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Physics Department

Texas A&M University

C.H.A.G.S.Computerized Homework Assignment

Grading System

PHYSICS 218 'Mechanics' WEB-BASED HOMEWORK

A.Mershin, D.Toback, J.Walker May 2002

Summary

The Computerized Homework Assignment Grading System (CHAGS) is a web-based interface that collects and automatically grades homework assignments. Currently the system is implemented for Physics 218, which uses Giancoli's University Physics book. This system has been developed based on the AMES math quiz software already adopted by Physics 218. The system does not require installation of any special software and gives students immediate feedback on their performance. It removes the need for graders as well as the problems associated with an imperfect grading process. To use the system, all a professor has to do is pass out a handout to class (see page 12), and download their students' homework grades from the physics web site as necessary.

To see an example of CHAGS (homework assignment of chapter 2), log in with

your Physics Web userid/pass to: http://www.physics.tamu.edu/QUIZ/view.html/CHAG_CH2

In this example, the correct answer is highlighted. When students use the system, they have to pick the right answer from the five (shuffled) possibilities.

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http://www.physics.tamu.edu/QUIZ/view.html/CHAG_CH2

1. Motivation The motivation behind developing an entirely automated system which collects

and grades Physics 218 homework comes from our observation that students who diligently do their homework perform better on the exams and the rest of the course. However, collecting and grading homework in the traditional way presents heavy time requirements for graders, TAs and professors. By requiring that students submit their homework weekly (for credit) we hope to increase the overall class standard and also prevent students falling behind and cramming for exams. We note that this is an improvement over the current system in which the HW is purely optional.

2. Two goals and how they are achieved I. Eliminate the need for homework graders

CHAGS uses software previously developed for the AMES math quizzes (http://www.physics.tamu.edu/QUIZ/). The homework assignments from chapters 1-14 of Giancoli have been coded into the system and the collection and grading is done entirely automatically. There is no need for homework graders and the only action necessary by the professor is to download the final homework grades at the end of the semester (available in text, HTML or Excel format). II. Teach both symbols and numbers

A widespread disability of Physics 218 students is "symbol fear." Students like to use numbers and calculators wherever possible, and frequently lose track of the physics involved in their calculations. To combat this, it is necessary to insist that final answers to appropriate problems be given in formula form before any numbers are substituted. However, one must also teach what numbers are 'reasonable' for various physical quantities such as mass of a person, or acceleration of a car. CHAGS is formulated in a way that requires the students to address both issues and our design is such that students are encouraged to use their calculators only once they have the correct formula.

The system works on the assumption that students have completed their homework in the traditional way (on paper) and have their final solutions and their textbook with them when they log in to the system. They are then presented with a set of problems virtually identical to the ones in their assignment, but with one number or parameter changed and five multiple choice answers. This means that all they have to do is substitute the new number into the formula for their final result and choose the correct answer. This (eventually) demonstrates to the students that re-calculating everything numerically is a time consuming and undesirable way of handling physics problems. This also prevents students from simply copying the answers from the various solution manuals available. Since the final answers are in fact numerical, students still get a taste of what values are reasonable for various quantities.

Our experience tells us that in the beginning, students will try to do the problems during the 40 minutes allotted to them and fail. They will then complain that they do not have enough time. We also know that students who have their answer in symbol notation

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http://www.physics.tamu.edu/QUIZ/

before plugging in the final values have more than enough time to complete the assignments.

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3. The homework assignments:

The homework interface is user-friendly, with a pleasant layout with color images. The questions are multiple-choice with push-buttons and they follow the arrangement of common computerized tests such as the SAT and the GRE.

All questions are based on the homework assignments from Giancoli's book. Subsets of the most appropriate (usually the hardest) questions of each chapter's assignment have been chosen. Each web-homework is between 10 and 20 questions long and each question has five possible replies. There is a time limit of 40 minutes and once a student submits his answers, the system immediately grades them and gives feedback marking correct and incorrect answers. If an answer is incorrect, the right one is not shown, so the student must re-attempt the particular problem. If a question is left blank, there is no feedback. The students are allowed three chances to submit each homework assignment, which gives them an opportunity to re-think any problems that they may have answered incorrectly.

The system asks the student what the solution would be if one number or parameter were modified. This way the students cannot simply copy the numbers from the solution manuals. This also means that they are forced to have their final solutions in symbol form so they can easily substitute the changed parameter.

The example shown below is based on Giancoli's Vol.1, (3rd Edition), Problem 29 Chapter 2 page 40.

(Example) Giancoli Chapter 2 Problem 29The original problem reads: 29. A car accelerates from 12m/s to 21 m/s in 6.0s. What was its acceleration? How far did it travel in this time? Assume constant acceleration. The correct answer is: a=1.5m/s2 and x=99m The web problem reads: Giancoli Ch.2 Prob. 29 (0229) If you change the time to 3.0s then the answer becomes:

a a = 3.0 m/s2, distance traveled = 49.5m b a = 1.5 m/ s2, distance traveled = 99m c a = 4.50 m/s2, distance traveled = 297m d a = 0.75m/s2, distance traveled = 49.5m e It is absolutely impossible to solve this question with the new value of the time!

