Leslie J. Lyons, Luther E. Erickson, Andrew Graham, Mark Levandoski, Martin Minelli, Elaine Marzluff,, T. Andrew Mobley, Corasi Ortiz, Lee Sharpe, Stephen Sieck and Elizabeth Trimmer Department of Chemistry Grinnell College Grinnell, IA Contextual and Active Learning in the Introductory Analytical Course: The Water Module

Context A fairly standard course that is the second course in the chemistry curriculum and covers introductory analytical and inorganic chemistry A strong focus upon equilibrium and basic inorganic chemistry The Water Module Structure and Session Questions Content and Context Pedagogy (Active Learning and Group Work) Student Results on Drinking Waters

Learning Goals-Water Module Challenging concepts (coupled equilibria and electrochemistry) taught in a meaningful/relevant context on a ‘real’ sample (their water sample from home). Students review prior course material in a new context. Students compare their experimental results to water quality reports by communities and EPA regulations to connect their learning to the ‘real world.’ Their final oral presentations combine course content, experimental results and regulatory standards for their results.

Learning in a Context (Module): What’s in your water besides H 2 O? 5 weeks of lab; 4 weeks of class Question driven discussion of solubility equilibria, carbonate equilibria, atomic spectroscopy, and electrochemistry Lab analyses of drinking water from around the country with Grinnell, Chicago, Des Moines, and bottled water providing benchmarks Lab concludes with student poster or PowerPoint presentations

Water Module Analyses Total Dissolved Solids by Conductivity Ca 2+ and Mg 2+ by EDTA Titration pH, CO 3 2-, HCO 3 - by pH Titration Na + by Atomic Flame Emission Spectroscopy Cl - by Potentiometric Titration F - by Ion Selective Electrode NO 3 - by Ion Selective Electrode SO 4 2- by Anion Exchange Ion Chromatography

Lab Pedagogy: Jigsaw Groups Students specialize in an experiment. Students work to bring all their results together and see relationships between their experiments, the water source, water treatment, and EPA reports/standards. 24 students in 4 water groups

Water Module: Class Sessions (Week 1) Session 1. Formulating the Questions and Limiting the Exploration: Focus on Ionic Composition Session 2. Dissolved Ionic Solids: Which ionic salts are present in typical water samples and how did they get there? Session 3. Major species vs. minor species: Why are so many different concentration units employed to describe concentration levels of the several species present in water samples?

Water Module: Class Sessions (Week 2) Session 4. Carbon dioxide and dissolved carbonates: Why do virtually all fresh water samples contain bicarbonate as a principal species? Session 5. Hard water: What is meant by hard water and why does degree of hardness matter? Session 6. Sodium and yellow flames: How can we determine how much sodium is in the water?

Water Module: Class Sessions (Week 3) Session 7. Galvanic Cells and Ion Concentrations: How can galvanic cells be used to determine ion concentrations? Session 8. Potentiometric Titrations: How do ion concentrations change in the course of a titration? Session 9. Ion-Selective Electrodes and ppm Concentrations: How can we determine ion concentrations at the 1 ppm level?

Water Module: Class Sessions (Week 4) Session 10. Conservation of Mass and Charge: Does it all add up? (including presentation preparation) Session 11. What does it all mean? What does the complete chemical analysis reveal about the source and treatment of our water samples? Session 12. Exam

Some Water Samples and Some Analytical Results

Bottled Waters Natural Spring Waters Purified Waters

Total Dissolved Solids Sample Measurement on Grinnell tap water

Data from Phyllis Frimpong, Spring, 2012

Titrations: Ca 2+ and Mg 2+ MIn - (red) + HEDTA > HIn 2- (blue) + MEDTA 2-

Some Student Results

Data from Joo Young Yim, Spring 2012.

Chloride Potentiometric Titration Data from Alex Plemmons, Spring 2014

Ion Selective Electrodes Other Ion Selective Electrodes: pH (H + ), Nitrate (NO 3 - ) Fluoride Data from Ben Doehr, Spring, 2012

Nitrate in Iowa Waters

Atomic Emission Spectroscopy Grinnell Tap Water Data from Jack Adams, Spring, 2012

Water Module Student Data K. Brown, I. Bakhira, S.K. Lee, L. Eshun-Wilson, J. Lytle, Fall, 2013

Serena Hochareon, Spring ic_Works_Department/2012_Water_Quality_Report.pdfhttp:// ic_Works_Department/2012_Water_Quality_Report.pdf. Accessed April 22, 2014.

Flannery, Hackman, Hochareon, Li, Matson, Robinson, Spring, 2014

Conclusions Water Module has been a core part of the CHM 210 course for 15 years: taught by all faculty, in all sections of the course taught in both ‘workshop’ and ‘traditional’ formats Well received by students “labs were really fun” and “I particularly liked our Water Module project” student comments on end-of-course evaluation from Spring, 2014 “I loved Water Module lab.” student comment on end-of- course evaluation from Spring, 2012 “I am not a science major, and never thought I would take another science class at Grinnell, but I’m happy that I did. … I particularly found the water module beneficial and relevant to my academic interests.” student comment on end-of-course evaluation from Fall, 2008

Acknowledgements Luther Erickson, “ What’s in your water besides H 2 O?: A Drinking Water Analysis Module for CHM 210,” Grinnell College, The chemistry faculty who have taught CHM 210/130 and the water module in the past: Filinger, Graham, Levandoski, Lyons, Marzluff, Minelli, Mobley, Ortiz, Sharpe, Sieck, and Trimmer. The entire faculty of the chemistry department who have attended water module poster presentations for many years. Over 400 CHM 130/210 students whose data are reported here. Mike Princer and Annie Campbell who support the 210 labs and classes.