Who does science? What is a scientist? What does a scientist look like?
These are common questions we often ask our students at the start of the year – these prompts can get kids thinking about their perceptions of science and can be quite revealing. Often the case is that kids have an image of someone like Bill Nye in their minds – white men in lab coats, doing complicated experiments in labs. Many of our students don’t see themselves as having the skills required to participate in authentic scientific research. Additionally, we often find ourselves as teachers feeling ill-equipped to undertake research without the technology, lab resources and other specialized equipment that our schools often lack. A different approach to scientific research, undertaken by citizens, is crucial for our students, communities and the larger society as we take on the global challenges we all face right now.
Throughout the history of the world, most science has been done by regular people as they observe, question, try out ideas and make mistakes that lead to discoveries. We want to show students that science is something they can participate in as interested, concerned, autonomous thinkers and citizens. In order to do this effectively, we need to provide our students with authentic learning opportunities in our local school environments. When students have the chance to study real problems in their own communities, generate solutions and present them to a real audience, we are putting science back into their hands and empowering them to become agents for change.
The farmers in the chinampas are facing one of these very real problems in their community and we had the opportunity to learn the very accessible technique that REDES is using to help them address it: chromatography.
The prevalence of pollutants in the chinampas adversely affects the quality of the soil and the health of the plants grown there. Chromatography makes it possible for the farmers to see a snapshot of the soil condition in their own chinampas and determine what they can do to improve it.
To begin, several soil samples are collected from different areas in an individual farmer’s chinampa using small gardening shovels. The soil samples are then spread into thin layers on butcher paper and left to dry for a day or two.
Next, each sample is sieved and ground to a fine dust using a mortar and pestle. The goal of this grinding is to ensure adequate mixing during the following step of the process, in which the soil is mixed with sodium hydroxide. The solution is left to sit and mixed three times over the course of 8 hours.
In the meantime, filter paper is prepared to receive the sample, making up both the medium for exposure and the wick to transfer the solution to the medium. The wick is placed in a small amount of silver nitrate that is absorbed into the circle-shaped filter.
When the soil solution is ready, a small amount is extracted with a syringe and placed in a dish. The solution is then transferred to the filter paper in the same way as the silver nitrate. Then, all that’s left to do is wait. Over the next two weeks, a pattern will develop (see “Field Protocols” post) that can be interpreted to understand the quality of the soil in that particular location.
What makes the chromatography technique so exciting is that it has the potential to be an empowering tool for farmers, putting science into their own hands.
As far as testing techniques go it is simple, requiring a minimal amount of affordable components: two chemical solutions, filter paper, a couple of petri dishes (or even bottle caps!), and a syringe. It is also a qualitative measurement – the process yields an interpretable image that farmers can compare against other chroma to gauge the relative health of their soil and then make decisions based on these results. This format is more accessible than quantitative soil data that requires formal training and prior knowledge to interpret.
When we were performing the technique ourselves many of us had questions about the very specific mixing technique – “Spin the solution 6 times to the left and 6 times to the right. Do this 6 times”. Yolo, the scientist who trained us in this process, explained to us that this protocol serves a number of purposes that exemplify how accessible this process is. Not only does this protocol ensure adequate mixing without lab equipment, it also standardizes the process and reduces field variables. Most importantly, it’s easy to remember.
Chromatography can bring farmers into a true scientific community. While it has been proven to be an effective way to demonstrate soil health, the chromatography technique is burgeoning and still not fully understood. Yolo has also been working to increase the base of knowledge of the underlying meaning of the chromatography images in the form of a public database. As farmers perform this technique for their own chinampa, they can utilize this database as a resource for interpreting their chromatography and can also submit their own results.
The farmers in the chinampas are facing a crisis. Together, with the researchers at REDES they are taking this on using science that is accessible and immediately useful. This should inspire all of us, teachers and students, that it is citizens who are solving the problems facing our society. In the face of seemingly insurmountable environmental challenges, we can all use science to be a part of the solution.
Jessie, Jamie, and Katie