What Is Flame Emission Spectroscopy?

I have never heard of turning a compound into an aerosol and putting it through a flame, but when I took a chemistry course in college, we did a couple of experiments using a spectroscope to determine chemical compositions. One of the things we did was look at different elements that had been put into a vacuum tube and then had electricity passed through it to excite the electrons. Basically, where a normal fluorescent light bulb would have mostly argon in it, these tubes had things like hydrogen and helium. They were much smaller than a light bulb, too.

After they had the electricity going through them, they would glow a certain color. Then you could look through the spectroscope, and it would break apart the spectrum into the specific wavelengths, and you could record them and compare them to the charts mentioned from the article.

We had a couple things like salts that were two elements in the same tube. The different spectra overlap, but you can start to figure out the elements eventually. Of course, in a real scientific setting, you can make computers do most of it.

@JimmyT - From what I know, flame spectroscopy is widely used in astronomy to test the elemental composition of stars and other things out in space. As you can imagine, the heat from stars is pretty good at burning up the various elements and emitting their spectrums into space. Astronomers can use special telescopes outfitted with spectrometers to look at the star emissions and tell what elements are present in them. This is important, since stars of different ages and sizes are made of different elements and burn at different temperatures.

I'm not positive on this, but I think astronomers are able to use emissions spectroscopy to determine the composition of planets, too. Nothing from Earth has ever visited Pluto, but we still know what its atmosphere and surface are made of. I'm sure there are some other uses I am not familiar with, as well.

@JimmyT - Those are some good questions. I don't think I had thought about all those things. I can tell you what I know, though, since we were doing this in my chemistry class the other day.

We just looked at a few things and the different colors they made. We tried copper, and it did turn green. When we did lithium it was pink, and sodium was kind of an orange color the same as the flame. The experiment we did, though, was basically just to help us understand how the electrons can change levels. We didn't really get too in depth about how real chemists would use those results in a lab setting.

The one thing that my teacher told us, though, is that burning the different elements is how they produce a lot of fireworks. They just pack the shells with different solid elements, and then when the firework explodes, it burns them and produces the different colors. I thought that was pretty interesting.

When would someone even use something like this. I mean, I don't really remember a lot about when I took chemistry, but I understand how electrons can change energy levels within an atom. If I remember correctly, that is how a light bulb works.

I suppose there would be some instances like the article mentions where you could burn a piece of material and check the resulting spectrum, but it seems like there would usually be a lot more precise and less destructive ways you could go about the process. I would assume it takes a pretty large sample of something to get the right response.

Also, what happens when you have a molecule that is made up of more than one element? I would assume that each element emits its own specific wavelengths of light, but how would the chemist go about deciding which of the wavelengths belonged to each specific element. There has to be a certain amount of overlap, right? In other words, some elements would produce some of the same colors.