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IR Clickers and ConcepTests: Engaging Students in the Classroom


Margaret R. Asirvatham
Department of Chemistry & Biochemistry
University of Colorado at Boulder

02/15/05 to 02/18/05


Research in science education (Hake, 1998) has shown that active participation by students, coupled with peer instruction, enhances learning. Eric Mazur (1997) stresses the importance of designing questions that test conceptual understanding (ConcepTests) and "provoke discussion and interaction" in the classroom. Landis et al. (2001) shared the excitement of teaching introductory chemistry classes using ConcepTests and evaluated student responses in a variety of ways including "a raising of hands, a displaying of signs," and using electronic response systems.

The use of infrared (IR) clickers and receivers to collect real-time feedback in the classroom is rapidly gaining momentum and is especially embraced by instructors teaching large lecture classes or those who wish to switch from traditional lectures to interactive-engagement methods. Dubson (2001) introduced IR clicker technology using the H-ITT system into his large physics class at the University of Colorado in Boulder and supports clicker registration for 25 courses in a variety of disciplines, primarily math, science, and engineering. The logistics of implementing the H-ITT system is well documented by Dubson (2001) and most recently by Duncan (2005). Asirvatham and Bierbaum (2003) first introduced IR clickers into three lecture sections of freshman general chemistry in Fall 2003 to encourage student-centered learning in large classes that were taught in the traditional lecture format and to focus on conceptual understanding to enhance retention of knowledge. The experience has been positive for both the students and the instructors, and IR clickers and ConcepTests are now used in several chemistry classes. This paper provides information about the ways in which electronic response systems were used to facilitate constructivist pedagogy in the classroom and to promote the art of engagement described by Middlecamp (2004).


Overview of Clicker Technology Implementation

Clickers in the Classroom: How to Enhance Science Teaching Using Classroom Response Systems (Duncan, 2005) is an excellent resource for anyone who is interested in using a simple electronic response system. The classroom is equipped with IR receivers (one receiver per 25 students, and one power supply for every five receivers) and the data collected is stored on a computer that runs the required software. Students purchase individual clickers (IR transmitters, Figure 1) that have unique ID numbers, and important information is registered on-line by course number (Dubson, 2005).



Figure 1. IR Clicker showing ID inside battery compartment
(Displayed on the H-ITT web site at



A LCD projector (sometimes two of these are required in very large lecture halls) displays the clicker identification numbers of students as responses are received. An example of such a display is shown in Figure 2. Each student's ID is color coded and always appears in the same location. In very large classes, fewer ID digits are displayed for practical reasons and the display is also posted on the course web page.



Figure 2. Display of student identification numbers



The ConcepTest is projected on the screen and students are typically allowed 2-3 minutes to discuss the answer and click in their responses. The instructor controls the allotted time by monitoring the display for the number of responses clicked in at a given time. Data collection is terminated and the histogram of the responses (percentage of responses versus response A, B, C, D, or E) replaces the ID display. The correct response may be represented in a different color. If the instructor chooses to compare individual responses with the results of peer interaction, the histogram display can be suppressed. However, all the data is retrieved later. The data is saved and converted to an Excel file for further analysis.


Clicker technology has improved rapidly and the third generation of H-ITT IR clickers includes two-way IR transmitters that eliminate the need for an LCD projector to display clicker identification numbers. The new generation of clickers must be used with the new receivers that are still compatible with the old clickers.


Conceptual Understanding and Peer Interaction

The success of the Peer-Led Team Learning (PLTL) approach in actively engaging students is documented (Gosser et al., 2001 ). Students are encouraged to discuss the answer with their nearest neighbors and to convince one another of the validity of their reasoning. Lecture demonstrations provide opportunities to engage students in predicting or rationalizing outcomes. Balloons cooled in liquid N2 were allowed to warm up to room temperature and Question 1 was presented as the students observed the demonstration.


Question 1: What is the relationship between the volume (V) and Kelvin temperature (T) of an ideal gas {NOTE: n (# of moles) and P (pressure) are constant}?

A. V is directly proportional to T.

B. V is inversely proportional to T

C. There is no relationship between V and T.


As Figure 3 shows, 96% of the students answered correctly. A strong performance by the class builds confidence and encourages the students to stay involved.

Figure 3: Histogram of responses to the Charles's law demonstration.


A poor performance on a ConcepTest (Question 2) gets the immediate attention of the students and the instructor. The students felt confident that they followed the discussion on gas density but the error was to overlook the diatomic nature of chlorine as admitted by the students.


Question 2: Which one of these gases has the highest density at STP?



Atomic Mass (amu)












      A. Argon       B. Carbon dioxide       C. Chlorine       D. Nitrogen

Only 6% of the answers were correct as shown in Figure 4. A similar question was included on the exam and 86% of the students selected the correct answer.


