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Optical Rotatory Dispersion: Polarized Light and Sucrose Solution in a Tall Cylinder

White light is passed through a cylinder filled with sucrose solution and the variation of color with distance is shown.

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Narrative
When plane polarized white light from an overhead projector is passed through a cylinder of sucrose solution a spiral rainbow is observed perpendicular to the cylinder. When white light passes through a polarizer, the extent of rotation of light depends on its wavelength. Short wavelengths are rotated more than longer wavelengths. Because the wavelength of light determines its color, the variation of color with distance through the tube is observed. A second polarizing filter is placed on top of the cylinder and is rotated to display the range of transmitted colors. This dependence of specific rotation on wavelength is called optical rotatory dispersion.