"If we were to isolate each enantiomer in pure form, we would find that we could not distinguish between them on the basis of their physical properties, such as boiling points, melting points, and densities. This result should not surprise us: Their bonds are identical and so are their energy contents. However, when a special kind of light, called plane-polarized light, is passed through a sample of one of the enantiomers, the plane of polarization of the incoming light is rotatedin one direction (either clockwise or counterclockwise). When the same experiment is repeated with the other enantiomer, the plane of the polarized light is rotated by exactly the same amount but in the opposite direction."