1. Zdeslav Hrepic Dean A. Zollman N. Sanjay Rebello
Students’ understanding
and perceptions of the content of a lecture
Zdeslav Hrepic Dean A. Zollman N. Sanjay Rebello
AAPT National Meeting
Madison, Wisconsin, 2003
Kansas State University Physics Education Research Group
Supported by NSF ROLE Grant # REC

2. Motivation Earlier study
16 students interviewed pre- and post- instruction (on sound propagation)
All stated they paid special attention to find the answers on interview questions
Progress far from satisfactory.
A student’s comment during the post interview: “Did we learn all this stuff in class? Like should I know all of these answers?”
A researcher who observed the lecture believed that:
The answers on interview questions were given out “on a silver platter”.

3. Research questions
What kind of questions do students perceive as being answered in a lecture?
How are students’ perceptions of a lecture related to their prior knowledge?
How do students’ perceptions of the content of a lecture compare with those of experts?

4. Methodology Research tool Idealized (video) lecture
Semi-structured interview
Participants
18 students
from KSU concept-based introductory physics class
9 experts
with MS or Ph.D in Physics, or with fulfilled course requirements for Ph.D in Physics + correct 1st question
The Lecturer

5. Research protocol (Slide 1 of 2)
All participants watched the segment of a video lecture related to sound propagation presented by Dr. Hewitt.
Participants were asked…
Before the lecture
to answer a set of questions related to sound propagation - some addressed in the lecture and some not.

6. Research protocol (Slide 2 of 2)
During the lecture
to record when any of the questions were addressed.
to record the answer as given by the instructor.
to indicate the extent to which the question was addressed on a Likert scale (1 – 5).
After the lecture
to determine if any further answer to any of the questions can be inferred from what lecturer said.

7. Survey Questions - Paraphrased
How does sound propagate through the air?
Does the speed of the sound in air depend on temperature?
Does the speed of propagation of sound depend on the motion of the source?
How does the speed of sound generally compare between solids, liquids and gases.
Does sound propagate in a vacuum?
Does sound affect a dust particle floating in front of the loudspeaker? If so, how?

8. Advantages of “idealized” experimental lecture (Slide 1 of 2)
The lecturer…
was nationally and internationally recognized teacher and the textbooks author.
Students…
already had their class lectures on the same topic before the experiment.
already took their exams related to the topic.
By taking the test right before the lecture students...
got familiar with the questions they are supposed to find answers on during the lecture.
mentally “warmed up” for the topic.

9. Advantages of “idealized” experimental lecture (Slide 2 of 2)
In addition:
Students were allowed to pause/stop and rewind the tape any time they wanted during the lecture.
No typical classroom distractions like noise, conversations and interruptions.
The "lecture time" was nearly 1/3 of the normal class time (~ 14 minutes).
Both, the lecturer and students were native English speakers.

10. Results Which questions were addressed and how
Question seen as addressed by
Question
Students N=18
Experts
N=9
Lecturer
1 (Propagation)
83%
100%
Yes
2 (Temperature)
3 (Moving Source)
27.8% 0% No
4 (Medium)
5 (Vacuum)
16.7%
77.8%
6 (Dust particle)
Hint

11. Results – how well questions were addressed
Average Completeness of answers (scale 1-5) as rated by
Question
Students N=18
Experts
N=9
Lecturer
1 (Propagation)
3.8
4.5 4
2 (Temperature)
4.8
4.7 5
3 (Moving Source) 2
4 (Medium)
4.1
5 (Vacuum)
2.3 3
6 (Dust particle)
2.2

12. Results – how frequently questions were addressed
Average No. of Times questions addressed
Question
Students N=18
Experts
N=9
Lecturer
1 (Propagation)
1.2
2.1 -
2 (Temperature)
1.3
2.4
3 (Moving Source) 1
4 (Medium)
1.4 3
5 (Vacuum)
6 (Dust particle)

13. Results Students’ Correctness (N=18)
Question
Students that answered correctly and with relevance
1 (Propagation) 2
2 (Temperature) 17
3 (Moving Source) 1
4 (Medium)
5 (Vacuum)
6 (Dust particle)

14. Results Students’ Correctness (N=18)
Question
Students that answered correctly and with relevance
Of these, answered correctly also before the video
1 (Propagation) 2 1
2 (Temperature) 17 8
3 (Moving Source)
4 (Medium) 12
5 (Vacuum)
6 (Dust particle)

15. Mental model pre-post instruction dynamics
The nature of sound propagation not addressed (4).
Inconclusive model. Inconsistent with wave. (3).
Retained the Incorrect model (7)
Retained the Wave model (1)
Improved model to a less incorrect one (2)
Improved model to Wave (1)

16. Results - Making Inferences
20 inferences made (11 by students and 9 by experts).
14 correct inferences made (4 by students and 10 by experts).
Correct inferences made exclusively by participants who knew the correct answer also before the video lecture.

17. During the lecture, and especially if the question is not explicitly addressed, students may...
hear “what makes sense” and overlook what is actually stated.
concentrate on details and record them incorrectly.
hear/understand exactly the opposite of what the instructor said.
hear what was not said.
perceive the incorrect answer when no answer is given to the question.
…etc.

18. Conclusions (Slide 1 of 2)
In general from our study it appears that…
Students correctly recognize simple answers that are explicitly stated, preferably multiple times.
If answer is not explicitly stated, they try to make sense of things in ways not intended by the instructor.
Experts tend to believe that questions are addressed
more frequently than the students do.
more thoroughly than the students do.

19. Conclusions (Slide 2 of 2)
Students are likely to make the correct inference only if they know the answer before the lecture.
There is a number of misunderstandings that can occur during the lecture even if lecture conditions are far better than in a regular classroom.

20. Acknowledgements and References
This work is supported in part by NSF grant # REC
The authors wish to thank Dr. Paul Hewitt for his kind participation in this research. His input was invaluable for analysis of our data.
References
Cooper, P. J., & Simonds, C. J. (2003). Communication for the clasroom teacher. Boston, MA: Allyn and Bacon.
Hewitt, P. G. (1991). Vibrations and Sound II [Video tape]: Addison-Wesley.
Hewitt, P. G. (1998). Conceptual Physics (8th ed.). Reading, MA: Addison-Wesley.
Hrepic, Z., Zollman, D., & Rebello, S. (2002). Identifying students' models of sound propagation. Paper presented at the 2002 Physics Education Research Conference, Boise ID.
Kvasz, L. (1997). Why don't they understand us? Science and Education, 6,
Zollman, D. (1996). Millikan Lecture 1995: Do They Just Sit There? Reflections on Helping Students Learn Physics. American Journal of Physics, 64,

21. Contact / More Information
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