In a previous article, GREEN was given an insight into the changes taking place in the chemistry teaching laboratories at the University of Arizona. One exciting change was the implantation of the new “milli-scale” procedures in the new chemical thinking lab courses. This new approach incorporates revisions to experimental procedures as well as changes to equipment and analytical techniques. The greatest gain of these changes is to reduce waste while ensuring students can understand key concepts equivalent to those in a typical general chemistry lab.
The “milli” in the name corresponds, to a reduction not only in the amounts of chemicals used but also a reduction in the size of the glassware used. Using the new approach, students are working with an average of 0.1-10 mL of liquid chemicals whereas before they were operating in the range of 10-100 mL (or more). With reduced amounts of chemicals comes smaller glassware. From large beakers and flasks to small plastic vials, reducing size has many advantages. The new glassware being used has the immediate benefit of having a reduced cost; $40-50 beakers are replaced with vials that are a fraction of the price. Along with a lower initial cost, replacing lost or broken glassware is also more affordable. Smaller glassware also means that students have smaller amounts of chemicals at their benches, thereby, reducing waste produced by each student. Even maintenance costs have seen a decrease, as analytical balances need to be serviced less frequently ensuring greater precision over a longer period of time. Scale reduction is a great tool for eliminating waste. With the new “milli” approach the instructors overseeing these lab sections have seen the waste during the first semester reduced by 1/3 and by 1/5 in the second semester over the time that the “milli-scale“ scale approach has been implemented. As mentioned in my previous article, the cost of waste in these labs can reach over $1000/week, thus reduction on this scale leads to a great amount of money saved for the department. On the environmental side, less waste ensures that few chemicals end up in landfills or in the atmosphere after being incinerated (Chem151 Labware).
It was a great privilege to be allowed to walk through the chemical thinking labs as students were completing a biochemical experiment. My walk through began in the preparatory room where I was shown how important absorption spectroscopy has become to this new approach. Students are given tutorials and access to software that allows them to work with spectroscopic instrumentation, giving them a way to monitor and quantify results in reactions where physical markers are difficult to see at the small scale. After leaving the prep room I entered a lab where students were busy working on an experiment. The students were analyzing a substance using an Ultraviolet-Visible (UV-Vis) spectrometer and monitoring temperature. As the teaching assistants in two labs remarked, the students are very responsive to the new instrumentation and software.
However what had the most impact on me during the walkthrough was seeing the waste from the regular general chemistry labs. As I was exiting, I saw a cart loaded with over a dozen 10L buckets of liquid waste from one week, all from the laboratory using procedures typical to an introductory chemistry course. In that same time the “milli-scale” labs had only gone through six-10L buckets, proving that there is a significant decrease in waste. This difference in waste was also shown in how well organized and the cleanliness of the “milli scale” labs. With fewer chemicals to manage, students seemed to be handling everything with more care. Yet, changes between the traditional labs and the chemical thinking labs are subtle; students are performing different experiments on a smaller scale with different lab equipment while the teaching objectives remain the same. For some experiments the chemical thinking actually push students further than they would go in traditional lab courses. In one experiment, students are taught about neutral buoyancy and learn how they can use this property to determine the density of recycled plastics. These changes are still few in number but it is exciting to imagine the benefits that could come from all the changes the teaching-lab staff have in mind.
It is often difficult to implement all-encompassing changes, especially when everything from equipment, instrumentation, and procedures are changing. However the chemistry labs here at the University of Arizona have done an excellent job at minimizing waste and cost while still giving students a full laboratory experience. Students use many different types of spectroscopic instrumentation that still provide them the fundamentals that they need for further chemistry courses. Most importantly, these students are being conservative about the chemicals they are using and learning how to properly dispose of materials. They are creating fewer spills and are reducing the risks present in the laboratory. While the “milli-scale” approach does not give the students the exposure of scalability and the (sometimes) large variances in how reactions behave when the scale is increased, the main goal of an introductory laboratory course is just that – introduction. This new approach also introduces a new concept to the chemistry teaching labs; the awareness of the environment and the detrimental impact old practices can have on the environment.
I would again like to thank Mark Yanagihashi for providing a wealth of information and for taking the time to walk me through a lab.