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4. Submitting the homework

Students taking Physics 218 register with the system following the directions presented in the "CHAGS Handout" (cf. page 12). This begins on the web where students encounter the login screen with directions for setting up a password (http://www.physics.tamu.edu/QUIZ/login.html).

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http://www.physics.tamu.edu/QUIZ/login.html

As soon as the students register with their name, section number, email, phone number and student ID, they are ready to begin submitting homework. All information is communicated via a secure connection. Note that the system gives options for username/password recovery in case the students forget theirs.

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Below is a sample homework-opening screen.

Once students reach the end of the assignment they can submit it for grading or ask for all their answers to be reset. Note that they can change their answers at any time before they hit the "Submit" button.

After students are satisfied with their answers and they hit the "Submit" button, they are shown their score and are given feedback on their performance on the individual questions. If students are unhappy with their score they can simply click on the "Try Again" button and submit again, presumably after they have reviewed the incorrect answers. There is a limit of 3 submissions per homework and only the best score is counted.

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Note that correct and wrong answers are clearly marked and questions left

unanswered are not marked at all.

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4. Professor instructions and student handout

HOW TO USE C.H.A.G.S. IN YOUR CLASS

• Pass out the "CHAGS directions" handout (see next page)

to your students along with your syllabus on the first day ofclass. You may wish to familiarize yourself with its contentsas the students are instructed to start submitting theirhomework in the second week of class.

• Check your students' performance and download theirgrades on the web using the following URL:

http://www.physics.tamu.edu/QUIZ/topten.html

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http://www.physics.tamu.edu/QUIZ/topten.html

CHAGS directions for Physics 218 students

Homework assignments are an integral part of Physics 218 course and they must be submittedvia computer weekly. Experience has shown that students that do all of their homework in a timelymanner, in addition to earning the homework points, do well in other aspects of Physics 218 such asexams and recitation quizzes.

The Computerized Homework Assignment Grading System (CHAGS) is based on themathematics evaluation quizzes (AMES) and is designed to reward you for doing your homeworkdiligently and to give you immediate feedback on how well you're doing.

This system works on the assumption that you have completed all of your homeworkproblems before you attempt to submit your answers. You should bring your textbook, a calculatorand your solutions with the final answer highlighted and in formula form (if possible) to thecomputer that you will use to access CHAGS. Once you log in, you will need to select the week'shomework assignment. The problems are virtually the same as those in the book but one of thenumbers or parameters has been changed (this is done to prevent you from succumbing to thetemptation of copying the solution from the back of the book and also to show the value of obtainingfinal solutions in formula form so substitutions are easy to do). For instance, if the book Ch.1, Prob.1 asks "What is the time taken if the distance traveled is 35milesand the speed is 70mph?" your solution should read:

t = x / v => t = 35miles/70mph = 0.5hours You then should CHECK your answer with the back of the book (for odd numbered questions) or theweb solutions for even numbered questions: (http://physics218.physics.tamu.edu/answer/giancoli/). Once you're done with the entire assignment, you can log into CHAGS (see below) and you will seesomething like: Ch.1 Prob.1 "Suppose the speed is 60mph, what is the new time?" Since you already have the correct formula above, all you need to do is substitute 60mph for v andpick the correct solution from the five available answers.

To register with the system (not necessary if you already have an AMES userid/pass):

• Go to URL http://www.physics.tamu.edu/QUIZ/login.html and follow the on-screeninstructions to set up your AMES/CHAGS account. You should have your Physics 218section number and student ID number handy (NB: only the last five digits of your ID orSSN will be recorded).

Submitting the homework:

• Once you are registered with the system, you can begin submitting homework from anycampus computer with Internet access. Just go to:

http://www.physics.tamu.edu/QUIZ/select.html and choose the correct chapter. Each time you submit, CHAGS will immediately showyou which questions you answered correctly and which not. There is a 40-minute timelimit for each submission (which is ample -but only if you have your answers in formulaform) and you are allowed 3 submissions per homework with only the highest-scoringone counting. For off-campus computers you must either have a TAMUnet modemconnection or have a VPN (Virtual Private Network) client running (e.g. if you have acable modem or DSL connection). For more information about VPN and TAMUnet,please refer to the CIS support staff: (979) 845-8300.

• You can check your homework scores by referring to the bottom of the feedback screen. If you have any questions regarding CHAGS you can email Prof. David Toback

(toback@physics.tamu.edu). For specific problems regarding registration/lost passwords etc. pleaseemail Joel Walker (jwalker@physics.tamu.edu). For questions/comments regarding individual quizproblems contact Andreas Mershin (mershin@physics.tamu.edu).

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http://physics218.physics.tamu.edu/answer/giancoli/http://www.physics.tamu.edu/QUIZ/login.htmlhttp://www.physics.tamu.edu/QUIZ/select.html

5. Student Feedback Prof. Toback's, spring '02 Physics 218 class used CHAGS for all their homework

assignments. We surveyed the students asking them about their experience with this system. The questionnaire and the results obtained are summarized below (grading 4=best, 0=worst). 61 students returned completed questionnaires.

