This post summarizes my continuing pursuit to move lectures from my classes into short screencasts and reading assignments. It was inspired by my participation in the Fall 2012 Teaching with Technology seminar series and has been an ongoing project since that time.
In class, students are making calculations using new equations that I never once wrote on the board. After iterating and refining my approach I am finding that students are arriving in class with the intellectual tools needed to participate in conceptual discussions and solve example problems on their own in class. It’s been eye opening for me.
Instead of writing down equations and performing derivations, I spend class time focusing heavily on the discussion of concepts, facilitated in large part by clicker questions and student-worked example problems. Students spend their time before class watching screencasts, reading the material, and performing rudimentary calculations using equations that are central to that day’s discussion. I incentivize them in two ways: 1. I try to make each class heavily modular, with very specific instructions on which screencasts to watch, which book sections to skip, which sections to skim, and which sections to focus on and aim for a thorough understanding. 2. I assign online reading quizzes that are long-answer and conceptual in nature.
Screencasts are short 5-7 minute videos that record the screen of a tablet computer along with audio commentary. An instructor typically uses them to introduce material, formally describe complex derivations, and work example problems that are more sophisticated than ones that can be effectively solved during a class period.
One of my primary motivations for this project is feedback from students who suggest that I somehow knit the conceptual nature of class time with the problem solving skills needed for the homework assignments and exams. In this regard I’ve found that screencasts are very favorably received. At the end of the Fall 2012 semester I gathered some direct quotes from students, using a survey administered on D2L:
“Having the problem on the screen and the instructor making annotations and arrows as well as writing out equations was extremely helpful in understanding the concepts. The screencasts to me were an extension of lecture, where Professor Knutsen was able to more thoroughly explain and go through a more complex problem. Also, the screencasts were a complement to the textbook, it gave me more practice and further understanding of the concepts I read about in the chapters.”
“I like clicker questions during lecture and screencasts outside of class. Screencasts are a way to go through more in-depth problems at my own pace outside of lecture. Whenever lengthy problems are presented during lecture I tend to get lost and lose attention whereas, if they're presented in screencasts, I can work through them at my own pace.”
“I really liked how the professor could slowly work through a problem step by step in a way that class time just can't afford to do.”
“I like the screencasts for its flexibility, because we can watch whenever and wherever we want.”
“I really like everything about screencasts because they really help me learn how to actually do the calculations to solve a problem. I like the problems that are similar to the homework so that I can watch the screencast and get help solving the similar homework & exam problems. I feel like example problems are what is missing in lectures, but the screencasts make up for that and I think that is perfect because then lectures can be conceptual based. Screencasts are a better solution than working out examples in class because I can do them on my own time and pace rather than following along in class.”
“I like how they can contain a lot of detail while solving a lengthy example problem. These lengthy problems can be tedious in class, but the screencasts help provide the numerical details that are needed to solve the problems. The problems are no longer tedious when I can watch them on my own time, because I can also pause and rewind if I miss something.”
“In class, our professor can't cover all the steps of complicated problem simply due to time constraints. With screencasts, he can go over all the nitty-gritty details that need explaining but would use up too much class time. They have been essential in my understanding of the material.”
This brief screencast also describes some of the benefits of using them:
Why Prepare Screencasts? (YouTube video)
Various types of reading quizzes can be developed in classroom management software such as D2L. Although they take more time to grade, I am a fan of long-answer conceptual questions, such as:
- “Describe a fluid to me. How is it different from a solid? List a few examples of fluid mechanics in everyday life.”
- “What is your understanding of a shear stress? How is it similar to pressure, and how is it different?”
- “Describe to me a velocity gradient (some people also call it a shear rate).”
- “A flat, 10 cm by 10 cm square plate slides over another flat plate, separated by a film of fluid that is 1 mm thick. The viscosity of the fluid is 10 Pa-s. The velocity profile of the fluid is linear. What force (in Newtons) is required to move the upper plate at a speed of 10 cm/s? You don't have to, but typing some work will help justify partial credit.”
I assigned these questions prior to the first day of class. Question 1 provided a great deal of material to foster a discussion on why engineers might want to learn fluid mechanics. Questions 2-3 required students to re-assimilate what they just read. Question 4 is a relatively simple calculation, but one that definitely required some conceptual understanding of the material. What I found remarkable was that the wide majority of students correctly solved Question 4 before we even met for the first time. It suddenly became clear to me that I did not need to “cover” things in class to ensure that students learned it. They were learning this stuff on their own.
Incentivizing students to actually watch the screencasts and accompanying reading assignment can be time consuming, especially for 50 minute class periods, which meet 40+ times each semester. It does require preparation several days in advance (barring this need, I often prepare my classes less than two hours prior).
To make this strategy work, consistency is very important. I’ve found that at the beginning of the semester I’ll prepare reading quizzes and assignments for each day of class. However, as the semester progresses, my quiz writing and assignments become more intermittent, and students don’t know what to expect. They then view reading quizzes as a surprise chore that could hurt their grade instead of a useful tool.
The following are some suggestions from students:
“Sometimes the screencasts went too fast and I could not keep up. Luckily I can pause them quickly, so that really isn't that much of an issue. However, because of the speed, I could not understand the problem statement and I would get really confused. I think the beginning of some screencasts should be slowed down and be a little more descriptive on what is going on to start it off.”
“[Screencasts] should have been more promoted. I did not know them until the end and I really regret not seeing them before.”
“Unlike in lecture, a screencast cannot answer questions on the spot. By the time I might get to the professor, I will likely have forgotten my question or found more pressing things to ask.”
“I didn't like the fact that they were the only real example problems worked out for us. So, I felt as if we were required to watch them to have any idea how to work problems similar to homework and exams.”
“Knowing that there are screencasts available makes me lose focus in class because I know I can always just go back and watch a screencast.”
I consider this the last comment a success. By providing students the means to revisit concepts after class with a fresh perspective, I have made their lives easier.