FEd Fall 2001 Newsletter - Motivating Students to Learn Physics Using an Online Homework System

Fall 2001



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Motivating Students to Learn Physics Using an Online Homework System

John Risley

The Issue - A major task of physics teachers is to encourage students to solve physics problems. Traditional tools such as textbooks, lecture time, tutorial centers, and tests can help, but more creative effort is required to give them the practice they need to master new concepts and applications. Although we identify important problems for our students to consider, assign a schedule, and answer questions to help guide them through the intricacies of an expert solution, students are reluctant to expend the time and energy required to complete the work.

If these assignments are not graded, at best the students will simply look over the list of problems. We can tell students that solving these problems will help them on tests, but in reality little is done except last-minute cramming the night before the exam. Routine assignments with deadlines are necessary for most students to learn physics. But this work must be graded if it is going to encourage students to spend time working through the exercises. Grading is a chore, and many teachers simply do not have the time or resources to grade papers carefully.

This critical grading task can be virtually eliminated by using online homework grading systems. Students will receive immediate feedback, and instructors can offer more frequent, shorter assignments to keep students up to date on the course material.

A robust, multifeatured system with a richly endowed question database is critical to successful online grading. One such system is WebAssign, a web-based homework delivery, collection, grading, and recording service available to teachers, professors, and instructors who want to provide more effective encouragement to their students learning physics, see http://webassign.net.

WebAssign - WebAssign delivers, collects, scores, and records student work. Teachers make up assignments by using their own questions or choosing questions from leading physics textbooks. WebAssign is a project in the department of physics at North Carolina State University (NCSU). It is supported by a team of programmers, content specialists, editors, designers, and instructors. New features and improvements are deployed continuously to provide the best possible assessment system. Agreements with textbook publishers are in place that allow WebAssign to deliver problems from class-adopted textbooks. New agreements are sought continuously as new textbooks and editions are published.

The origins of the WebAssign code stem from work conducted by Larry Martin, a physics professor from North Park University in Chicago, and Aaron Titus, a graduate student in physics education research at NCSU. Larry Martin wrote a comprehensive web-based homework system using a flat file architecture. He created the tag, which is a way to incorporate powerful Perl functionality into questions and answers. This tag allows you to randomize numbers, variables, and many other programming features such as logic statements, define variables and arrays, etc. In May 1996, Aaron Titus created a web-based assignment system using a database of questions and answers delivered by a Macintosh server. This system was used with 300 students at NCSU. Martin and Titus collaborated in 1997-1998 to develop the basic functionality of the current WebAssign system. This merger led to a very robust, multi-featured application.

Many individuals are involved with WebAssign so that the features instructors want can be added to the system. A high level of responsiveness demands a concerted effort by faculty, programmers, editors, and technical support associated with the project. WebAssign is offered as a fee-based subscription service to teachers at universities, secondary schools, and educational institutions to provide viable funding for this work.

WebAssign offers many key features that are important for physics teaching. The most significant is the quality of its question types. Numerical questions can be randomized with answers that depend on the calculated values, and even answers that depend on values that the student enters. Students receive the same set of questions, but each will have different values. Symbolic questions allow a formula to be entered, again with randomization of numbers and variables. Java applets, such as the Physlets from Wolfgang Christian at Davidson College, can be deployed to offer a very different kind of problem to solve. These simulations bridge the gap between questions about a static drawing to a laboratory measurement, while maintaining the advantage of automatic grading. A file-upload question type is available for grading Excel spreadsheets, Word documents, a MatLab worksheet, or any other type of file. Multiple-choice, multiple-select, and fill-in-the-blank questions are also available.

All questions in WebAssign can utilize Martin's powerful <equ> tag, which allows a teacher to write code in Perl and have it evaluated in WebAssign. This important development also enables teachers to write questions that can analyze students' experimental parameters and their resulting calculations. With the full power of a programming language hidden just beneath the question, physics teachers can offer all sorts of logical statements and conditions for questions and answers.

A hallmark of WebAssign is its extensive database of questions from leading physics textbooks. In WebAssign, it is easy to create elaborate multipart questions, which can represent exactly the questions found in textbooks. Coding questions is an intensive task, requiring careful attention to detail and accuracy. An incorrectly coded answer algorithm can cause much grief with students, so the WebAssign team responds quickly when these kinds of problems arise. WebAssign supports textbook questions with a quick turnaround time for reported error. This responsiveness sets WebAssign apart from other online homework systems.

The questions coded into WebAssign are virtually an exact replica of the original question, using the same figures and pictures that appear in the textbook. As teachers, we know how easily the scope of a question can change with just a slight alteration in wording. By working with leading publishers ,WebAssign has taken a strong position on providing the very highest quality set of textbook questions.