COMPUTERIZED HOMEWORK ASSIGNEMENT GRADING SYSTEM (CHAGS) In an attempt to improve your performance in PHYS218 by motivating you to do homework questions, we have

implemented a web-based homework assignment grading system. This semester was our first attempt and we will use your answers toimprove this system for future generations of Aggies. This questionnaire will be used purely for CHAGS evaluation purposes soplease answer anonymously and honesty. Your comments (on the other side of this sheet) are greatly appreciated and the morespecific the comment the easier it will be for us to fix the problem. 1) Approximately how many of the 12 homework assignments did you submit on the web?

Most or all about 9 about 6 about 3 none () () () () () 4pts 3pts 2pts 1pts 0pts 2) On average, how many times did you submit each assignment?

1 2 3 0 () () () () 3) What was your average score (approximately)?

90-100% 80-89 70-79 60-69 below 60 () () () () () 4) The computer interface was easy to use (including registration/passwords, pushbuttons, feedback screen) Strongly agree Agree Neutral Disagree Strongly disagree () () () () () 5) The wording of the questions was clear i.e. it was easily understood what was asked Strongly agree Agree Neutral Disagree Strongly disagree () () () () () 6) The questions were relevant to the material in the book Strongly agree Agree Neutral Disagree Strongly disagree () () () () () 7) The questions were relevant to the material in the exams Strongly agree Agree Neutral Disagree Strongly disagree () () () () () 8) You felt the system motivated you to do the homework diligently Strongly agree Agree Neutral Disagree Strongly disagree () () () () () 9) You felt that submitting the homework assignment on the web and receiving immediate feedback improved your

understanding of the material Strongly agree Agree Neutral Disagree Strongly disagree () () () () () 10) You felt that the grading of the assignments was fair and any inconsistencies were resolved Strongly agree Agree Neutral Disagree Strongly disagree () () () () () 11) Any queries, bug reports etc. were promptly and correctly dealt with (leave blank if you didn’t have any queries) Strongly agree Agree Neutral Disagree Strongly disagree () () () () () Please use the other side of this sheet for your comments, -

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A v e r a g e r e s p o n s e V S q u e s t io n n u m b e r

0 .0 0

0 .5 0

1 .0 0

1 .5 0

2 .0 0

2 .5 0

3 .0 0

3 .5 0

4 .0 0

q u e s t io n n u m b e r ,a v e r a g e r e s p o n s e

Ave

rage

resp

onse

(max

=4, m

in =

0)

S e r ie s 1 3 .6 8 2 .3 4 3 .6 3 3 .1 9 2 .9 2 3 .3 6 2 .8 6 2 .5 6 2 .5 2 2 .8 8 2 .8 7

1 2 3 4 5 6 7 8 9 1 0 1 1

Number of students VS average response

0

5

10

15

20

25

0.2 0.6 1 1.4 1.8 2.2 2.6 3.2 3.6 4 More

6. Interpretation of the data and Conclusions The Computerized Homework Assignment Grading System eliminates the need for

homework graders and motivates students to do their homework. It also sets a clearer and higher standard of understanding of the material as the norm for Physics 218. CHAGS is very easy to incorporate into the class syllabus. It is a clear improvement over the current system that has the homework component of the course as optional with no mechanism for feedback. Finally, according to the data from our survey, students' reaction was overall positive (average response 3.5 out of 4.0).

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7. Acknowledgments

We wish to thank Prof. Kenefick who was very helpful in TA-ship arrangements needed for the development of this system. We also wish to thank the Physics Department for its support and the students from Prof. Toback's spring '02 class for identifying bugs and giving valuable feedback that allowed fine-tuning of the system.

8. Relevant web addresses and contact information:

Prof. David Toback has been the driving and coordinating force behind the CHAGS project since its inception in the Spring of 2002, providing direction and securing funding. Joel Walker has developed the software and Andreas Mershin wrote the problems.

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For more information, comments/suggestions regarding any aspect of CHAGS please contact Prof. David Toback (toback@physics.tamu.edu)

For specific information, comments/suggestions etc. regarding the software contact Joel Walker (jwalker@physics.tamu.edu)

For specific information, comments/suggestions etc. regarding CHAGS content or this brochure please contact Andreas Mershin (mershin@physics.tamu.edu)

To take a sample homework, first create an AMES/CHAGS userid/pass at: http://www.physics.tamu.edu/QUIZ/login.html by choosing "sample" instead of section number and then logon to CHAGS at http://www.physics.tamu.edu/QUIZ/view.html/CHAG_CH2 (Change CHAC_CHX to see various chapters (1-14 available) and bring the

Physics 218 textbook with you.)

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http://www.physics.tamu.edu/QUIZ/stats.htmlhttp://www.physics.tamu.edu/QUIZ/view.html/CHAG_CH2