Living by Chemistry: Progress Variables, Learning Progressions Karen Draney University of California, Berkeley

LBC started with the following observation: Students who can write this equation for combustion: CH 4 + 2O 2 CO 2 + 2H 2 O often cannot answer: "When a house burns to the ground and only a few pieces of charred wood and ashes are left, what happens to the rest of the mass of the house?” (AAAS Project 2061 conference 2001)

How to define understanding of chemistry? “Chemistry” A typical “laundry list” of topics: Stoichiometry Atoms and elements The periodic table Chemical bonding Molecular structure Physical and chemical change Acid-base equilibrium Oxidation-reduction reactions Thermodynamics Chemical kinetics.....Solubility......…etc....etc...etc.... Student understanding?

Decide on variables to measure learning outcomes Define a scale to quantify the variables Design an instrument to determine the values of the variables for individual students Applying criterion-referenced measurements to characterize student understanding. BEAR Assessment System A better way: the BEAR Assessment system

The 4 Building Blocks

Matter is composed of atoms arranged in various ways. Change is associated with rearrangements of atoms. Energy is associated with changes that occur. PROGRESS VARIABLES LBC Curriculum and ChemQuery Assessment

5 Generation: Research 4 Construction: Examining assumptions, relating models 3 Formulation: Relating ideas and concepts, simple models 2 Recognition: Language, definitions, symbols algorithms 1 Notions: Everyday experience, logical reasoning novice expert student understanding Levels of Progress: Focus on Student Understanding

ChemQuery Examples of items: Both of the solutions have the same molecular formulas, but butyric acid smells bad and putrid while ethyl acetate smells good and sweet. Explain why these two solutions smell differently. C 4 H 8 O 4 butyric acid C 4 H 8 O 4 ethyl acetate Items Design

ChemQuery Level One: Notions Response 1: I think there could be a lot of different reasons as to why the two solutions smell differently. One could be that they're different ages, and one has gone bad or is older which changed the smell. Response 2: Using chemistry theories, I don't have the faintest idea, but using common knowledge I will say that the producers of the ethyl products add smell to them so that you can tell them apart. Response 3: Just because they have the same molecular formula doesn't mean they are the same substance. Like different races of people: black people, white people. Maybe made of the same stuff but look different.

Level Two: Recognition Response: "They smell differently b/c even though they have the same molecular formula, they have different structural formulas with different arrangements and patterns.” ChemQuery

Quality evidence: student profile

Quality evidence: track student over time

ChemQuery Quality evidence: To help ALL students increase understanding of chemistry ss s Score Levels Low Middle High Pretest Post-test Fall 2000 Student Gains, Grouped by Pretest Score

ChemQuery Criterion referenced assessments, tracking student learning High School and College Students

Creating a Construct Variables Main topics (chapters or subdisciplines) Models or theories Popular understanding Levels of progression A little of x, more of x, a great deal of x Complexity: A, A+B, A+B+C, A+B+C+D Range vs hierarchy

Macroscopic phenomena can be described by the positions and motions of electrons atoms and molecules Mass and energy are conserved in chemical reactions The tendency for physical or chemical change can be predicted by comparing relative reactivities for various substances Big Ideas of Chemistry: Round 1 ChemQuery Criterion referenced assessments, tracking student learning

5 Integration across variables 4 Bonding (ionic, covalent molecules, perhaps collections of molecules 3 Model of the atom (including elements and periodicity 2 Particulate view (definition of matter as particulate) 1 Macroscopic observations simple complex building matter ChemQuery Criterion referenced assessments, tracking student learning

4 Explaining Molecular Behavior: Explains molecular behavior and properties in terms of stability and energies 3 Examining Structure-Property Relationships: Recognizes that matter has characteristic properties due to the arrangement of atoms 2 Representing Matter: Explores meaning of words, symbols and definitions to represent matter 1 Describing Properties of Matter: Describes materials observed with senses, uses logical patterns 0 Prestructural: Response is irrelevant simple complex reasoning ChemQuery Criterion referenced assessments, tracking student learning

Atomic and molecular view Mass as evidence for atomic view Rearrangements of atoms Conservation of mass Quantum view Conservation of energy Big Ideas of Chemistry: Round 2 To help ALL students increase understanding of high school chemistry Living by Chemistry

5 Integrate the domain 4 Predict Scientific models 3 Relate Patterns and Equations 2 Represent Scientific definitions 1 Describe Observations & experience 0 A Characterizing Matter Matter is composed of atoms arranged in various ways B Measuring Matter Mass is used to account for matter C Characterizing Change Change is associated with rearrangements of atoms D Quantifying Change Mass is used to keep track of change E Evaluating Energies Energy transfer used to analyze tendency for change F Quantizing Energy Interaction of light with matter elucidates structure ChemQuery Criterion referenced assessments, tracking student learning Quantitative vs Qualitative

5 Integrate the domain 4 Predict Scientific models 3 Relate Patterns and Equations 2 Represent Scientific definitions 1 Describe Observations & experience 0 A Characterizing Matter Matter is composed of atoms arranged in various ways B Measuring Matter Mass is used to account for matter C Characterizing Change Change is associated with rearrangements of atoms D Quantifying Change Mass is used to keep track of change E Evaluating Energies Energy transfer used to analyze tendency for change F Quantizing Energy Interaction of light with matter elucidates structure bonding & reactivity advanced bonding models, nucleophiles, electrophiles phase & composition bond strengths, intermolecular attractions, polarity properties & atomic views octet rule, ionic and covalent bonds matter with chemical symbols elements, compounds, valence electrons, periodic trends properties of matter solids, liquids, gases, mixtures models & evidence evidence about things we can’t observe directly limitations of models examining evidence assumptions measured amounts of matter density, grams per mole,molarity mass with a particulate view atoms, isotopes, moles amounts of matter mass, weight, volume, pressure kinetics & changes in bonding rxn mechanisms, activation energy products of reaction solubilities, relative acid strengths change & reaction types precipitation, acid-base, redox change with chemical symbols balanced equations, phys, vs chem change attributes of change mixing, dissolving, color change, change in form stoichiometry & equilibrium weak acids & bases, solubility of salts, gases amounts of products limiting reagents, strong acid/base titrations, % yield amounts of reactants & products reaction stoichiometry, pH change with a conservation view conservation of mass in chemical reactions changes in amount changes in mass, weight, volume particle & energy views statisical mechanics KE & temperature degrees of change entropy, free energy & equilibrium energy transfer & change enthalpy changes Hess’s law, bond breaking heats & temperature heat capacity, calorimetry, exo(endo)thermic measures of energy temperature, scales measures of energy spectroscopy & structure group theory, transition probabilities electronic structure quantum model, atomic & molecular orbitals, ionization energy color with light absorption absorption & emission spectra energies associated with light frequency, speed, Planck’s constant light production of light, color

Matter is composed of atoms arranged in various ways. Change is associated with rearrangements of atoms. Energy is associated with changes that occur. ChemQuery Criterion referenced assessments, tracking student learning Big Ideas of Chemistry: Round 3

Student levels of understanding MatterChange III. Formulation II. Recognition Atomic symbols, octet rule Chemical equations, conservation of mass (atoms/stuff/grams) I. Notions Solid, liquid, gasStuff happens macro particulate conservation number mole mass ChemQuery Criterion referenced assessments, tracking student learning ChemQuery Construct

Don’t do this alone Iterative by nature All variables can start out simple Track student understanding from high school to graduate school ChemQuery Criterion referenced assessments, tracking student learning Final Thoughts