A spectrometer is an instrument that can be used to identify substances based on how they interact with light. The tool can display a light pattern that is unique to different compounds, making them ideal for comparisons with cataloged spectra to identify the chemical composition of unknowns. Traditionally, lab spectrometers in a high school physics or chemistry class are fairly rare due to their expense and somewhat delicate nature. Benchtop lab spectrometers are heavy and cumbersome to move around, and hand held units are extremely expensive and may not be able to be secured due to their portable nature. This is a missed opportunity because there are many applications for testing unknown chemicals as well as learning about why substances behave the way they do if their constituents could only be identified in the classroom.
Enter the open source movement and the cheap laptop computer. There are too many examples of how open source software has made STEM education much more accessible to students to cite here, but now integrating inexpensive hardware with software can make your STEM students into real scientists. The great thing about cheap laptops and tablets available today is the way in which clever software and sensor design can take advantage of the computational power of these devices to turn them into instruments that were once the exclusive purview of private laboratories and universities. A corollary worth mentioning is the advent of microcontrollers such as the arduino and raspberry pi that can do the same thing at an even lower cost, but the focus for the moment is on the laptop spectrometer.
A concern known as Public Laboratory has gone a step further to democratize instrumentation (and science in general) by introducing several open source DIY (kits are available too) versions of scientific tools. The hardware and software are both open source designs, which means they are accessible and inexpensive (or free) but are under constant development from the community-so expect relatively rapid changes. The Spectral Workbench software works in your internet browser making it easy to upload data to the spectralworkbench.org site. The data is obtained by scanning samples with the spectrometer your students build. The kit of parts basically consists of commonly available items such as an HD webcam, A conduit box, a piece of black card stock and a segment of an old dvd-r. You can get a .pdf of the build instructions here so take a look.
What is really nice about this process from start to finish is how it integrates the construction and use of the spectrometer to actual science. Your STEM student’s experiments can be used to contribute to the growing database of scanned materials uploaded to the spectralworkbench.org site, helping to identify all sorts of materials by looking at their spectral images. A wide variety of materials have already been categorized, and there are an unlimited number of applications for students to participate through any number different STEM projects, from environmental science to physics. So we see the collaborative efforts extending from the creation of these open source products to the students who use them as they share their data online.
The advent of cheap, accurate and easy to use instruments for schools is just beginning. Public Laboratory is currently working on a spectrometer that attaches to your smart phone, which means something very exciting is going to happen before this year’s freshmen graduate high schoool: everyone, everywhere, can soon gather and share data like a real scientist, simply with what they already carry in their pocket.