Sunset in a glass

I’ve been looking up a lot amazed at the beautiful sunrises and sunsets here in Beaumont, TX. Maybe it’s because now that kids are back at school, I’ve been waking up before sunrise, checking out the horizon, and trying to soak in a minute of peace before the rush of the day begins.

I’m almost certain you’ve had the question asked by your kids about “Why is the sky blue?”, I know I have. So, last week we did the super easy and classic experiment of a sunset in a glass to answer this age old question.

What you need: A glass of water, a 1/2 teaspoon of milk, a flashlight with a white light

What you do: 

• Mix 1/2 a teaspoon of milk (or less) in a glass of water
• Turn the lights off
• Point the white light until you see the blue tint – this represents the daytime

• Move the light until it shines off a back wall until you see the yellow orange tint – this represents the evening

What’s the science:

White light contains the full color spectrum in waves. When light hits the particles of milk in one direction, it disrupts the waves so that the blue light is visible. This is what happens when the sun (white light) hits nitrogen and oxygen molecules in the atmosphere so we see the blue color of the spectrum during the day. When the sun’s white light is further away different waves of the color spectrum are visible so we see the yellow orange color spectrum of the sunset.

I know I’ll never look at a sunset the same way again! So if you have a little one asking “Why is the sky blue?” you can say, “Come on, let’s go have a sunset in a glass and we’ll talk. 😉”