living by chemistry: progress variables, learning progressions

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:

CH4 + 2O2 CO2 + 2H2O

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

A better way: the BEAR Assessment system

The 4 Building Blocks

Construct Map

Items

Measures ItemScores

Matter is composed of atoms arranged in various ways.

Change is associated with rearrangements of atoms.

Energy is associated with changes that occur.

PROGRESS VARIABLESLBC 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 reasoningnovice

expert

stud

ent

unde

rsta

ndin

gLevels 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.

C4H8O4

butyric acidC4H8O4

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

ChemQueryQuality evidence:To help ALL students increase understanding of chemistry

ss

s

s

s

s

s

s

s

ScoreLevels

Low Middle High

Pretest

Post-test

Fall 2000 Student Gains, Grouped by Pretest Score

2

-2

+1

1

-1

0

0

20

40

60

80

100

Notions Recognition Formulation Construction Generation

0 semesters2 semesters3 semesters

ChemQueryCriterion 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


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 observationssimple

complex

build

ing

mat

ter


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 irrelevantsimple

complex

reas

onin

gChemQuery

Criterion referenced assessments, tracking student learning

Atomic and molecular viewMass as evidence for atomic view

Rearrangements of atoms Conservation of mass

Quantum viewConservation of energy


To help ALL students increase understanding of high school chemistry

Living by Chemistry

5 Integratethe domain

4 PredictScientific models

3 RelatePatterns andEquations

2 RepresentScientificdefinitions

1 DescribeObservations& experience

0

ACharacterizing

MatterMatter is

composed of atoms arranged in various ways

BMeasuring

MatterMass is

used to accountfor matter

CCharacterizing

ChangeChange is

associated withrearrangements

of atoms

DQuantifying

ChangeMass is

used to keep track of change

EEvaluatingEnergies

Energy transfer used to analyze

tendency for change

FQuantizing

EnergyInteraction of

light with matter elucidates structure


Quantitative vs Qualitative

5 Integratethe domain

4PredictScientific models

3RelatePatterns andEquations

2RepresentScientificdefinitions

1DescribeObservations& experience

0 ACharacterizing

MatterMatter is

composed of atoms arranged in various ways

BMeasuring

MatterMass is

used to accountfor matter

CCharacterizing

ChangeChange is

associated withrearrangements

of atoms

DQuantifying

ChangeMass is

used to keep track of change

EEvaluatingEnergies

Energy transfer used to analyze

tendency for change

FQuantizing

EnergyInteraction of

light with matter elucidates structure

bonding &reactivityadvanced bonding models, nucleophiles, electrophiles

phase &compositionbond strengths, intermolecular

attractions, polarity

properties & atomic viewsoctet rule, ionic and covalent bonds

matter with chemical symbolselements, compounds,valence electrons, periodic trends

properties of mattersolids, liquids, gases, mixtures

models & evidenceevidence about things we can’t observe directly

limitations of modelsexamining evidence

assumptions

measured amountsof matterdensity, grams permole,molarity

mass with a particulate viewatoms, isotopes, moles

amounts of mattermass, weight, volume, pressure

kinetics &changes in bondingrxn mechanisms, activation energy

products of reactionsolubilities, relative acid strengths

change &reaction typesprecipitation, acid-base, redox

change with chemical symbolsbalanced equations, phys,vs chem change

attributes of changemixing, dissolving, color change,change in form

stoichiometry & equilibriumweak acids &bases, solubility of salts, gases

amounts ofproductslimiting reagents,strong acid/base titrations, % yield

amounts ofreactants & productsreaction stoichiometry, pH

change with a conservation viewconservation of mass inchemical reactions

changes in amountchanges in mass,weight, volume

particle & energy viewsstatisical mechanics KE & temperature

degrees of changeentropy, free energy & equilibrium

energy transfer& changeenthalpy changes Hess’s law, bond breaking

heats &temperatureheat capacity,calorimetry,exo(endo)thermic

measures of energytemperature, scalesmeasures of energy

spectroscopy & structuregroup theory, transition probabilities

electronic structurequantum model,atomic & molecular orbitals, ionization energy

color with light absorptionabsorption &emission spectra

energies associatedwith lightfrequency, speed, Planck’s constant

lightproduction 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.



Student levels of understanding Matter Change

III. Formulation

II. RecognitionAtomic symbols,

octet ruleChemical equations,

conservation of mass

(atoms/stuff/grams)

I. Notions Solid, liquid, gas Stuff happens

macro

particulate

conservation

number

molemass


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


Final Thoughts

living by chemistry: progress variables, learning progressions

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