Katie Phalen is a chemistry teacher at Tempe High School, Tempe Union High School District in Tempe AZ. B.S. (Agriculture) University of Arizona. Ms. Phalen has been an educator for 25 years and is currently teaching HOPE Chemistry (Health Occupations Preparatory Education) and Introductory Chem-Physics. In the past, she has taught a wide range of courses including Honors Chemistry, General Chemistry, and Biology. She enjoyed developing the “Troubled Waters” lesson plan as it is designed to address the world water crisis from a chemical and biological stand point.