In my class, I use the illustration of a mountain to help students push through the challenges of chemistry. Stoichiometry is the top of chemistry mountain. As we progress through the year, I say things like “the mountain is getting steep here!” or “there is not a lot of oxygen up here!” or “I will carry you up chemistry mountain if I have to!” to keep students motivated. When students finally get to the top of chemistry mountain (mid quarter 3), the air is thin, they are tired and they are ready to base jump off the mountain (see illustration from a former student below).
Show the kids an event. Have them develop a model. Have each kid draw and write about the model and force them to ask themselves if this model can explain the event. As a teacher, first say something nice about it and then look for their misconceptions and use this as a formative assessment. Combine the individual models with others. Slowly build a larger model and constantly ask if this really explains the event.
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.