What is Spectral line?
[[File:Spectral lines continuous.png|thumb|Continuous spectrum]] [[File:Spectral lines emission.png|thumb|Emission lines]] [[File:Spectral lines absorption.png|thumb|Absorption lines]] A '''spectral line''' is the way scientists can tell one element from another by looking at color. == The colors of the rainbow == In order to understand '''spectral lines''', [[color]] has to be understood. In a [[rainbow]], the colors of light go from [[purple]] to [[red]]. Several hundred years ago, the famous scientist [[Isaac Newton]] did an experiment where he showed that even white [[light]] from the [[Sun]] was made up of all the colors of the [[rainbow]]. When other scientists following him looked at this rainbow very closely, they noticed that there were dark lines breaking up the rainbow, where certain shades of [[color]]s should be. These lines were very small, but could be seen when the rainbow got stretched out very far. They investigated this further, and discovered that certain [[chemical element]]s, like the [[hydrogen]] and [[helium]] that make up the [[Sun]], absorbed certain frequencies of [[light]] where those [[color]]s should be, like a sponge absorbs water, but does not absorb chalk. == Elemental fingerprints == Soon, [[scientist]]s discovered that when they heated other [[chemical element]]s, like [[calcium]] and [[oxygen]], so hot that they shined with a white [[light]], they found similar lines, but in different places. No two [[chemical element]]s had these lines in exactly the same places along the rainbow, and they also soon discovered that could be used to be able to tell what [[star]]s were made up of in the [[Universe]]. The lines that a particular element produces are called the [[emission spectrum]] of that element. The reason the [[chemical element]]s can do this is because of the number and places of [[electron]]s orbiting around the center of each [[atom]] of each [[chemical element]]. These [[electron]]s, when [[light]] hits them, absorb a specific [[wavelength]], or [[color]] of [[light]