In High School Chem Labs, Every Camera Phone Can Be A Spectrometer

University of Illinois chemistry professor Alexander Scheeline has developed software that turns a camera phone, an LED, and a few other cheap tools into a spectrometer. Armed with these, he thinks we can bring high-end analytic tools to high school chemistry labs all over the world.

“The potential is here to make analytical chemistry a subject for the masses rather than something that is only done by specialists,” Scheeline said. “There’s no doubt that getting the cost of equipment down to the point where more people can afford them in the education system is a boon for everybody.”

Purpose-built spectrophotometers are essential tools in analytic chemistry. By measuring the electromagnetic spectrum a substance absorbs or emits, you can determine its molecular composition. They’re also expensive, which is why they’ve generally been confined to universities. Scheeline has already brought his cell-phone spectrometers to high schools in Atlanta and Hanoi. Other high-school chemistry and physics teachers doing professional development at Illinois have also brought Scheeline’s tools to their classrooms.

Initially, Scheeline hadn’t been looking for ways for students to use their phones in class. Instead, he wanted students to build their own spectrophotometry tool, to better understand their instruments and their limitations. Putting together the LED as a light source, diffraction gratings and cuvettes were easy; finding a small sensor to capture the light was hard.

“All of a sudden this light bulb went off in my head: a photodetector that everybody already has! Almost everybody has a cell phone, and almost all phones have a camera,“ Scheeline said. “I realized, if you can get the picture into the computer, it’s only software that keeps you from building a cheap spectrophotometer.”

Scheeline with the analysis software he's developed for the cell-phone spectrometer.

Scheeline wrote a Windows desktop program to analyze the student’s JPEG files from their phones. One advantage of this approach over developing a smartphone application to do the analysis directly: because the phones are used only to take the photographs, it doesn’t matter what kind what operating system a student’s phone is running.

 

Scheeline then published his source code, a compiled executable application and the cell-phone spectrometer instructions for anyone to download from the Analytical Sciences Digital Library. He also published an article on the device and its potential in chemistry education in the academic journal Applied Spectroscopy.

“Science is basically about using your senses to see things – it’s just that we’ve got so much technology that now it’s all hidden,” Scheeline said. “The student gets the impression that a measurement is something that goes on inside a box and it’s completely inaccessible, not understandable – the purview of expert engineers.”

“In order to get across the idea, ‘I can do it, and I can see it, and I can understand it,’ they’ve got to build the instrument themselves,” he added.

Can you analyze me now? Cell phones bring spectroscopy to the classroom [University of Illinois]

All images by L. Brian Stauffer via news.illinois.edu