Conceptual Understanding versus

Algorithmic Learning

Margaret Asirvatham and Thomas Pentecost

Chemistry & Biochemistry

TIGER Presentation

January 24, 2008

Chemical Education Research

• Many novice learners tend to apply algorithms without significant conceptual understanding that must be developed for students to be successful problem-solvers.

• Chemistry problems are challenging as they may be expressed in different ways - symbolically, at the particulate (atomic/molecular) level, or at the macroscopic level.

Limiting Reactant: Lecture DemoInteractive Engagement

Mg(s) + 2 HCl(aq) MgCl2(aq) + H2(g)Flask # Moles of Mg(s) Moles of HCl(aq)Flask 1 0.0125 0.1000Flask 2 0.0250 0.1000Flask 3 0.0500 0.1000Flask 4 0.1000 0.1000What will be the relative sizes of balloons above the flasks when the reaction is complete?

A) V1 = V2 = V3 = V4

B) V1 < V2 < V3 < V4

C) V1 < V2 < V3 = V4

D) V1 < V2 = V3 < V4

E) V1 < V2 = V3 = V4

Colors represent three different lecture sections taught by the same instructor.

Limiting Reactant: Atomic/Molecular View

The diagram represents a mixture of S atoms and O2 molecules in a closed container.

Which diagram shows the results after the mixture reacts as completely as possible according to the balanced equation:

2S + 3O2  2SO3

(a) (b) (c) (d) (e)

Only 15% of the students (Spring 2006) selected the correct answer (d) after a whole semester of Gen Chem 1!

Fall 2006 (Pre) 10.5% correct; (Post) 41.8%

http://jchemed.chem.wisc.edu

S atom

O2 molecule

Can our students interpret atomic/molecular view

representations?H2O(s) H2O(l) 2H2O(l) 2H2(g) + O2(g)

Acknowledgment: Silberberg’s “Chemistry: The Molecular Nature of Matter and Change”

General Chemistry ConceptsExam 1 Question, Fall 2006

Examine the molecular views presented below:

Which of these represents a pure compound?

A) I (601) B) II (11) C) III (1) D) IV (179)

I I I I VI I I

General Chemistry Concepts Final Exam Question, Fall 2006

Which of these atomic/molecular views represent pure substances?

A) I and III (1) B) II and IV (55)

C) I, II and IV (616) D) II, III, and IV (7)

I I I I I I I V

General Chemistry ConceptsExam 1 Question, Fall 2006

Consider the molecular views of reactants as they are converted to products in the boxes shown below:

Which of these best represents the balanced equation for this reaction? A) NO + Cl2 Cl2NO (69) B) 2NO + Cl2 2ClNO (677)C) N2 + O2 + Cl2 2ClNO (3) D) NO + Cl ClNO (43)

chlorine

nitrogen

oxygen

General Chemistry ConceptsExam 1 Question, Fall 2006

Examine the molecular view of the chemical reaction between AB and B2 in the gas phase:

Select the correct statement about this reaction.

A) The balanced equation for the reaction is AB + B2 AB3. (23)

B) AB and B2 are present in stoichiometric amounts at the start of the reaction. (131)

C) AB is the limiting reactant. (615)

D) The product of the reaction is A2B. (23)

Meta-communication

“The most powerful tool for changing students’ attitudes about learning and enlisting them as active collaborators in their own education is meta-communication high level communication about the nature and purpose of the “normal communication” within the course.”

I.Beatty, “Transforming Student Learning with Classroom Communication Systems,” EduCause Research Bulletin, Volume 2004, Issue 3, February 2003, p. 11.

Meta-communication“Meta-communication can and should address the learning objectives of the course and its components, the virtues of instructional techniques and styles employed, and the reasons why particular assignments are given. Experience shows that students are far more cooperative when they understand why they are being asked to do something.”

I.Beatty, “Transforming Student Learning with Classroom Communication Systems,” EduCause Research Bulletin, Volume 2004, Issue 3, February 2003, p. 11.

Cubic Unit Cells

Acknowledgment: Silberberg’s “Chemistry: The Molecular Nature of Matter and Change”

Consider an atom in the simple cubic crystal lattice. What is the maximum number of unit cells that share this atom in the three-dimensional structure?

A) 2B) 4C) 6D) 8E) 12

Before After

Solid State: Cubic SystemsUsing New Lecture Demo Models

Number of Unit Cells that share a Corner Atom in the Simple Cubic Crystal Lattice

0

20

40

60

80

100

120

A B C D E

Percent Responses

Series1

Series2

Series3

Number of unit cells that share a corner atom in the simple cubic crystal lattice

0

5

10

15

20

25

30

35

40

45

A B C D

Percent Responses

Cubic Unit Cells

Simple Cubic Crystal Lattice

Lessons Learned

• Atomic/molecular visualization skills must be developed and reinforced

• Formative assessment with clickers and peer collaboration in large lecture classes

• Conceptual questions must be developed to address higher-order thinking skills as well as common misconceptions

• Integration of real-world context and effective lecture demonstrations are essential

Solutions

Chemistry Concept Challenges F06/Sp07

• Series of assignments developed to:• Think in terms of “atoms and molecules” (and ions)

• Make connections among macroscopic observations, symbolic representations, and what’s happening on the particulate level

• Use, interpret, produce, and translate among various representations in chemistry (words, symbols, particulate-level representations, mathematical relationships, graphs)

• Articulate their understanding

• Relate chemistry to the “real world”

• Make connections among several chemistry concepts

Examples:

• Representations of Matter

• Reactions in Solutions

• Gases

Recitation Workshops F07/Sp08

• Background– CHEM 1111 & 1131 5 credits

• 3 hrs/week lecture• 4 hrs/week recitation/lab

• Incorporate CCCQ materials into recitation sessions.– Allows materials to be used in a group work environment.– Allows us to follow physics workshop model.– Removes grading burden from TAs.

Recitation Materials

• Merged CCCQ materials with existing materials (algorithmic problems)

• Some CCCQ materials became pre or post laboratory questions.

• Some new materials written.

Ex: Thermochemistry

Implementation

• To implement this model for recitation needed to train TAs to facilitate.

• Before fall semester 2007 - three day training for new graduate students that were likely to teach CHEM 1111 that term.

TA Training

• Three days (Wed - Fri)• ~ 1.5 days on Chemical Education Research

and justification for recitation model.• ~1.5 days on content - modeling recitation

sessions with 6 of the content units.

Support

• At weekly TA meetings suggestions for use of the materials were presented.

• Areas of potential student confusion were pointed out.

Evaluation

• Observations of Recitation sessions were done, limited.

• Students were interviewed about aspects of the course.

• TA feedback in the form of written comments at various times during semester.

• Results of Concept Survey.

Results to Date

• Seeing some movement in the desired direction.

• TA training was successful!– Faculty comments– TA feedback

Thanks!