Tuesday, July 17, 2012

#ModChem Day 6

Modeler's Log, Day 6--

The second week started off with just as much energy as the first.

We started off with a hearty discussion of Testing for Conceptual Understanding in General Chemistry by Craig W. Bowen and Diane Bunce. This was perhaps our best article-based discussion thus far in the workshop. The article dealt with misconceptions in chemistry that have been elucidated by a number of researchers on the topic as well as assessment strategies to address misconceptions.
We were prompted to decide how we will change our assessments in the future to reflect our knowledge of misconceptions. There was a tremendous exchane in which participants discussed many great ideas, including:
  • Assessments for measuring individual progress (summative assessments and formative assessments) vs. measuring whole group progress (Modeling chemistry's Assessment of Basic Chemistry Concepts, ABCC) 
  • Paired or linked questions (like on the ABCC) or the sets of questions where the second question depends on answer to first 
  • Open-ended constructed response questions instead of mere multiple choice questions 
  • Conceptual questions vs. algorithmic questions 
  • To allow/permit test-corrections or reassessments and the value of learning from mistakes on tests 
  • Writing "good" or plausible distractors that address different misconceived lines of thinking and rules of assessment question writing 
  • Test questions often ask for critical thinking from students, but if teachers don't provide opportunities for students to practice critical thinking during class, then the assessment isn't fair 
  • When we "teach" something in class and then assess something similar, but only to find that the students weren't able to do it, we as educators conclude: "the students weren't able to do..." instead of "what did I the teacher do that led to this?" 
  • Do conceptual questions or explanatory open-ended and constructed response questions "hurt" students who have language issues? 
  • In the "real world," people have resources and life-lines, why don't we provide those parameters more in a classroom assessment setting? 
  • Teaching to a test vs. teaching to standards (when to create/generate your assessment: before teaching or after teaching?)
After this rich discussion, we moved on to a lab--the most EXCITING lab of the year--the water heating curve lab.We took some ice in a beaker and heated it through changes of state and temperature changes until it boiled. This lab took quite some time, but since we had so much fun doing it, we forgot about the time. 

Here is the lab, condensed in to about a minute and a half through stop-motion animation video:

After debriefing the lab on the heating of water through temperature and phase changes, we arrived at a representation for the energy storage and transfer in in the system that represented the changes that were taking place. We were able to infer that though energy was constantly being transferred from the hot plate to the water in the beaker, when the temperature wasn't changing the energy was still being transferred somewhere. The destination of the energy transfer was the distance between the particles (the arrangement of the particles) represented by the Eph, or energy of phase. This was contrasted by the regions of the curve where there was a temperature change, and in that case we recognized that the energy was being transferred to the energy associated with the particles' motion (thermal energy.) 

Our exploration into energy transfers and storage moved from there to constructing a representation of the storage and transfer of energy using bar graphs, fondly referred to as "LOL" diagrams. These diagrams provide students a visual way to describe the energy stored in a system and transferred between a system and its surroundings. This handy and cognitive way of representing energy prevents energy from being vague to students and provides a way for them to think through situations and problems involving energy quantification and transfer.

Once we had a way to represent energy, it was on to represent the energy storage and transfer in the heating of water experiment using bar charts. The LOL diagrams were connected to points on the heat curve and this allowed us to see what was happening with the energy, more transparently, during the different stages of the heating of water. For some background on the treatment of energy in the modeling approach, see Larry Dukerich's presentation on a coherent treatment of energy.

After learning how to treat energy in different situations, we deployed our model for representing energy storage and transfer on the corresponding unit homework worksheets. Then, we whiteboarded and discussed some problems and their solutions. By the end, we had a pretty strong understanding of how to represent energy in a variety of settings.

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