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Teaching with Technology
James P. Birk Arizona State University Tempe, AZ 85287
Automated, Web-Based, Second-Chance Homework Randall W. Hall, Leslie G. Butler, Saundra Y. McGuire,* Sean P. McGlynn, Gary L. Lyon, Ron L. Reese, and Patrick A. Limbach Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803; *
[email protected] Pedagogical techniques that foster active learning are critical to the development of meaningful learning in college chemistry. Several articles have focused on techniques such as collaborative learning (1, 2), writing exercises (3), poster presentations (4, 5), and inquiry-based laboratory experiments (6 ). The incorporation of active learning strategies into large lecture sections is particularly difficult because of the impersonal atmosphere associated with the size of the room (7). Another challenge posed by large class-sections is the development of effective assessment tools, ones that provide accurate feedback to both students and instructors (8, 9). Scantron examinations are often the instrument of choice because of the lack of time and personnel. Rationale We chose to use Web-based second-chance homework to address the need both to increase active learning in our students and to give them rapid and accurate feedback. In large classes, homework is often the primary method for engaging students in learning chemistry. Homework can also be an excellent tool for fostering critical thinking skills. However, relatively few students are sufficiently motivated to expend considerable effort on homework problems if there is no perceived reward (such as a grade). Additionally, in order for homework to be an effective teaching tool, feedback and correction should be provided in a timely manner. For the feedback to be useful in improving understanding, it must be taken seriously by the students. Web-based delivery of homework combined with a unique database design can accommodate a “second-chance homework” option. When a student incorrectly answers an item on the original assignment, he or she receives detailed feedback on the error and is given a second problem of similar character within 48 hours. The students are motivated to utilize the feedback because it will help improve their grade on the homework and, ultimately, their grade in the course. The instructor workload has three parts. First, a double set of questions must be generated pair-wise, one question being used on the original assignment and the second reserved for the second-chance homework. Second, a detailed feedback must be written by the instructor and given to the student detailing the error leading to each erroneous answer in the original homework question set. Third, a reliable yet flexible database must be generated to monitor the progress of each student through the homework assignment. The focus of this work is on the development of the homework sets and the structure and organization of the programming and procedures developed for the database. All programming is done in C and HTML. 1704
Developing the Homework Sets Four instructors, each of whom taught a large section of the first semester of a two-semester course in General Chemistry, collaborated on the development of the Webbased second-chance homework sets. One instructor selected the problems or questions for each assigned chapter. These were used as the models for construction of the multiplechoice items for the homework sets. Each instructor developed 2 versions of approximately 25 items, which included both quantitative and descriptive problems and spanned a range of difficulty. The items were a combination of conceptual questions and single-step or multistep problems. Problem sets were designed to include problems having a wide range of difficulty. Therefore, the least experienced, most algorithmic learners could achieve some success, yet the more advanced conceptual learners would still be challenged. All items were written in a multiple-choice format. The homework sets generally contained between 9 and 11 items per assignment. Success on each assignment was roughly defined as “approximately 90% correct answers”. This was set as the success value because students with an average of 90% and above received a grade of A in the course. An example of an item involving algorithmic, one-step problem solving is shown below. Convert a pressure of 300 torr to (i) atm (ii) mmHg A 0.395 atm 300 mmHg B 0.395 atm 300 mmHg C 0.395 atm 300 mmHg D 0.395 atm 395 mmHg E 0.395 atm 395 mmHg
(iii) Pa 3.90 × 10᎑6 Pa 4.00 × 104 Pa 4.00 × 104 Pa 4.00 × 104 Pa 4.00 × 104 Pa
(iv) bar 0.400 bar 0.400 bar 4.00 × 109 bar 4.00 × 109 bar 0.400 bar
The corresponding feedback is: A. Wrong. You divided by (1.01235 × 10 Pa/1 atm) instead of multiplying by it. B. Correct. This is a simple conversion factor problem (see p 356). The appropriate conversions are: (i) 300 torr × (1 atm/760 torr) = 0.395 atm; (ii) 300 torr × (1 mmHg/1 torr ) = 300 mmHg; (iii) 0.395 atm × (1.01325 × 105 Pa / 1 atm) = 4.00 × 104 Pa; (iv) 4.0023 × 104 Pa × (1 bar/1 × 105 Pa) = 0.400 bar C. Wrong. You multiplied by 1 × 105 rather than dividing by it when you converted Pa to bar. D. Wrong. You multiplied by 1 × 105 rather than dividing by it when you converted Pa to bar, and 1 atm does not equal 1000 mmHg. E. Wrong. 1 atm does not equal 1000 mmHg.
