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Wednesday, March 2, 2011

Heat

A physics textbook definition of “heat” would be something like “the spontaneous transfer of energy due to a temperature difference”. It is a process, not a state. This is to be made distinct from temperature and internal or thermal energy. I consistently drill the definition of heat into the heads of my students, but I feel that I am fighting an uphill and possibly useless battle for several reasons:

  • The everyday use of the term is usually as a state. Dictionary.reference.com defines it as “the condition or quality of being hot.” The terms heat, temperature, and thermal energy are interchangeable in the minds of most students.
  • Engineers and chemists often use the term as both a state and a process. Though they would not equate heat with temperature, I don’t get the sense that the strict physics definition is being reinforced in other classes.
  • Certain terms in physics cause confusion. “Specific heat capacity” is an especially annoying one.

To sum, I see our own field as somewhat muddled and inconsistent, related fields as very inconsistent, and everybody else as completely confused. While we must struggle with definitional inconsistencies all the time (our “velocity” is more specific as it includes a direction and our “acceleration” is more general as is it includes slowing down and changing direction), I find that “heat” is by far the toughest to resolve.

Eugene Hecht has been tackling these issues. He has published letters or articles in The Physics Teacher on problems with the definitions of “energy” and “mass”. I can only hope he’ll read this and set the matter straight.

Friday, November 19, 2010

Cheating

The Chronicle of Higher Education recently published an article by a writer who works full time writing papers for students. This began while the writer was in college and eventually became this person’s job. What disturbs me is how pervasive this cheating might be and how easy it apparently is for students to get away with it. While this particular type of cheating is more obviously directed towards wealthy students in the humanities and social sciences, I certainly consider cheating a problem in all fields.

There were a huge number of replies to this article, some of which focused on blame. The students are to blame. The students present the work as their own. This is academic fraud. Yes, the writers ought not to sell papers for this purpose. And yes, professors/instructors/teaching assistants ought to be more vigilant against cheating.

Here are some things I do to prevent cheating:

  • Individually randomize given data in online homework
  • Write some of my own homework problems
  • Write all of my quizzes and exams
  • Never give multiple-choice quizzes or exams
  • Individually randomize given data in some quizzes and exams
  • Require a large percentage of the points to be earned in my presence (labs, quizzes, exams)
  • Require proctored exams for online courses
  • Require photographic evidence for online lab work
  • Obvious stuff like forbidding cell phones as calculators, watching students during exams, and comparing work between assignments and among students

Here are some areas of concern:

  • The rooms we use are generally pretty full. This means that students sit in close proximity while taking quizzes and exams. When I was a teaching assistant at Oregon State University, we used gigantic lecture halls and put an empty seat between each student. I don’t think this is feasible at Chemeketa.
  • Proctors for my online students appear to vary in their vigilance. I really have no reasonable way of vetting my proctors other than requiring them to be at a testing service at an accredited college.

Sunday, September 12, 2010

Back to School

After a year of leisure, I’ll soon start teaching full time again. I took unpaid leave to finish an MFA in creative nonfiction writing and although that wasn’t exactly “time off” my hours were spent concentrating only on me: my writing, my projects, my submission, my homework, my classes. Soon, I’ll be back in my teacher role where it is always all about the students--as it should be.

As a community college teacher, I’m well aware that most of my students work close to full time while trying to keep up with a full course load. Many of them also have families. This week—-a week before the regular quarter starts--I taught a module at my school’s First Year Introduction (FYI) seminar about how to succeed in science classes. FYI is like a booth camp for students who feel they aren’t quite ready for college student life and need learn a little about successful student behavior. I started the module by telling the FYI students the same I tell my regular students: the college curriculum load assumes you spend two hours outside of class on preparation and studying for every hour you spend in the class room. That means that for a five credit class, you spend a total of fifteen hours per week on just that subject. If you take three of those classes, you’re all of a sudden up to 45 hours per week of just school work—more than a full time job. To be able to have a life on top of that, you have to figure out a way to beat the system—a way to study more efficiently and be able to cram ten hours worth of outside classroom studying into eight or fewer hours.

I taught my module at 2.30 pm and at 7 pm. In the first class, most of the students were straight out of high school. As I went over the importance of preparing for class, why they would be frustrated if they fall behind in a science class (the concepts build on each other), and gave them practice exercises on how to effectively read a college textbook, they stared at me with glassy eyes, texted friends that were not in the classroom, and chatted with each other about current movies and video games. I had to dig deep into my arsenal of basic classroom management skills to be able to conduct an effective class. Five minutes before class was over, all of the students were gathering up their books, zipping up bags, and had one leg posed to sprint up from the chair and out the door. As I gathered up my handouts and erased the whiteboard, I wondered if I should ask for another year off. I had obviously forgotten how to be an effective educator.

Before the later module began, I ran errands and stopped by the grocery store to pick up something to eat for my dinner. I also loaded up on cookies for the students. My plan was that if I didn’t get them excited about taking science, at least they would remember my session’s sugar high with fondness. If you can’t reach them through knowledge, try food.

The students that filed in through the door shortly before seven were a little bit older than my previous group. When they saw the cookies they exclaimed things like “awesome” and “I’m totally going for double-stuffed Oreos.” During my presentation, they stopped me several times to ask questions about what science classes were available on our campus, who the most popular instructors were, and why you have to take biology before zoology. They loved the textbook reading exercises and a few of them asked for my email and office number in case they needed further study tips after the quarter starts. At the end of class, most of them stayed behind to ask more questions about which science classes I thought might be right for them.

