11 August 2021

Teacher of the Year pens limericks and gifts framed butterflies to his students


Physicist Troels C. Petersen is an academic rock star! In just a few years, his statistics course at the Niels Bohr Institute has become SCIENCE’s most popular offering, a course that attracts students from across the University of Copenhagen. The reason? He loves to teach and values instruction as highly as his own research. Along with his Teacher of the Year Award 2021, he will receive 75,000 Danish kroner.

Troels C. Petersen teacher of the year at SCIENCE 2021
Troels C. Petersen teacher of the year at SCIENCE 2021. Photo: Emilie Thejll-Madsen.

Mounted on the wall behind Associate Professor Troels Christian Petersen's desk at the Niels Bohr Institute are 20 butterflies under glass and frame. On the back of each frame is a five-line limerick that the Teacher of the Year at SCIENCE 2021 has composed for each of the master’s thesis and doctoral students that he has supervised through to completion.

"They receive a butterfly when they have earned their wings, while I keep one for myself. I think it's a nice way to remember those students who one has spent a considerable amount of time with. I remember them clearly and try to keep up with what they’re doing today. The list of former students who have landed important jobs addressing some of the world's great challenges is getting longer year after year. It gives me the feeling that me and the department are doing something right," says Petersen.

Poetically, the butterflies illustrate perfectly the dedication, enthusiasm and connectedness that the 46-year-old particle physicist feels for his teaching and students, which has now earned him the Teacher of the Year Award at the University of Copenhagen’s Faculty of Science (SCIENCE).


Developed North Campus’ most popular course

Troels C. Petersen's eye for instruction sprouted while at the University of California, Berkeley for a year.

"At Berkeley, I realized that my Danish physics education was good. But one day, my supervisor asked me about some incredibly simple statistics. After spending an hour trying to find a solution for something that ought to have taken me five minutes, I discovered that there were holes in my education. It was an eye-opener," Petersen recalls, adding:

"With regards to science, being able to understand data is crucial. Statistics is a basic tool that can help one reach conclusions and determine whether you've discovered something new in your experiment or if the result was just a coincidence."

This revelatory moment prompted the young physicist to develop a course at the Niels Bohr Institute in applied statistics back in 2001, (as a graduate student) upon his return to Denmark. At the time, there were 15 participants in his applied statistics course, all of whom were from the Niels Bohr Institute. After several years abroad as a researcher, Troels returned and resumed the course in 2009. The course now has 168 participants, making it the most popular offering at the North Campus.

"I’m surprised about the continuous growth in interest. While this has caused various snags with classroom assignments and exercise teachers, I don’t cap registrations. In my years out in the world, I was never denied a course offering, something that I’ve always been appreciative of. I promised myself to remember that if I ever had to teach," explains Troels C. Petersen.

This year’s Teacher of the Year offers another recent course as well – machine learning – which is already enjoying great popularity among students. As with statistics, he spotted a new area that, in the digitized landscape of the future, should not just be understood by computer scientists.

Contributed to discovery of the Higgs particle

When not teaching, Troels C. Petersen researches experimental particle physics, i.e., exploring the universe’s building blocks. Back in 2012, along with his colleagues from the ATLAS experiment, Petersen helped discover the famous Higgs particle, an achievement that made global headlines. His research continues to occupy him greatly, both with regards to the exploration of the Higgs mechanism and in the general use of machine learning in physics.

What do you think about researchers who see their teaching as something secondary and less important?

"One needs to recognize that teaching isn’t something that can be simply sprung over. It’s a vital task that has the potential to have a major impact on the development of our young talents. However, I think that there are good developments happening. Whereas people were once employed entirely for their research, their teaching counts as well now," says Petersen.

Have any exceptionally good or bad teachers inspired you?

"I've had very different types of teachers. So really, at both ends of the spectrum. I had one teacher that the news media wrote about upon his return to Denmark, where I really prepared and read up on the course in advance. It turned out that this person hadn’t prepared their instruction at all, which was a disaster. I was really disappointed, but the experience made me all the wiser," he says.


Never missed a lecture in 12 years

Perhaps the aforementioned experience played into Petersen’s own work as a university lecturer. He is certainly not the unprepared type and has never missed a lecture in 12 years, or experienced equipment failure or other type of crash. During the COVID shutdown, where he was forced to teach via Zoom, his thorough preparation and abundance of energetic charisma became even more important in dealing with the new situation.

"I have often been told that I explain my subject with great enthusiasm. And, it was a great help to reach out to students on Zoom. At the same time, I was glad that it wasn’t my first time teaching the course, because the entire process required significantly more on my part," he says.

Have you ever experienced something going very wrong in your teaching?

"Well, I’ve lost a Zoom link or two, but fortunately, nothing 'serious'. However, I do receive ongoing feedback from my students, where there are both compliments and criticism. For example, I brought some COVID-19 data to the statistics course exam, because statistics has been used so extensively throughout the pandemic. In their evaluations, three students responded that they found it somewhat depressing to complete COVID-19 related exam assignments. When more than one student writes the same thing, there are probably a few others who feel the same way but don’t mention it. This will be corrected for next time," says Troels C. Petersen, who also sits on the Danish State Serum Institute's expert group for COVID modelling.

What do you think of students today compared to your own generation?

"Young people have become less idealistic about physics, but more idealistic in terms of wanting to solve the world's challenges. I just thought physics was great when I began my studies. Today, there are many who are driven by wanting to go out and solve problems. For that, physics is an incredibly good tool," he says, adding:

"The absolute majority of students are awesome. They show up with a desire to learn and great enthusiasm. It is the greatest privilege to stand in front of 100 young talents who want to learn what you are teaching. That's the closest one gets to being an academic rock star.”

Along with the award, Petersen will receive DKK 50,000 to develop his teaching and DKK 25,000 as a personal honorary gift that will be presented to him at a reception on 12 August 2021.


Troels Christian Petersen
Associate professor
Niels Bohr Institute
University of Copenhagen
Mobile: 26 28 37 39
Mail: petersen@nbi.ku.dk

Michael Skov Jensen
Faculty of SCIENCE
University of Copenhagen
Mobile: 24 26 82 96
Mail: msj@science.ku.dk