One of the more unusual components of my fall cryptography course was the cryptography timeline I had my students create collaboratively. Inspired by the collaborative timelines put together by the students of Brian Croxall and Jason B. Jones, like this one on the Victorian Age, I asked my students to enter events from the history of cryptography into a Google spreadsheet, adding dates, descriptions, images, and links for those events. The back-end code then pioped those events into a nice online, interactive timeline I’m hosting here on derekbruff.com. Students’ contributions to the timeline earned them credit toward their class participation grades. (See Brian’s great tutorial for instructions on setting up your own timelines using the same free tools.)
In contrast with how quickly my students jumped into social bookmarking, my students were much slower to contribute to the class timeline. As of October 7th, seven weeks into the semester, my students had contributed 36 items to the class Delicious feed, but only 11 items to the timeline. Four of those timeline contributions came from the same student, and nine of my students hadn’t contributed to the timeline at all. Over on Delicious, all but two of my students had tagged something, with an average of 2.4 items bookmarked per student. The average for the timeline was 0.73.
I see two main reasons for the slow uptake in timeline contributions: One is that adding an entry to the Google spreadsheet that feeds the timeline takes more work than bookmarking a website in Delicious. The other is that I didn’t take class time to bring up the timeline and interact with it. This meant that there weren’t clear connections between the timeline and the rest of class, turning the timeline activity into something like “busy work.”
I had a good reason for not bringing the timeline into class discussions early in the semester: A timeline doesn’t seem very useful to me when it doesn’t have a lot of entries, and, early in the semester, there wasn’t much on our timeline. Once a timeline has a lot of entries in various categories (like that Victorian Age timeline I mentioned above), it can be a rich source of data to analyze for patterns and trends. The catch-22 here is that by not discussing the timeline in class, I de-motivated my students from contributing to it!
On October 19th (week nine of the semester) I decided to try and change that dynamic. I emailed my students before class and asked them to bring their laptops and their copies of our textbook, The Code Book by Simon Singh. During class, I asked them to take 15 minutes to make as many contributions to the timeline as they could. I told a third of the students to focus on events from the first chapter of Singh, a third to focus on the second chapter, and a third to focus on the third chapter. (We were about to start Chapter Four, so this worked out well.) There were still several students who hadn’t contributed to the timeline, so I spent the first five minutes of this time period showing them how to access the Google spreadsheet. The students were remarkably productive after that, however, doubling the number of entries in the timeline to that point by the end of class! It was fun to see so many people updating the same Google spreadsheet in real time.
Although I didn’t have time to have the students analyze the now-useful timeline during class, I did ask them to take a look at it for homework. Here’s what I asked them to respond to on the course blog:
Take a look at the crpytography timeline you’ve built as a class. What insights about the history of cryptography occur to you as you examine the timeline? How could the timeline be improved to make it more useful to you, particularly as you think ahead to your “big questions” paper at the end of the course?
Here are some of my students’ thoughts about the timeline at this point in the course. (You can see the rest of their thoughts on the course blog.)
- “Now that the timeline is becoming more developed, I am beginning to see some relationships between what is happening during certain periods of history and the development of cryptology. For example, some of the greatest feats of cryptography have occurred during times of war.” (Several students noted this correlation.)
- “One trend I see is that there tends to be a lot of activity surrounding technological innovations such as the telegraph, the Difference Engine, and the Enigma machine. The advancement of cryptography is accelerated by the advances in other areas of science.”
- “I find it interesting to see how many categories we have. Cryptography is a subject that touches many others, which is something that some people don’t think about.”
- “The timeline shows the exponential advancement of cryptography. Between the first example of cryptography (2000 BC) and 1500 AD we have 5-10 events… [But] we have found at least 30 events that occurred in the past 500 years. The Renaissance, development of communication, and technology have led to significant advances in cryptography.”
As for ideas for making the timeline more useful, students mentioned having more events on the timeline, finding ways to illustrate connections between events, and having more tools available to search and filter the timeline.
These comments showed me some of the value in constructing and analyzing a timeline like this one. And the in-class activity spurred more students to contribute to the timeline during the second half of the semester, I think. Of course, two weeks later I specified exactly how many contributions the students needed for full class participation credit. That probably helped, too!
By the end of the semester, the timeline had 121 entries in seven different categories (ciphers, culture, people, unsolved, and so on). Every student had made at least three contributions, with an average of 8 contributions per student. And although students didn’t receive credit for more than 12 contributions, two students went above and beyond, logging 13 and 16 contributions, respectively.
Several students weighed in on the timeline in their end-of-semester feedback survey responses:
- “The timeline was, for me, the best tool to help draw connections because you could see how different things related to each other. It also provided a place to go when looking for examples for papers.”
- “The collaborative time line is also important in that the time it took to create gave insights into cryptography that the Delicious feed never would have been able to.”
- “The timeline was less helpful, simply because it was less visible, and almost redundant of lectures and readings, but it was also a neat visual representation of how far cryptography has come.”
- “I was not so crazy about the timeline. I only accessed the information when adding my own events to the google doc. While it is interesting, I never encountered a situation when I had to use it as a resource.”
So the timeline received some mixed responses from the students. I’ll add that one of my survey questions asked students to identify which outside-of-class participation activity was most helpful to their learning. Only one student identified the timeline as most helpful; all the others pointed to the pre-class reading discussions on the blog and the social bookmarking activity on Delicious.
One of my next steps in making sense of this course is to take a close look at my students’ final papers and look for evidence that they drew on each other’s contributions to the course, including contributions to the timeline. Once I’ve conducted that analysis, I’ll be in a better position to assess the impact of the timeline in this course.
In the meantime, however, I have a few thoughts on making the timeline more useful next time around if I chose to use it again. One is to take some class time earlier in the semester to have students contribute to the timeline, perhaps when we get to the end of the first chapter. Getting students over the hurdle of contributing their first item to the timeline will be important to do early.
Another is to have the students analyze the timeline for patterns and trends as part of a formal outside-of-class assignment or a more informal in-class activity. I like the observations my students made about the timeline back in October, and I’d like more of them to engage in that kind of thinking. I’ve been thinking about ways to have students write more frequently in this course (beyond the three big paper assignments), so perhaps I could have them develop a claim based on their analysis of the timeline and write a short essay defending that claim using the timeline entries as evidence. I would want some discussion here, too, since I think some of the claims are debatable. (For instance, the student’s observation above that cryptography has advanced “exponentially” is problematic, and not just because the word “exponential” is used differently in mathematics than in general use!)
The current version of the timeline could use some editing, too, so one option next time is to simply have students analyze and revise the current timeline, instead of adding entries, at least at first. The timeline is already a bit unwieldy with more than 120 entries; adding more entries might not make it more useful without some serious editing.
Stay tuned for the results of my analysis of my students’ final papers. Until then, I would be glad to hear your thoughts on my timeline experiment or your own uses of timelines (collaborative or not) in your teaching!