Journal of Chemical Education • Vol. 78 No. 12 December 2001 • JChemEd.chem.wisc.edu
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An example of a more challenging, multistep problem is shown below. In a cathode ray tube (CRT), elemental barium metal is added at the last stage of manufacture. In the last step, the CRT is evacuated to remove almost the entire atmosphere, and then the tube is sealed. Even with the best vacuum pumps, trace amounts of oxygen remain in the CRT. The oxygen will react with barium to make barium oxide. Given the following data, calculate how many grams of barium are needed. (a) The CRT volume is 5.1 L. (b) The CRT temperature is 35 °C. Before reaction with barium, the oxygen gas pressure in the CRT is 1.5 × 10᎑6 torr. A. 1.1 × 10᎑7 g B. 0.063 g C. 1.9 × 10᎑8 g D. 0.000083 g E. 9.6 × 10᎑7 g
Programs and Procedures For each assignment, the Web-based homework required four files. Three extra files were created for each class section. The required files were an HTML version (which did not include buttons) and a text file that contained the answer key for both the original and the second-chance homework. The answer key contained the feedback for each question and could contain HTML code, if needed. It also contained the time and date information used to determine when particular
assignments were due. Both the HTML versions of the homework and the answer keys were created in a word processor and then “Saved As Html” to convert to HTML. They were further processed to add the special fields needed for grading. Two created files were the results of the original and second version assignments; they were created in tab-delimited format for ease of import into spreadsheets and databases. The third created file (the “error” file) contained information on each student’s incorrect answers and was used to generate the second-chance homework for that student. The results files included name, student ID number, the response to each question (A, B, C, D, or E, or X if no response was made), and the number of questions answered correctly. The error file contained the student’s name and ID number, the number of each incorrectly answered question, the student’s answer for that question, and the number of the correct response (A = 1, B = 2, etc.). The Web-based homework was administered using the following guidelines (summarized in Table 1). Each homework set had three dates, which were stored in the answer key files: the first time and date that the original assignment could be submitted, the last time and date that it could be submitted (which was also the first time and date that the second version could be submitted), and the final time and date that the second version could be submitted. A C program processed the original and second-version HTML files, inserting buttons and creating additional HTML files needed to implement the homework. For each original HTML file, three HTML files were created: one (without buttons) that was used when a
Table 1. Guidelines for Web-Based Homework Date
Event
Files to Be Created/Modified (Format)
Monday, week 1
Preparation of initial files
1. Original assignment (word processor, no radio buttons) 2. Original assignment answer key (word processor, with due date information, correct answers, and feedback) 3. 2nd-chance assignment (word processor, no radio buttons) 4. 2nd-chance assignment answer key (word processor, with due date information and correct answers)
Programs Used —
Wednesday, Hardcopy of original week 1 assignment distributed to class Preparation of HTML versions of both assignments, using C script
5. For display on Web prior to Monday, 8 a.m., Week 2 (HTML) C script 1 prepares the files. CGI script 1 checks date and displays File 5 6. For use from Monday, 8 a.m., Week 2, to Wednesday, 1 p.m., Week 2 (HTML, with radio buttons) 7. For use from Wednesday, 1 p.m. Week 2 to riday, 1 p.m. Week 2 (HTML, with special codes to allow display of feedback) 8. For use from Wednesday, 1 p.m, Week 2 to Friday, 1 p.m, Week 2 (HTML, with radio buttons) 9. For use from Monday, 8 a.m., Week 2 to Wednesday, 1 p.m, Week 2 (HTML) 10. For use from Wednesday, 1 p.m, Week 2 to Friday, 1 p.m, Week 2 (HTML)
Monday, Student submission of 8 a.m., original homework week 2 to Wednesday, 1 p.m., week 2
11. Results file for original homework, containing each student's response to each question and overall score (tab-delimited) 12. Error file for the original homework, containing each student's answers and the correct answer for each question answered incorrectly (tab-delimited)
CGI scripts 1–3 Script 1 checks date and displays File 6. Script 2 accepts student entry and displays a summary of the responses to the student for proofreading. Script 3 uses File 9 to grade student responses, records response in Files 11 and 12, and displays total score to student.
