I first learned of this site from my subscription to NASA Tech Briefs.
They were reporting on a spectrophotometer (a device used to analyze the elements in a chemical sample).

Two students at the University of Illinois Champaign Urbana developed a simple working spectrophotometer using materials costing less than two dollars. (and a cell phone camera)
They developed software which is free to download which takes an image using a cell phone camera and the device you set up to analyze the sample.

As a physics project for a high school level this invention is awesome. Even better, since you build it yourself, you can learn the limitations of it and perhaps design your own improvements (like a light resistant enclosure.)

The system uses a diffraction grating (25 cents each), a cuvette (about 1 cent each), and a white LED, which can be bought from MPJA.com for 43 cents each.
The device is a cardboard frame to hold it all together which you cut out and mount the components in, and add a battery to drive the LED.

You shine the LED on the cuvette holding the sample and take a picture of the light through the diffraction grating. By running the picture through the software analysis program, it will analyze the sample and tell you what compounds/elements are in it.

This could be fantastic for high school chemistry classes and even for small hobby labs (my interest). Note that the design, plans, and software are all licensed as open source, meaning that they are free for your use. They run on Windows, Mac, and Linux.

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Sophie N. How neat. I'm sending it to my sister who's a teacher Thank you =)

4/13/11  •  Votes (1)

Jeremy G. I haven't seen a spectrophotometer since college! (well I may have run into a couple in grad school but no one would let me touch them at that point). Have you tried to build one? I like the idea of building things to better understand how they work, but I never had the patience (perhaps one of the many reasons why did not go to be an astrophysicist).

4/14/11  •  Votes (1)

mike h. The design looks simple enough, but I have been busy looking for work since I was laid off in the meltdown. When I get the time, I will build one. I already have almost all of the needed parts. Marlin P Jones MPJA.com has the LEDs and I got the diffraction gratings from American Science and Surplus. I still need to find the cuvettes.

4/15/11  •  Votes (1)