Due to the nature of large enrollment courses, it is difficult to create intimate learning environments where students can seek advice from the instructor. One alternative to the large lecture is to offer small discussion courses taught by highly trained graduate teaching assistants. These small courses allow students to interact with skilled instructors while keeping costs low. In this paper, we discuss differences in student exam scores between a large lecture taught by an experienced lecturer and a small discussion taught by an trained graduate student at a large Research 1 institution.

1. Controlling Free
Radicals: Effectiveness
of Graduate TAs in large
enrollment courses
Charity Flener-Lovitt and Paul Kelter

2. In modern colleges,
education is a commodity
$mall Classes > Large Classe$
Profe$$or$ > Graduate $tudents

3. General Chemistry at Illinois
All students
Weak chemistry Chemistry
Other students
background Majors
(1900)
(600) (250)
Chemistry 101 Chemistry 102
Chemistry 202
Large professor
Small TA taught
taught lecture
discussion
(1000)
(900)

5. Graduate student or freshman?
Assume that a beaker of water on a hot plate has been
boiling for an hour. Within the liquid, bubbles can be seen
rising to the surface. What are the bubbles made of?
Water breaks down into H2 and O2
2H2O --> 2H2 + O2 freshman
These are air bubbles. With increasing temperature, the
solubility of air in water decreases and since at room
temperature there is always some air dissolved in water,
it gets pushed out of solution
Graduate student
George Bodner, J Chem Ed. 68, 1991, 385.
University of Illinois freshman chemistry exam.

6. Comparison of exam grades of Lecturer
and TA taught courses
100
90 76.26 79.09 77.95 78.65
80
70 77.68
Grade
75.32 75.51 76.94
60
50
40
Large Lecture
30
20 Small Discussion
10
0
1 2 Exam 3 Final

7. Final Grade Distribution between TA
sections
0.3
TA - Mr. Cobalt
0.19
0.2
Average
2.61
Deviation from Average GPA
0.1
0.04 0.04
0
0
-0.11 -0.03
-0.1 -0.14
-0.11 -0.19
-0.14
-0.2 -0.17 -0.16
-0.18
-0.2
-0.3 -0.27 -0.26
-0.29
-0.4 -0.37
-0.43
-0.5

8. Compare test scores of Mr. Cobalt
and Dr. Potassiam
Exam 1 Exam 2 Exam 3
Cobalt 73.5 82.3 80.4
Potassium 72.3 79.1 78.0

9. Improvement of unprepared
students
‘Weak students become intermediate’

10. What made Cobalt effective?
4th-year graduate student
8 semesters teaching experience
active involvement in TA mentoring
spent 1-2 hours preparing lecture each week
neglected duties in research laboratory

11. TAs with mentorship
responsibilities
0.3
Average
0.19
0.2
GPA= 2.68
Deviation from Average GPA
0.1
0.04 0.04
0
0
-0.11 -0.03
-0.1 -0.14
-0.11 -0.19
-0.14
-0.2 -0.17 -0.16
-0.18
-0.2
-0.3 -0.27 -0.26
-0.29
-0.4 -0.37
-0.43
-0.5

12. Filtering system for second course

13. Student’s perform better in later course
TA Taught Discussion
40% small discussion students
15 - 20 TAs
Professor Lecture
Graduate student sections performed worse

14. The other student....
graduate students are teachers in training
small discussions give students the
opportunity to teach without losing
This course is enormously popular with
graduate students who want to teach!

15. How to utilize TAs
effectively
Hire early
Allow TAs to have effective time to prepare
lectures (limit lab responsibilities)
Group TAs into mentorship groups
Provide regular feedback on teaching
practices

16. Acknowledgments
Advisors
Paul Kelter Support
Greg Girolami UIUC General Chemistry Staff
Grad I-team
EOL 585 Students
Chemical Education Students UIUC Division of Management Information
An Phong Le
Kevin Tucker Funding
Jordan Beck University of Illinois at Urbana-Champaign
Phil Janowicz
Richard Helmich
Tim Richmond