Interview Christian Schaffner: flipping the classroom with Modern Cryptography
For the first time this year, Dr Christian Schaffner, assistant professor at the Faculty of Science’s Institute for Logic, Language and Computation (ILLC), taught Modern Cryptography as a third-year course in the Computer Science Bachelor’s programme. Christian teaches the course using a flipped classroom approach. The students prepare for the working sessions by watching videos and completing quizzes beforehand. During the working sessions, they get to grips with challenging problems. An experiment with Canvas, the new digital learning environment, provided the perfect vehicle.
‘I first taught Modern Cryptography as a Master’s course for a smaller group. I initially used a conventional classroom setting, but then switched to a flipped classroom approach. I used Moodle for this purpose. I was therefore pleased to find out that I could experiment with Canvas for the Bachelor’s programme. Christian Majenz and Jan Czajkowski helped me to prepare and teach the course. We had counted on around 20 to 30 students. In the end, however, 56 students sat the exam. We were unable to find a suitable lecture hall to hold working sessions in this manner for such a large group.’
How does the flipped classroom approach work?
Christian explains that ‘the concept of a flipped classroom is that your students prepare the material in advance, after which you jointly process the material in class by using it to solve problems. The Modern Cryptography course entails two working sessions a week of two hours each. Students are required to prepare for each class by watching three or four videos from the Coursera course Cryptography by Jonathan Katz. They then complete a quiz composed of reading questions in order to check their comprehension. During the working sessions, the students work on problems and questions. At the end of each class, the students are given a homework assignment to complete and submit within six days.’
Modules for each working session
‘Canvas offers modules that enable you to order your course logically. We offer one module for each seminar, divided into preparation, working session and homework, in that sequence. This starts with a reference to the chapters from the book and the videos, which the students can use to prepare for the working sessions and complete the associated quiz. Next, a link is provided to the problems from the working sessions, the homework assignment and the bonus material.’
How did the experiment go?
‘The two of us converted the existing Moodle course into Canvas. I had participated in the user tests when a new learning environment was being chosen, so I already had some experience with Canvas. Canvas is very intuitive, and if you can’t find something, you can easily search for it and find an answer in the Canvas forum. The conversion process went well. We did, however, have to re-enter the formulae wherever these appeared in the questions. Fortunately, Canvas offers the option of entering mathematical formulae using LaTeX.’
The students could ask questions in the discussion forum. ‘Their questions were answered by us within one or two days. There was quite a bit of action in the forum. Unfortunately, we saw that very few students answered each other’s questions. We had really hoped to stimulate crowdsourcing through student discussions. This will require a shift in student mind-set.’
No more terrible handwriting
‘We compiled quizzes for the homework assignments, enabling the students to submit their work in the form of essays in Canvas. They could also enter and submit formulae in Canvas. Digital submission saves time because you don’t have to decipher illegible handwriting.’
‘For the programming assignment, we wanted to use the Canvas peer review and rubric functionalities. It was not entirely clear how those worked. We wanted students to work in groups and then evaluate the programs of the other groups. The students first had to join a group and could then submit the assignment as a group. However, some students preferred to work alone. In order to review the assignments of others, students first had to submit their own assignments. I had created a rubric with five sections; 0, 1 or 2 points could be given for each section. The students also had the option of giving feedback for each section. However, many students are lazy and would rather just give the highest score without comment. The rubric functionality in Canvas is also a bit “buggy”. We’ll be looking into ways to improve this next time.’
Flipping with Canvas?
Christian indicates that Canvas supports the ‘flipping the classroom’ approach very well. ‘Canvas could make a significant contribution towards new forms of learning. A lot of educational material is already available, for example in massive open online courses (MOOCs). Enabling students to learn at their own pace, in their own time and with their fellow students really is very beneficial. A modern Learning Management System (LMS) like Canvas is absolutely necessary for this. As a lecturer, you have to think carefully about the added value you can offer and what you hope to achieve through face-to-face contact. For example, my students had access to all the material online, except for the solutions to the problems, which we discussed during the workgroup sessions.’
Advice to other lecturers?
Do you have any advice for lecturers who are still getting to grips with Canvas for the first time? Christian responds spontaneously, ‘Just ask me! It’s not that difficult to work out how to use Canvas for your course, but it’s fun to help one another to find the best way. For example, it’s not that difficult to put a quiz in place for students to test whether they understand the subject matter fully. Stimulating student discussions could also add value to your course.’
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In this report, Christian describes the process of flipping the Modern Cryptography course for Master’s students (English).
Christian Schaffner is assistant professor at the Faculty of Science.