Teaching Assistants Facilitating Conceptual Understanding in an Introductory Chemistry Laboratory Course Using the Science Writing Heuristic: Quantitative and Qualitative Aspects

Sozan Omar1, Brian Hand2 & Thomas Greenbowe3 Curriculum & Instruction1,2 and Department of Chemistry3

Iowa State UniversityAmes, IA 50010

AbstractImplementation of the science writing heuristic (SWH) has proven to facilitate better conceptual understanding from laboratory activities. However, the implementation requires changes to the instruction compared to the pedagogy used with traditional laboratory activities. In this study, the researchers focus on the teacher effect in promoting conceptual understanding when implementing the SWH. Students’ scores on the practical examination and observations of four teaching assistants involved in the SWH laboratory sections were collected. Results showed a positive relationship between the implementation of the teacher’s template and student performance. Students in the laboratory section, where the teaching assistant implemented teaching strategies as defined by the SWH, obtained significant higher laboratory examination scores than students in laboratory sections where the teaching assistants did not properly implement the SWH.

IntroductionIn developing the SWH, Hand and Keys (1999) constructed a template for both, teachers and students. The student template is centered on structuring the learning from the outcomes from the laboratory activities, while the teacher template focuses on the necessary pedagogy to support learning. Using the SWH provides opportunity for the students to think, negotiate ideas with peers and teacher, link claims to evidence, and reflect upon their learning through writing the laboratory report. However, using the SWH requires change to the pedagogy used by teachers for traditional laboratory activities. Teachers need to adopt more student-centered approaches so as to encourage students to take more control over their learning and facilitate their inquiries and negotiations. If the SWH were not viewed as the implication of both templates, then the student template component would merely represent a different writing format for a laboratory report and thus lose its significant meaning.

The Science Writing Heuristic (SWH) Templates

Teacher’s template

• Exploration of pre-instruction understanding

• Pre-laboratory activities

• Laboratory activity

• Negotiation- individual writing

• Negotiation- group discussion

• Negotiation- textbook and other resources

• Negotiation- individual writing

• Exploration of post-instruction understanding

Student’s template• Beginning questions or ideas

What are my questions about this experiment?• Tests and Procedures

What will I do to help answer my questions?• Observations

What did I see when I completed my tests and procedure?

• ClaimsWhat can I claim?

• EvidenceWhat evidence do I have to support my claim? How do I know? Why am I making these claims?

• Reading How do my ideas compare with others?

• ReflectionHow have my ideas changed

Comparison and Contrast for the SWH Format vs. the Standard Format

Laboratory Format

SWH Standard

Beginning questions or ideas

Tests and procedures

Observations

Claims

Evidence

Reflection

Title and purpose

Outline of procedure

Data and observations

Discussion

Balanced equations, calculations, or graphs

No equivalent

Research Questions

• Do students who use the SWH demonstrate better understanding than students using traditional laboratory approach in freshman chemistry laboratory classes?

• Does the pedagogical implementation affect student performance when using the SWH?

Research Methodology

A Six-week Pilot StudyFall, 2001

At one of theMidwestern universities

In an introductory laboratory chemistry

course

122 students involved

out of 603 students

Same professorfor the lecture

course

Same laboratory manual and activities

for all groups

Content

Lecture Laboratory

Preparation of a salt, empirical formula of

some simple compound, acids bases and their reactions,

calorimetry, andapplying Hess’s Law

Stoichiometry calculations including

calculations of aqueous

reactions and thermochemistry

Teaching Assistants

Jeffery* Linda* Bob* Danny*

SWH Standard SWH

StandardSWH

Standard

19 Students 14 Students 19 Students 18 Students

18 Students 17 Students

SWH

17 Students

* All names are pseudonyms

Quantitative Analysis

Prior to the study

Analysis of Variance for the ACS California Diagnostic

Exam Scores with groups (SWH and standard) as

independent variable

After The Study

A 2x4 Analysis of Covariance for the laboratory mid-

exam scores with both groups and TAs as independent

variables and the ACS California Diagnostic Exam as a

covariate

Qualitative analysis

Observations

• Observations of TA’s performance in four laboratory SWH periods

• For each observation, the types of interactions promoted were classified and coded.

CodingOne-way interaction from:

- TA to students in large group: LG (TA Std) in small group: SG (TA Std)

- students to TA in large group: LG (Std TA ) in small group: SG (Std TA)

- student to student in small group: SG (Std Std)

Two-way interaction between: - TA and students in large group: LG (TA Std) in small group: SG (TA Std)

- Student and student in large group: LG (Std Std) in small group: SG (Std Std)

Codes & Examples for All Types of Classified Interactions

SG (Std Std): Discussion of the beginning questions

SG (Std Std): Providing calculation for the results

SG (TA Std): Answering a question with a question

SG (TA Std): Answering student’s questions

SG (Std TA): Checking student’s beginning questions

LG (TA Std): Discussion of claims & evidences

LG (Std TA): Sharing the beginning questions

LG (TA Std): Modeling inquiry beginning questions

LG (Std Std): More control of the activity

Quantitative Results

Prior to The StudyThe result of the ANOVA for

participants’ ACS California

Chemistry Diagnostic Exam

with groups as the

independent variable was not

significant,

F (1,125) = 0.288, p<0.592,

η2 = 0.002

After The StudyThe results of 2x4 ANCOVA analysis:

• was not significant for the groupsF (1,114) = 2.624, p<0.108, η2 = 0.023,

• was significant for the TAs effectF (3,114) = 11.88, p<0.000, η2 = 0.238

TAs Effect

TAsGroups Differences*

Prior to the Study After the Study

Jefferyt (0.0167, 31) = 1.31

p<0.201 t (0.0167, 31) = 3.42

p<0.002

Linda t (0.0167, 33) = - 0.97 p<0.34

t (0.0167, 33) = -1.15 p<0.26

Bob t (0.0167, 35) = 0.25 p<0.80

t (0.0167, 35) = 0.12 p<0.91

* á = 0.017** Statistically Significant

Qualitative Results

TAsTwo-way

interactionTotal Percentage

Total percentage

Jeffery(41 Total)

SG 21 5183

LG 13 32

Linda(21 Total)

SG 6 2948

LG 4 19

Bob(27 Total)

SG 6 2233

LG 3 11

The results of this study indicate that no significant difference exist among groups (SWH and Standard); however, a significant teacher effect exists among the TAs. This suggests that the teaching strategy employed has an effect on student performance. The TA (Jeffery), whose SWH group performed significantly better than his standard group in the laboratory mid-exam, had promoted more two-way interactions (83%) compared to the other two TAs, Linda (48%) and Bob (33%). The qualitative results provide supporting evidence that to facilitate more learning from laboratory activities while using the SWH required changing to the traditional teaching strategy to adopt more student-centered through implementing more two-way interactions, whether in small or large group.

Conclusion Future Work

The researchers would consider the following in future work: • Larger sample size for both TAs and Students• Implement the study for a larger time• Vary the observation periods along the study time• Students’ performance in the lecture course

Reference

Hand, B., and C. Keys (1999). Inquiry investigation: A new approach to laboratory reports. The Science Teacher, 66, 27-29.

Acknowledgement This study was funded by the National Science Foundation (NSF), project number 0088709