ALTOONA, Pa. (WTAJ) — In this episode of Science with Shields, Christy Shields shows you why the sky is blue.

What you need: 

  1. Flashlight
  2. Soap/Milk
  3. A clear glass
  4. Water


It is best to do this experiment in a dark room. First, fill your glass up with water. Add soap to get a milky color. You can also use milk to achieve this. Point the flashlight at the cloudy solution and notice how the mixture gets a light hint of blue!


The sky is blue because of the scattering of light. Like sunlight, the white light from the flashlight is made up of a rainbow of colors. We don’t see all of these colors individually, but just as a white light . Once the light is scattered through an object, we can see individual colors. Blue light has a shorter wavelength than the other colors scattered. This is why we see blue tint to the solution in the glass.

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The sky is blue from the refraction of light. Light bends when passing through the air to another medium, for example, like water. When it’s a clear day, the sunlight goes through then atmosphere and the light is scattered through the air molecules giving the sky its blue color. Again remember, its because blue has a shorter wavelength then the other colors. Also, blue is a color that is easier to see with the human eye compared to some other colors.