You can find the evidence statements at this link http://www.nextgenscience.org/middle-school-evidence-statements
When we looked at the evidence statements for MS-PS1-2, we found validation. We found that that we had prepared students to achieve proficiency. We had given students many opportunities to analyze data from before and after a change to determine if a chemical reaction had occurred. In doing so, we also required them to provide evidence to support their ideas.
However, when we looked at the evidence statements for MS-PS1-5, we realized that we had missed a few key details for this performance expectation. We had students creating models to show the before and after of a chemical reaction. We had students counting atoms in the before and after models to show that the number of atoms remains the same while the arrangement of atoms changes. However, we had failed to help students understand that each type of atom has a specific mass that stays the same.
After this realization, I decided to use students as human models of a chemical reaction. The same students generated the reactants and the products so that students could visibly see that the "atoms" had the same mass before and after the reaction.
As we move throughout the rest of the year, we'll be using the evidence statements as part of our curriculum design. As we do, we'll be keeping these things in mind (from the Introduction and Overview of the evidence statements).
- Evidence statements are not curriculum
- Evidence statements define the floor (minimum proficiency) and not the ceiling of achievement
- All components of an evidence statement should be visible for a student's work to be considered proficient.