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WebAssign's Publishing Partners

WebAssign offers numerous student communication links for the teacher. In addition to offering the capability to email one student, a group of students, or the whole class, WebAssign has a "help desk" that allows students to request help with a specific assignment. A teacher can respond to these questions efficiently because a full display of the assignment, along with the student's responses and correct answers, is available from the help desk. This is much better than having students send you an email about an assignment that you then have to look up!

Reporting grades is an important component in a teacher list of responsibilities. WebAssign shows all scores, down to each individual problem, for any and all assignments. All of the relevant statistics are available for any question or assignment, such as average, mean, max/min, standard deviation, or index of discrimination.

One Example - Each teacher can adapt WebAssign to suit his or her particular needs. This is what makes WebAssign such a powerful tool. For example, I will outline how Bob Beichner and I use WebAssign for both of our introductory calculus-based physics courses at NCSU. This course is taught in the SCALE-UP classroom with the able assistance of Jeanne Morse, my TA. (Our more typical lecture courses with laboratories also make heavy use of WebAssign, but without the added advantage of having computers in the classroom.)

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Each week we assign two homework problem sets. They are due one hour before class. (We have found that midnight deadlines don't work, since many students start the assignments in the middle of the night, and a deadline too close to the start of class results in students coming to class late!) On Mondays, the assignment consists of three to four easy questions from the textbook, usually focusing on new material that we have not covered in class. This forces students to read ahead and prepare for the upcoming class. Students are certainly better prepared now. The Wednesday assignment covers the more difficult questions and might have four to six questions. At the start of each class, we often have lively discussions about the homework. For students who had difficulty, these discussions bring them up to speed and they usually ask for an extension to resubmit their work so they can get a perfect "100." I generally allow extensions. I want to encourage my students to spend more time learning physics, and with WebAssign an extension doesn't require any more time from me to grade their work. (WebAssign easily facilitates extensions, and you are notified whether or not the student has seen the answer key.)

On Fridays, we give in-class quizzes using WebAssign. We have a classroom filled with computers so the task is very efficient. WebAssign has security controls that allow you to restrict access until a password is given in class and allow only certain computers access based on IP subnets.

We often have in-class activities, similar to a laboratory, but shorter. To encourage students to think about the work before coming to class, we post a prelab assignment on WebAssign that is due before the lab. The formal lab is a group effort, written in Word or some other word processor. Any member of the group can upload it into WebAssign as a file-upload type. The TA is able to read the electronic reports, assign a score in WebAssign, and give comments to the group that become a permanent record for each student. We also assign a few problems about the lab that can be graded automatically. WebAssign allows you to create automatically graded questions that ask the student to enter their measured values, assess them for reasonableness by setting a large tolerance, and then use their measured values to calculate some physics property. The essential data taking and analysis can be graded accurately and automatically. If you give students multiple submissions, they can correct mistakes made during data acquisition as they complete the analysis portion of the lab. It is also possible to freeze the acquired data in one assignment and then use that data in the analysis section so that students are less likely to fudge their results!

Computer simulations are a very effective way to get students to interact with physics concepts. The trouble, though, is that students will not use the simulations effectively unless you ask them some leading questions that can only be answered through careful observation. If you do not ask students to turn in their observations for grading, the students do little work. We have used a number of java applets for in-class activities that are graded either on the spot or just after the class is over. Again, by automatically grading the students' work, you can be certain that they have been engaged in the learning opportunity.

Finally, we use WebAssign for high stakes testing. Here, the benefits of automatic grading are obvious. For a typical 50-minute exam, we deploy about ten questions, many with subparts. They range from very simple calculations and multiple-selection conceptual questions to difficult computations. To encourage students to think hard about the content of the test, we allow two "free" submissions. This way, if students make a simple mistake in their calculations, they can correct it with the second submission. To encourage struggling students, we offer additional submissions but with a loss of 3 points, out of 100 maximum, for every additional submission. We are happy with the results. Students who know the material receive high scores and those who are not putting in the appropriate effort get low scores. Student surveys indicate a high degree of satisfaction of WebAssign tests over our standard multiple-choice tests.

We recognize that our use of WebAssign is not entirely typical. However, we have seen that it saves time while motivating students to do the work. What more could we ask?

John Risley, professor of physics at North Carolina State University, is well known for his research on the utilization and effectiveness of computer technology to teach physics. He is editor of Physics Academic Software, a cooperative effort with APS, AIP and AAPT, and he is director of WebAssign. His email address is: John_Risley@ncsu.edu