Wednesday, 1 p.m., week 2 to Friday, 1 p.m., week 2
13. Results file for 2nd-chance homework, containing each student's response to each question and overall score (tabdelimited)
CGI scripts 1 and 4–6 Script 1 checks date and displays File 7 Script 4 displays File 8 Script 5 accepts student entry and displays a summary of responses to the student for proofreading Script 6 uses File 10 to grade student responses and records responses in File 13
Students obtain feedback and gain access to 2nd-chance homework
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Results Figure 1 and Table 2 present a summary of the class results for a homework assignment on gas law problems. In this 11question assignment, 48 of 191 students correctly answered all 11 questions in the original version, and thus did not have access to the second-chance option. Consider, however, the 8 students who answered only 6 questions correctly. Within two days following the initial submission, 7 of them retook 5 questions and answered, on average, about 4 questions correctly. If success on this homework assignment is considered to be 10 correct answers, then the first version yielded 90 students who met this goal and the second-chance option contributed an additional 52 students to the total. The objective of secondchance homework is to encourage students to work harder on the material. As seen, the percentage of students who used the second-chance homework (101 of 143 who had the secondchance option available) was 71%. Typically 70% or more of the students utilized the second-chance option. Students with either very high or very low initial scores tended to utilize the second-chance option less often than students with intermediate initial scores. During the course of the semester, more 1706
11
Correct Answers (No.)
student looked up the homework before the initial due date; the “active” homework file, which contained active answer buttons and was used by students to submit their homework on the Web before the second due date; and the “error” homework file, which was used to display feedback to the student after the second date. Students went to a specific URL, entered their ID and codename, selected the appropriate assignment and section number, and clicked SUBMIT. The resulting scenario depended on the time and date the SUBMIT button was clicked. Before the first allowed submission time/date a copy of the homework assignment was displayed. This was useful if a student lost the assignment distributed in class or was absent when it was distributed. Between the first and final allowed submission time/dates the assignment was displayed and each multiple-choice response had a clickable button. After answers were selected and the CONTINUE button was clicked, the answers were displayed to allow students to make sure they had selected the desired buttons. To change an answer, the BACK button was used. When the student was satisfied with the answers, the SUBMIT button was clicked. The assignment was then graded and recorded in the results and error file, and the student score was displayed. Between the final allowed submission time/date for the original assignment and the final allowed time/date for the second version, the text of each question answered incorrectly was displayed. Below the question was the correct answer, the student’s answer, and the feedback corresponding to that incorrect answer. After reviewing the answers, the student clicked the CONTINUE button. This brought up a different question that was related to the one answered incorrectly on the original assignment. The student could answer the new questions at this time or could print the page, choose appropriate responses off-line, and return before the final submission time/date to submit answers. The submission procedure after this point was the same as for the original assignment, the only difference being that for security purposes, scores were not displayed.
10
2nd chance
9
1st chance
8 7 6 5 4 3 2 1 0
1
2
3
4
5
6
7
8
9
10
11
Correct Answers at First Attempt (No.) Figure 1. For the gas law homework assignment with 11 questions, 191 students submitted 1st-chance homework, achieving scores ranging from 1 to 11 correct (perfect score). Then, some of the students with less-than-perfect scores participated in the 2nd-chance option. For those students, the number of additional questions correctly answered ranged from an average of 4.2 (2 answers initially correct) to 1 (10 answers initially correct). Ideally, the sum of 1st- and 2nd-chance scores would be 10 to 11, indicating mastery of the subject by all students. Here, we see that students with 1st-chance scores of 7 or greater achieved mastery after the 2nd chance.