Figure 4: Histogram of responses to Question 2


The effectiveness of peer interaction is evident from the results displayed in Figure 5. The students were extremely cooperative when requested to first answer individually and became immersed in serious discussion when permitted to collaborate with other students. The percentage of correct answers increased from 68% to 86%, a gain of 18 percentage points and a normalized learning gain of 0.56 (Hake, 1998). The normalized gain is represented as the ratio of the actual gain relative to the maximum gain possible.



Figure 5: The effectiveness of peer interaction.


Student responses to the question in Figure 5 prompted the instructor to review the application of Le Chatelier's principle to predict the direction of the equilibrium shift when pressure-volume changes occur in reactions involving gases. It was also an opportunity to reinforce the concept that the equilibrium constant does not change at constant temperature. Teaching and learning is transformed as student responses drive the lecture and shift instructional strategies.


Identifying Misconceptions and Challenging Topics

Electronic responses to ConcepTests provide real-time assessment that is beneficial to the student and the instructor. Misconceptions can be addressed, reasoning ability can be improved, strategies to eliminate incorrect answers can be discussed, and the instructor can identify topics that are difficult or challenging for the students. The results shown in Figure 5 confirm the misconceptions of about 20% of the students who failed to recognize that the equilibrium constant did not change under constant temperature conditions. This percentage dropped to about 8% after peer interaction, and the discussion that followed addressed the needs of this group of individuals. Data collected over three semesters helped to identify some of the concepts and/or topics that are difficult or challenging for students in first-semester general chemistry. These are listed, although the list is not comprehensive.

-         Writing correct formulas and naming compounds

-         Balancing combustion reactions

-         Solution stoichiometry

-         Direct and inverse proportions (gas laws)

-         Comparing lattice energies

-         Lewis structures and predicting shapes and net dipole moment

-         Constitutional Isomers

-         Predicting relative vapor pressures


Reinforcement to Enhance Knowledge Retention

Our data shows that students struggle with the concept of constitutional isomers when the unit on organic chemistry is presented. This problem was addressed by using constitutional isomers as examples when discussing the prediction of relative physical properties such as boiling points. Questions 3 and 4 illustrate this point. The parentheses contain information about the percentage of responses to each answer and the asterisk refers to the correct answer.


Question 3: Draw all possible constitutional (or structural) isomers of C5H12. The maximum number of constitutional isomers is

A) 2 (21%)     *B) 3 (61%)     C) 4 (15%)     D) 5 (2%)     E) 6 (1%)


Question 4: Which structural isomer of C5H12 will have the highest boiling point?


*A) CH3CH2CH2CH2CH3 (n-pentane) (91%)


B) CH3CH2CH(CH3)2 (2-methylbutane) (2%)


C) (CH3)4C (2, 2-dimethylpropane) (7%)


Survey Questions

Audience response systems may be used to collect useful information about students' attitudes towards the use of IR clickers to enhance learning as well as data about their prior knowledge and preparation in math and science. Some of these results are presented in Figures 8-11.



Figure 8. Students' perception of the impact of ConcepTests on their learning


1) How do you feel about answering ConcepTests using Clickers?


A) I love it

B) I like it

C) I am neutral

D) I dislike it

E) I hate it






2) Have ConcepTests encouraged improved performance in this course?




A) Yes

B) Kind-of

C) Neutral

D) Not really

E) No






3) Have you used the ConcepTests posted on the course web page?




A) I used them throughout the semester

B) I used them quite frequently

C) I used them just before exams

D) I never used them

E) I was not aware that they were posted

on the course web page






4) How has the use of IR Clickers affected your attendance?




A) Strong positive effect on attendance

B) Mildly positive effect on attendance

C) Neutral effect on attendance

D) Mildly negative effect on attendance

E) Strong negative effect on attendance







Figure 9: Student responses to survey questions pertaining to the use of ConcepTests and IR clickers.



Figure 10: High school chemistry preparation 
(The three colors represent data for three lecture
sections of the same course.)


Figure 11: High school math preparation 
(The three colors represent data for three lecture
sections of the same course.)



The data shows that a significant number of students like using IR Clickers to facilitate learning in chemistry. For about 40% of the students, the highest level chemistry course was in the sophomore year of high school and about 5% either took chemistry in their freshman year or never had a chemistry course. Do these students account for the approximately 40% that earn grades of D or F or drop the class? It was surprising to note that more than 80% of these students had taken calculus or pre-calculus in high school and still experienced difficulties with solving problems that required basic math skills.


Class Participation and Reward System

In Fall 2003 and Spring 2004, points earned for participation in ConcepTests using IR clickers were treated as bonus points. A correct answer received 3 points and 1 point was given for in-class participation. The maximum points possible were normalized to 50 bonus points. Class attendance, tracked using clicker responses, improved significantly to about 80% compared to around 50-60% prior to the use of clickers. A preliminary attempt was made to look for some correlation between class participation and course grade; these results are shown in Figures 12-14. For each letter grade, the percentage of students earning 0-10, 11-20, 21-30, 31-40, and 41-50 bonus points is shown. The clicker scores were adjusted to compensate for absences, clicker malfunctions, and other potential problems.



