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Spectroscopy ~ Separating Light




Heated gases of elements in sealed glass tubes are called "spectrum" tubes and they emit a certain color of light. Observing these tubes with diffraction gratings is a common lab in Astronomy.


A diffraction grating acts like a prism and separates light into its component colors.


The excited atoms release the energy they gained. Some of this energy is in the form of heat and some is in the form of light.

The billions of excited atoms release energy. Each excited atom releases a single pulse of light energy, called a photon, as it returns to the "ground" state or low energy state.

The kind of photons that are emitted by atoms is unique for an element.


The color seen by the naked eye is a combination of a number of colors of light. A spectroscope or diffraction grating can separate the light produced by an emission tube into emission lines. These can be seen when you look through the spectroscope at the light source. You will be able to observe the "line" spectrum for the elements and record the spectral lines.


Instructions for making your own diffraction grating are here.