It was an awesome session. I drove home remembering how great it is to be part of students discovering something new and interesting. How privileged I feel whenever a student’s passion for science is awakened. I also remembered the reason I went into teaching in the first place was because I want to show students how much fun science can be and that everybody is born a scientist. We start our early years in life investigating the world around us, recognizing the patterns of it, and figuring out how to function within it better—just like scientists. That evening I felt good about teaching again.

I suspect the second batch of my FYI groups consisted of students a little more mature than the first, a little more motivated and a little more independent as learners. I probably did a better job of presenting the material since it was the second time around that day. However, I’m not taking any chances and come first day of the fall quarter, I’ll be walking in to class armed with a batch or two of cookies.

Hope your back to school week is a good one. How are you psyching yourself up for the start of it?

Monday, August 30, 2010

Clickers, Questions, and Clicker Questions

One innovation that has infiltrated physics education over the last ten years or so is “clickers”. These are little devices that students use to remotely enter answers to multiple-choice questions presented by the instructor. I see several possible goals for their use:

  • take attendance or use in assessment (mini quizzes)
  • help students to pay attention and to promote active learning
  • help students to evaluate and to improve their understanding
  • allow instructors to assess average understanding for the students and to adjust lectures accordingly

One drawback I have found to clickers is that there is a significant cost in time or money to students, instructors, and IT. I have adopted a low tech solution where I simply use colored and lettered cards. This obviously prevents the first goal from being achieved, but that is not an important one to me.

Some of my questions are on my website or linked to the University of Maryland physics question of the week. I project these during lecture while others I simply write on the board. I try to give about half a dozen of these “clicker questions” during every 50 minute lecture. Ideally, these questions require some deep thought, though sometimes they are of the nature of “which kinematics equation should I use to solve this problem?” Most students really seem to enjoy the more interesting questions and learn from them. One student even reported that he had been given one of my clicker questions during a job interview!

At the summer 2010 AAPT meeting, I had the opportunity to learn about many resources for “clicker questions”. I was particularly impressed with the University of British Columbia's website where they provide guidance on effective use of clickers as well as links to clicker questions. I will expand my database of questions and re-evaluate the way I use these questions during lectures.

On a related note, I attended a workshop on alternatives to traditional problems. One idea presented was “context-rich problems” which are realistic, complex, and interesting. The University of Minnesota Physics Education Research Group can be contacted for some of these. Other ideas presented at the workshop included “Jeopardy problems” (students write questions to given answers), ranking tasks, questions with more than one solution, questions that cannot be answered with the given information, and questions with wrong answers provided (students must correct the answers). I like these ideas and I intend to implement them this academic year.

If anyone has additional links to clicker questions or non-traditional problems, please let me know.

Friday, August 13, 2010

Burning the Midnight Oil @ Bunker Hill Community College

Bunker Hill Community College in Boston, MA offers midnight classes. In this article, a columnist from Inside Higher Ed who taught one of those classes describes the experience. The Bill & Melinda Gates Foundation made a short movie about that.

Sunday, August 8, 2010

Textbook Alternatives

I think it is reasonable to assume that community college students are especially sensitive to price. Price is one of the advantages of attending community college over a public or private four year college. But the sticker price of community college (tuition and fees) is less than students actually pay because of the significant price of textbooks. The current edition of Knight’s textbook costs $225 new, for example. While this does include access to an online homework system and the students can potentially sell back the text at the end of the year, this is still a large amount of money for most of my students. This problem has even drawn the attention of Congress, which passed a bill requiring disclosure of prices to instructors, unbundling of supplements, and early notice to students of required textbooks.

I recently joined a “Textbook Advisory Committee” at Chemeketa for the purpose of reducing these costs. We gathered ideas from faculty and our bookstore, met with book salespeople, and published recommendations. Here are some of our ideas:
  1. Use the same textbook when multiple instructors teach the same course.
  2. Use the same textbook for courses in a sequence.
  3. Coordinate with instructors at other schools to purchase textbooks as a group.
  4. Use 3-hole drilled or custom textbooks. Publishers like these because they stifle the used book market. In return, they are generally willing to give a lower price.
  5. Negotiate with the publisher to obtain discounts.
  6. Use an online textbook (e-book).
  7. Use old editions or accommodate multiple editions.
  8. Use self-authored, creative commons, open source, or materials that are not copyrighted.
  9. Put textbooks on reserve in the library.
  10. Use book rental.
My current strategies include 2, 7, and 9. I use Knight’s first edition which runs about $10 on Amazon. I’m also interested in open source materials. But as long as students can find the old textbooks (which I like), it doesn’t seem worth the effort to cobble something together.

I would appreciate comments on the above ideas. I’d also like to hear about ideas you have that are not on the list.

Portland Phun



As Karim detailed, the TYC Physics community had a phine time in Portland. In addition to the marshmallow launcher competition videos Karim posted, here's one that shows some of the building process:



This workshop was intended to immerse the participants in the project-based milieu. I've presented multiple contributed and invited presentations about Project-Based Physics (and several posters), but there's nothing like actually doing it to try it on for size. Here is the document used to guide the activity.