Figure 12: Clicker point distribution in General 
Chemistry I in Fall 2003


Figure 13: Clicker point distribution in General 
Chemistry I in Spring 2004



A majority of the students in General Chemistry I (Figures 12 and 13) who received an A in the course earned 80% or more of the clicker points while the majority of the students who failed earned less than 40% of the clicker points. A significant majority of students who earned 80% or more of the clicker points also passed the course with a grade of A, B, or C. What happened to the small number of students who participated in ConcepTests and earned 80% or more of the clicker points but earned a D or F in the course? Did they not do the drill and practice outside class that is necessary to succeed in the course or did they simply benefit from the peer interaction in class? The results for General Chemistry II in Figure 14 represent the performance of students who successfully completed General Chemistry I in Fall 2003 (Figure 12). The distribution shows that students who received grades of A, B, or C generally earned 60-80% of the clicker points. The sequence course was taught by a different instructor who used fewer ConcepTests per lecture and the second semester course is generally considered to be more challenging and more difficult. In our experience, many students earn a lower letter grade in the sequence course, and this was also observed after we implemented ConcepTests.



Figure 14: Clicker point distribution in General Chemistry II in Spring 2004


In Fall 2004, the points earned for ConcepTests were included in the course grade and accounted for 5% of the final grade. The data has not yet been analyzed.


Small Classes and Upper Division Courses

Small classes lend themselves to innovative teaching and learning methods and some instructors question the need to use electronic response systems in these classes. Bierbaum (2004) used IR clickers and ConcepTests in a physical chemistry course for about 50 engineering students, and the results are shown in Figures 15 and 16. Group A represents those students who earned an A in the course. These students consistently performed well on ConcepTests and the student with the lowest number of clicker points still earned 80% of the available points. In Group BC, the three students who earned a C had clicker points that ranged from 20-35 out of a possible 50 points. One student earned a B in the course and had only 10 bonus points. However, both the instructor and the students provided positive feedback about the implementation of the audience response system.



Figure 15. Clicker results for students who earned Figure 16. Clicker results for students who earned

an A in the course. a B or C in the course.



Electronic response systems can be used to actively engage students in the learning process and change the dynamics of interactions in the classroom, especially in large lecture classes. The real-time assessment of students' understanding of concepts provides valuable feedback to both the students and the instructor, allowing the instructor to address misconceptions and focus on reasoning ability when necessary.

Peer instruction empowers students, encourages them to ask questions of each other, and promotes learning by teaching. Our data for three large lecture sections (180 - 360 students) of the same course is very similar; these results challenge the instructor to focus on the needs of the students and develop questions that "provoke discussion and interaction." Prior knowledge can be assessed as the instructor provides incentives to read the textbook prior to lecture. Lecture demonstrations have become more effective teaching and learning tools as the instructor finds creative ways to present the experiment and engage the students in making predictions or explaining observations and/or results.

Problem solving using basic mathematical skills is addressed in ConcepTests that do not require the use of calculators. Recitations are conducted by teaching assistants using the tutorial format where students work in small groups on assigned problems, and challenging questions are assigned on electronic homework. The chemistry help room is another place where students help each other under the watchful eyes of one or two teaching assistants.

The ConcepTest approach using electronic response systems creates a lot more work for the instructor, and the students are initially disappointed to find that the instructor does not work out tons of problems in class. However, students learn more by doing and we plan to monitor and assess knowledge retention as these students enroll in upper division chemistry courses.



Asirvatham, M. R., & Bierbaum, V.M. (2003). Unpublished results, University of Colorado at Boulder.

Dubson, M. (2001). "Clickers": Electronic Audience Feedback in the Classroom.

Dubson, M. (2005). Clicker registration.

Duncan, D. (2005). Clickers in the Classroom: How to Enhance Science Teaching Using Classroom Response Systems. San Francisco: Pearson Education, Inc.

Gosser, D. K., Cracolice, M. S., Kampmeier, J. A., Roth, V., Strozak, V. S., & Varma-Nelson, P. (Eds.) (2001). Peer-led Team Learning: A Guidebook. Upper Saddle River, NJ: Prentice Hall.

Hake, R. R. (1998). Interactive-engagement versus traditional methods: A six-thousand-student survey of mechanics test data for introductory physics courses. American Journal of Physics66 (1),       64-74.

Landis, C. R., Ellis, A. B., Lisensky, G. C., Lorenz, J. K., Meeker, K., & Wamser, C. C. (2001). Chemistry ConcepTests: A Pathway to Interactive Classrooms. Upper Saddle River, NJ: Prentice       Hall.

Mazur, E. (1997). Peer Instruction: A User's Manual. Upper Saddle River, NJ: Prentice Hall.

Middlecamp, C., (2004). Teaching Non-Majors: The Art of Engagement. How and Why Should We Teach Chemistry for Non-Science Majors, Winter 2004 CONFCHEM.

Copyright © 2005 by Margaret R. Asirvatham, all rights reserved.

Published online: January 18, 2005 for the Winter 2005 CONFCHEM: Trends and New Ideas in Chemical Education