Table 2. Participation in the Second-Chance Option 1st-Chance
2nd-Chance
No. of Correct No. of Answers Students
No. of Students
% of Students
Most Points Gained
1
5
2
40
4
2
6
4
67
6
3
9
8
89
6
4
6
4
67
6
5
8
7
88
4
6
8
7
88
5
7
20
15
75
4
8
21
19
90
3
9
18
11
61
2
10
42
24
57
1
11
48
0
0
0
than 90% of all students used the second-chance homework option at least once. Figure 2 and in Table 3 show a summary of the class results for a homework assignment on ionic and covalent bonding. The data from the gas law and bonding units are presented as typical examples of results. The results are consistent throughout the homework assignments. These two examples were chosen because one represents an assignment that is primarily quantitative (gas laws), and the other represents an assignment that is primarily conceptual (bonding). Figure 3 shows the relationship between the final semester grade and participation in the 2nd-chance option. As can be seen in the figure, the students who earned higher semester grades participated in the second-chance option to a greater extent than those who earned lower grades. Of the 66 students who earned an A, only 56 would have earned an A without the second-chance option. Of the 56 students who earned a
Journal of Chemical Education • Vol. 78 No. 12 December 2001 • JChemEd.chem.wisc.edu
Correct Answers (No.)
Information • Textbooks • Media • Resources
13 12 11 10 9 8 7 6 5 4 3 2 1 0
2nd chance 1st chance
1
2
3
4
5
6
7
8
9
10
11
12
13
Correct Answers at First Attempt (No.) Figure 2. Results for a homework assignment on ionic and covalent bonding with 13 questions and 204 students submitting 1st-chance homework, achieving scores ranging from 1 to 12 correct (one less than a perfect score). Then, 130 students participated in the 2ndchance option. For students using 2nd chance, the average score is 10.7 correct answers, whereas for students not using 2nd-chance, the average is 7.6 answers correct.
Table 3. Participation in the Second-Chance Option for the Ionic and Covalent Bonding Homework 1st-Chance
2nd-Chance
No. of Correct No. of Answers Students
No. of Students
% of Students
Most Points Gained
1
4
3
75
10
2
3
2
67
4
3
7
6
86
5
4
6
4
67
5
5
12
7
58
8
6
21
14
67
5
7
10
8
80
4
8
36
29
81
5
9
28
21
75
4
10
39
30
77
3
11
33
21
64
2
12
5
3
60
1
13
0
—
—
—
Final Grade
No. of Students
% Parti1st & 2nd cipation
1st Only
A
56
+10
66
80
B
54
+12
56
70
C
50
+3
41
54
D
27
0
24
44
F
26
26
40
Figure 3. The final semester grades are moderately dependent upon the scores of the 2nd-chance homework. For example, 10 students earned A for the semester on the basis of the additional points from the 2nd-chance homework. Overall, the higher the grade the higher was the participation in the 2nd-chance option.
B, only 44 (54 – 10) would have done so without the secondchance option. Of the 41 students who earned a C, only 38 (50 – 12) would have done so without the second-chance option. No students moved from an F to a D as a result of the second-chance option. It is clear that utilization of the second-chance option correlates with the course grade, A and B students making significantly more use of the option than C and D students. (Homework assignments account for approximately 15% of the final course grade.) Of the 56 students who achieved a B grade for the course, 12 required the points earned on the second-chance option to raise their grade from a C. Discussion Web-based second-chance homework is an effective pedagogical tool for active engagement of students in problem solving. Students were invited to submit comments about the second-chance assignments on a form that was accessible from the course home page. Students indicated that the secondchance option enticed them to spend more time with the material and increased their conceptual understanding. The increased time on-task, dispelling of misconceptions, and emphasis on correcting mistakes proved to be very helpful. Some student comments (unedited) are offered below. The second-chance homework is a good source for students to help their grades, but more importantly teach them to teach themselves. Through my personal experiences with second-chance homework I have learned more than the material, but the concept in the material. I strongly believe that having a second-chance for the homework is very good. I’m not just saying this because it helps the student get his/her grade up, but because it gives the student another chance to try the problem, look over the book and the notes again. It helps the student learn the material rather than just spitting out an answer. I think this system is a very clever one. It should be applied in all science and math departments. The second-chance homework helped me out considerably in improving my understanding of the material. Therefore, it boosted my test grades because it forced me to do the problems until I grasped the concepts. Also, by making the homework due on Wednesday and the 2nd chance homework due on Friday, I was constantly forced to work on chemistry instead of waiting until the night before the test to cram. The second-chance homework can be a lifesaver. It helps to pull up grades that may be borderline. Also because the homework problems are quite challenging not many people I talk to make a very good score the first time around (maybe I talk to dumb people, I don’t know). I do know however that with the second-chance homework the grades are usually quite good. I myself improved by 5 or 6 questions. I applaud the second-chance homework and hope that it stays.
