BCH graphic via Canva: Visible light spectrum and its wavelengths (Jul. 2022)

Visible light includes the range of wavelengths that we can see. The longer wavelengths appear red to us, while the shortest wavelengths look blue or violet.  

National Aeronautics and Space Administration, Science Mission Directorate. (2010). Wave Behaviors. Retrieved July 27, 2022, from NASA Science website: https://trib.al/LvgxAB8

One thing to keep in mind, all light travels in a straight line unless something gets in the way that can reflect it, bend it, or scatter it like molecules of the gasses in the atmosphere.  

Why do we see only blue?

When sunlight enters the atmosphere, most of the red, yellow, and green wavelengths pass through the atmosphere. This combination of colors still appears nearly white to our eyes. However, the blue and violet light wavelengths are small enough to be scattered by the molecules in the atmosphere.  

The scattered violet and blue dominate the sky and makes it appear blue to our eyes because our eyes are not as sensitive to violet light as they are to blue. 

This same process is what can make for those gorgeous red-ish sunsets. The sun gets lower in the sky as it sets, and therefore has to pass through more of the atmosphere to reach your eyes.

Almost all of the blue and violet light is scattered out which allows the reds and yellows to be seen. Larger particles of dust, pollution, smoke, and water vapor reflect and scatter more reds and yellows.

Taylor county saw this when the Mesquite Heat Fire burned and left a red glow.  

Come back for our last Summer Series Weather Workshop on August 11. We stream to KTAB and KRBC‘s Facebook pages live at 4:30 p.m. every other Thursday!

If you have any weather questions or experiments you want to see, send Meteorologist Kayleigh Thomas an email by clicking here. See you soon!