Fingerprinting by Spectroscope

And with the spectroscope, scientists have been able to establish a kind of atomic fingerprinting system which labels matter according to the composition of the light it emits. It was the spectroscope that made possible the discovery of one of the unknown elements predicted by Mendeleev. 

Sodium sprinkled into a flame gives off a bright yellow light. 

A copper compound thrown into a flame emits a bright green. The light from a strontium compound is crimson. 

The light emitted by each of these elements is characteristic of the element and therefore can be used in its identification. 

To see this light in far greater detail, we can pass it through a prism, or through a diffraction grating, which acts like a long line of equally spaced, microscopic prisms. 

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