Although the reaction to the second-chance homework was overwhelmingly positive, one student wished there were more explicit instructions on how to do the problems, as
JChemEd.chem.wisc.edu • Vol. 78 No. 12 December 2001 • Journal of Chemical Education
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opposed to simply an explanation of the mistake because sometimes the selected answer was simply a random guess. This student wrote: i think it’s great. i just wish it would be more explicit in how to do the problem, because sometimes it suggests something that i did wrong but in actuality i just guessed because i did not know how to do the problem.
The vast majority of students appreciated having the opportunity to correct simple mistakes and to earn back points lost because of them. The following comment is typical: I think 2nd chance homework is a great idea. Sometimes you make careless errors on the first submission and your grade suffers drastically. However, with the 2nd chance you can find out you were careless and fix it and get the credit.
Some of the reasons for the effectiveness of Web-based second-chance homework are discussed below. It addresses student misconceptions of chemical concepts. Many students miss homework items on their first attempt because of misconceptions about the fundamental concepts. The explanations that are provided for the missed homework items point out these misconceptions and provide the correct information. It appears to foster collaborative learning activities among students. Although students were often encouraged to work together before the introduction of Web-based second-chance homework, the degree of cooperation and collaboration seems to have increased since the inception of this type of homework assignment. It encourages students to spend more time and effort on the homework assignments. Because students know that they can boost their course grade by correcting missed homework problems, they spend more time attempting to understand what they did wrong on the original submission of the work and reworking the problems they missed. It permits a greater quantity and variety of homework questions because the instructors are not limited to hand grading of homework problems. More complex problems requiring numerous steps can be assigned because the instructor does not have to pore over the solution sets and analyze individual student work. Instructors have become much more creative in the problems they assign.
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Students can submit the homework at any time from any computer. Commuting students found the homework assignments convenient when they were absent from campus. All students enjoyed the luxury of submission at any time of the day or night. The rapid feedback and the chance to correct errors generate enthusiasm. A concrete incentive for redoing homework items is generated by the direct impact on course grades. This is seldom, if ever, the case with traditional homework assignments in large lecture classes. The level of enthusiasm, as observed by the tutors in the chemistry department tutorial center, is maintained throughout the semester. The Web-based homework assignments are frequently a topic of spirited discussion among groups of students. Second-chance homework is an ideal demonstration of the utility of Web-based teaching tools. Although secondchance homework is possible via more traditional paper-based methods, it is far too labor-intensive for large classes. The efficiency introduced by Web-based delivery makes this powerful teaching tool accessible to instructors of any size class. Acknowledgments A desktop computer for the purpose of generating instructional tools was purchased with funds from a Howard Hughes Medical Institute grant. The LSU Student Technology Fee Program provided funding for several computer laboratories essential for guaranteeing student access to the Internet. Literature Cited 1. Glasser, R. E.; Poole, M. J. J. Chem. Educ. 1999, 76, 699– 703. 2. Towns, M. H. J. Chem. Educ. 1998, 75, 67. 3. Kovac, J. J. Chem. Educ. 1999, 76, 1399–1403. 4. Sisak, M. E. J. Chem. Educ. 1997, 74, 1065–1067. 5. Dunstan, M.; Bassinger, P. J. Chem. Educ. 1997, 74, 1067–1069. 6. Senkbeil, E. G. J. Chem. Educ. 1999, 76, 80–81. 7. Cordes, A. W.; Oliver, M. E.; Butler, L. G. J. Chem. Educ. 1995, 72, 610–611. 8. Hall, R. W.; Butler, L. G.; Kestner, N. R.; Limbach, P. A. Campus-Wide Information Systems 1999, 16, 24–26. 9. Kestner, N. R.; Limbach, P. A.; Hall, R. W.; Butler, L. G. CampusWide Information Systems 1999, 16, 175–178.
Journal of Chemical Education • Vol. 78 No. 12 December 2001 • JChemEd.chem.wisc.edu
