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Spectrometry activities

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Now that you have a working spectrometer give these experiments a shot. Please add your own activity ideas, and include how much time it'll take, an estimate of the cost, etc. _If you haven't yet, you should first calibrate your spectrometer with a CFL bulb. _

1. Measure gases in the atmosphere

Please note: this will only work with a device that can measure near-infrared light; one based on a modified webcam like the Desktop Spectrometry Kit.

This is a good starting place. Simply go outside during the day and point the spectrometer at an evenly illuminated part of the sky -- cloud or blue sky both work.

Even though air is pretty clear, pointing your spectrometer through miles of the atmosphere places many molecules between your spectrometer and your light source (AKA the sun). Because of the sheer amount of molecules, you can see lines where CO2, O2, O3, and water vapor have absorbed part of the spectrum. These are known as the Frauenhofer lines.

For example, see: https://spectralworkbench.org/analyze/spectrum/913 (image below) and browse other examples here: https://spectralworkbench.org/tag/sunlight

Try different directions in the sky, towards and away from the sun. Where did you point your spectrometer to get the clearest absorption lines? Any idea why? Post a research note with your data and describe what you did.

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2. Point it at different lights

Now let's try using manmade light sources. Go indoors and find some different kinds of light bulbs. Turn them on and point your spectrometer at them. Notice how much less of "the rainbow" you see compared to the sun - see the distinct emission lines of the mercury spectrum from mercury vapor in the lamps.

Incandescent:

Flourescent: (Flourescent spectrum example image)

Neon: See these examples of neon lights: http://publiclab.org/notes/cfastie/2-23-2013/neon

Lasers: Get different colors of lasers - each of which will produce only a narrow band of colored light. Consider how to measure it without overloading the spectrometer with too much light.

What's next?

Try some more advanced tests. You'll need more supplies beyond what comes in the kit for these tests.

Detect sodium in table salt

15-20 minutes, 1 candle, bunsen burner or propane burner With a candle and a small spray bottle of salt water, you can measure the emission spectrum of the sodium in table salt. Read more about this type of activity here

Advanced tests

Help advance this project -- please share your results if you manage to record data of one of these!

Measure other things in your kitchen

Try scanning a solution of alum? Mineral supplements dissolved in water? http://www.amazon.com/b/ref=dp_brw_link?node=3774271

Oils

Motor / Olive - compare two types of oil Garage version: get oil from your car

Laundry detergents

Try to detect blueing dyes in laundy detergent UV light:

Beer's Law

Varying concentrations of liquids like coffee, wine, soda, juice. Try to demonstrate Beer's Law by diluting your sample with 50% water, repeatedly.

Venture off into the unknown.

See Spectral Analysis Techniques for an overview of different kinds of spectrometry.

Read about sample preparation of liquids and solids, and what kinds of sample containers to use: http://publiclab.org/wiki/spectrometry-sampling