The purpose of a lab practicum is to assess a student’s understanding of the content by completing a hands-on challenge. These assessments focus more on problem-solving skills than technique.
I started teaching in a chronological order when I began using Modeling Instruction in my classroom. During the second year of "walking in the footprints of the scientists that came before us", I wanted my students to see where they were walking and a colleague and I came up with the idea of making footprints for each of those scientists and posting them on a timeline.
It was the empty terrible feeling in the pit of my stomach at 9:30 at night that really bothered me as I am wading through the stack of papers that I was grading. I had the students do experiments, worksheets, I lectured and there was homework. Some of the students could “do” what I thought was science. They could calculate the answer. They could balance the equation.
Like most chemistry teachers, one of the first things I go over in the beginning of the year is unit conversions. Students come into my class with all sorts of prior knowledge concerning unit conversions; some good, some bad and some downright ugly.
Stoichiometry is arguably one of the most difficult concepts for students to grasp in a general chemistry class. Stoichiometry requires students to synthesize their knowledge of moles, balanced equations and proportional reasoning to describe a process that is too small to see. Many times teachers default to an algorithmic approach to solving stoichiometry problems, which may prevent students from gaining a full conceptual understanding of the reaction they are describing.
As school districts across the country approach the implementation of the Next Generation Science Standards, students will be required to develop models to illustrate what occurs at an atomic level as well as apply various mathematical representations in order to explain a science-based concept. However, what opportunities are we providing our students to allow them to explain what they know about a concept? Students should be provided with regular opportunities to develop and explain concepts, which in turn will allow teachers to formatively assess and address misconceptions.
Anyone interested in learning more about Modeling Instruction in Chemistry can find out more about it by attending any of the several presentations or workshops at ChemEd 2015. Here is a list of sessions and a summary of each.
I started thinking about how integral the storytelling was to the curricular choices I made in my classroom. I realized that I had shared some of my experiences as a Modeler and a few of the activities we use in our classrooms, but I have never described the order of topics. So, this blog is titled “The Model So Far…” I hope it gives you an idea of the journey we take each year as the students uncover evidence and construct models along the way.
Every year when the day came to discuss the rules for significant figures in measurements with my classes I would write the rules on the board, we’d work through a couple examples, and I’d try to find a way to explain why we needed to use them when reporting measurements. This has never been my favorite topic to teach, mostly because I had a difficult time helping students see why these rules for measurement and reporting uncertainty were important.