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An enlightening experiment – optical dispersion experiment to create a rainbow of colors with a mirror and glass of water.

Dispersive prism splitting sunlight into colors

Using a mirror to check out the properties of light


Light traveling in a straight line appears colorless. But there’s more to light than just colorless nothingness. When light passes through a wedge-shaped piece of glass called a prism, the light is separated into 7 different and unique colors. You see these colors when light passes through rain or moisture producing a rainbow.

  1. Place a mirror in a glass of water at an angle (let it lean against the side of the glass).
  2. Turn the glass so the mirror is facing the sun.
  3. Hold the paper at a slant in front of the glass. Move the paper around until you see the rainbow colors. You may need to move the paper around until the colors come into full focus.

What you are seeing is the various wavelengths of light broken apart. Sunlight is comprised of seven different colors. A light bulb actually produces redder and orange colors. A fluorescent light has more blue and yellow. This splitting of colors is called optical dispersion.

What is optical dispersion?

White light dispersed by a prism into the colors of the optical spectrum
White light dispersed by a prism into the colors of the optical spectrum (above stripe) compared to a calculated rainbow (below).

Optical dispersion is the phenomenon where different wavelengths of light travel at different speeds through a medium, like a prism. This results in the separation of white light into its individual colors when it passes through the prism.

The amount of dispersion that occurs is dependent on the refractive index of the medium, which is a measure of how much the speed of light is reduced when passing through the medium. Materials with a high refractive index, such as diamond, exhibit a greater amount of dispersion than materials with a lower refractive index, such as air.

Optical dispersion has numerous practical applications in fields such as spectroscopy, telecommunications, and optical fiber technology. It is also a key factor in the design and manufacture of lenses for cameras and other optical instruments, as it affects the extent to which different colors are focused at the same point.

Image Credits

In-Article Image Credits

Dispersive prism splitting sunlight into colors via Wikimedia Commons with usage type - Creative Commons License. July 29, 2013
White light dispersed by a prism into the colors of the optical spectrum via Wikimedia Commons with usage type - GNU Free. April 10, 2009

Featured Image Credit

Dispersive prism splitting sunlight into colors via Wikimedia Commons with usage type - Creative Commons License. July 29, 2013

 

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