You’re in a parking lot and you look down at a puddle with some rainbow-looking residue in it. What could it be? Or maybe you are at the beach, and you see some interesting substance on the ground, but you have no idea what it is. Well, now you just might be able to examine exactly what is composing those spilled chemicals – or pollution. A group involved with the Public Lab created an open source project that enables environmental engineers or curious minds to go out into the environment and test what contaminants we as humans leave behind. The experiment can determine exactly what kind of oil is polluting an area, whether it is crude oil, motor oil, heating oil, or other petroleum-based contaminant. You can check out the video on just what it does below.
The experiment uses a spectrometer to determine which contaminants compose the pollutant. Each molecule of oil fluoresces (glows) at a different wavelength, giving them each a specific colour and allowing you to determine the composition with a spectrometer. The experiment is a fun and informative way you can learn about the environment and its compositions around you.
The experiment calls for:
– protective latex or nitrile gloves
– cotton swabs
– some small glass bottles, like empty nail polish bottles, or plastic cuvettes (available on Amazon)
– mineral oil (from the pharmacy — it’s used as a laxative; also sold as “baby oil”)
– a “Blu-Ray” or 405 nanometer laser
a spectrometer: you can build one from a piece of DVD-R, a webcam, and a light-sealed box. Instructions and design files for several types can be found on the Public Lab website, this Instructable also covers the use of a spectrometer to do a specific type of analysis.
Most of the materials used will need to be sealed in a plastic bag and properly disposed of since they will come into contact with the potentially hazardous chemicals you will collect off of the ground- so try not to use your grandparents eye drops, they may not be so pleased…
A more detailed list plus links including where to buy the materials can be found at the bottom of the Public Lab Oil Testing Kit page.
Collect, Scan, & Compare
The process for testing oils can be summarized in three overall steps;
1. Collecting samples of suspected oil or tar from the ground, and dissolving small amounts in mineral oil so they are transparent
2. Illuminating the solutions with ultraviolet light — presently using a 405-nanometer blue laser — and recording the light spectrum with a DIY spectrometer, as shown in the diagram above
3. Comparing the spectrum to those of similarly prepared samples of known pollutant oils, as well as a negative control
An updated version of the lab can be found at the Oil Testing Kit page on the Public Lab Wiki.
First, you will need a spectrometer. A spectrometer is basically a device that is used to differentiate the different colours specific chemicals will produce, allowing you to determine what kind of substance you have. You can purchase one (they are not very expensive) or you can build one yourself, the open source DIY or purchase link can be found if you follow this link to the Public Lab website. You can check out what it will look like below
[Image Source: Public Lab]
The spectrometer is connected to the computer so when you shine the laser through it, it will be able to analyze and determine exactly what you are dealing with- some truly fascinating technology! Of course, all the source code is open sourced and is included with the instructable above.
And don’t worry, your spectrometer will be usable in other areas of analysis including
– detection of brightening agents in laundry: /n/174
– pesticides: /n/10015
– sugar in red wine: /n/10955
– olive oil adulterants: /n/10382
– milkfat concentration: /n/10012
– lycopene in tomatoes: /n/9432
– atmospheric spectra: /n/6168
– concentration analysis (Beer’s Law): /n/7475
– flame spectroscopy: /n/4406
– importing reference spectra: /n/8995
Next, you will need to attach an oil analysis section to the spectrometer. This will house the contaminants and enable you to scan what you have. Follow the link to the Public Lab Oil Testing Kit to learn how to make your own, or to buy one ready made (still inexpensive).
Oil testing kit [Image Source: Public Lab]
Now comes the fun where you get to put your new equipment to the test. The spectrometer and oil analysis kit can now be used to scan and use your computer to analyze the composition of chemicals that you discover. The instructions on how to analyze your contaminants can once again be found at Public Lab Oil Testing Kit webpage which includes all the instructions. Have fun examining pollutants and seeing what you can come up with!
[Image Source: Public Lab]
Now you can see for yourself exactly what is in the world around you with a bit of construction and some curiosity! A big thank you goes out to the creators at the Public Lab that made this open sourced project available to curious minds across the globe.