Countless life forms in the universe
“Teachers who make physics boring are criminals.” With this quote, the famous physicist and former MIT professor Walter Lewin summarizes the meaning of his lectures. To many, Dr Lewin is the Bob Ross of physics or the man who brought physics into the home of the average citizen, with his experiments popularizing the complex laws of physics and being viewed over 100 million times online, while in 2007, he featured on a New York Times front page in a piece titled “At 71, Physics Professor Is a Web Star.”
Kathimerini spoke with the distinguished academic and co-author of the book “For the Love of Physics” in a discussion about the ever-changing landscape of education, the need for creative teaching time as a key ingredient for understanding the course of physics and future discoveries in the field. However, Lewin does not limit himself to a trivial discussion but elaborates on some of his famous experiments, such as the “pendulum experiment,” which won him the title of the internet’s most recognizable physicist.
Professor Lewin, how has the landscape of physics education changed over the years and what trends do you foresee in the future?
E-learning has permanently changed the concept of physics education. I was among the very first to explore e-learning. My lectures had been video-recorded at MIT and were shown in the halls of MIT, but also on a TV station in Seattle, which reached out to 5 million people. And that was already in 1995. It is worth mentioning that Bill Gates lives in Seattle; he watched my lectures on TV and wrote me twice about that.
You can now watch almost every physics lecture online that you can imagine. You can now even pass courses online and get credit. Therefore, it is true that e-learning has totally changed the whole concept of teaching, which started in a classroom and now it is not even necessary to be taught in the classroom. It is worth mentioning that nowadays students can ask questions on my YouTube channel and receive answers.
In your book “For the Love of Physics,” you explain the fundamental principles of physics in a simple and understandable way. What led you to simplify your science, what are some effective strategies for making complex physics concepts more accessible to students?
I was able to explain difficult issues using simple words and simple examples, often referring to the students’ own world and their own experiences. And of course, I support physics with demonstrations. Some of them were mind-boggling, even dangerous. So that the students will never forget them. I can make the students stop breathing, I can make them totally silent or laugh, and I can even make them wet their pants. And that is true! I am not joking. My lecture style is rather unique.
In my lectures, I put emphasis on the beauty and the excitement of physics, rather than on the details that would often be lost by students anyhow. I always try to, where possible, make my students see things that they have never thought of before, but are within reach of touching. My goal is to make them love physics and to make them look at the world in a different way. “Why are the skies blue, why are sunsets red and why are there rainbows?” And that is for life. What counts is what you uncover, not what you cover.
At universities, professors usually teach difficult and complex mathematical variables, but you try to popularize the knowledge through your experiments. Based on your famous quote “Teachers who make physics boring are criminals,” I would like to ask how you balance rigor and depth with fun, and what advice would you give to educators looking to create engaging content for their students?
Well, the advice that I am going to give them, they may not like because a lecture is like building a “house.” It is all a matter of time spent in preparation, and of course, it is a matter of the teacher’s imagination. Preparation time for each of my 94-course lectures was about 60 hours per lecture. When I gave that lecture for the first time, I would have to stop my research and concentrate exclusively or almost exclusively on my lectures for two terms. Of course, that was very hard on my graduate students.
As mentioned before, a lecture is like building a “house.” I would think for many days, even longer than that on the layout of that “house.” I would dry-run my lectures three times (two weeks before the lecture, one week before the lecture, and at 6 a.m. on the day of the lecture). This led me to have near-perfect timing and never have to rush through a demonstration, as many other professors do, who never timed their lectures. Trust me, I have attended many physics lectures at MIT by my colleagues, nine out of 10 times they run into great problems. In the end, they were planning a demonstration, but they lacked time so they rushed it. Therefore, my advice is to think of each lecture as building a house that has to be beautiful, comfortable, and exciting. It is a must to dry-run the lectures. If needed more than once to avoid that the lectures are falling apart near the end. With all due respect for my 100 physics colleagues at MIT, only a handful were great teachers.
In one of your famous videos you lift a ball up to your chin and release it. Natural forces do the rest. Can you explain what prompted you to do this experiment which has been well received by your millions of digital followers?
The pendulum experiment was a very famous demo where I stood with my back against the wall, so I could not go back – that is the key. I stood with my head against the wall and I held a 5-kilogram object at the end of the pendulum against my chin and then I would release the ball so it would swing away and it would come back at me. It would make a complete swing and end up roughly a millimeter from my chin. This was a classic that is used nowadays at many universities, but I added the Lewin touch to it. I built up the pressure by telling the students that I could not sleep all night because if I made a small mistake, namely giving it a teeny-weeny little push this could be my last lecture. I also told them that I was afraid and I would therefore close my eyes. All of this was building up the tension. Of course, the whole thing is totally harmless because of the air resistance. It never touches your chin, but it comes always very close. However, it is true that if I would give it a little push, then yes, it could kill me. So, I asked them to be very quiet and to make no noise. I would then count down, “Three, two, one, zero,” and I would keep my eyes closed until I would feel the wind again of the incoming ball. The students would sit frozen in their seats, because they really believed, “Well, maybe this is his last lecture.” So, this is all drama, and that drama stays with them for life.
Are there any particular areas of physics that you find particularly exciting or that you think hold great promise for future exploration?
We still do not know what dark matter is, and we do not know why there is dark energy. The normal matter that we see is the matter of stars, planets, gas, animals, trees, and you. That is only 5% of the total energy in the universe. 27% is dark matter and 68% is dark energy. This is an area that holds great promise for the future, certainly for the scientist who first can demonstrate what dark matter really is. We still do not know that and that surely will include Nobel Prizes in the future.
Conclusively, what future discovery would you like to be ahead of when it happens?
I would love to be present and still alive when life is discovered outside our solar system. Of course, there is no doubt about the existence of countless forms of life in our universe. That is not a maybe. A very rough back-on-the-envelope calculation that many can make is that there are 100 billion galaxies in our universe and each galaxy has about 100 billion stars, and on average they have about 10 planets each. And if we now assume that only one in 10 million planets have forms of life, then there are still 10 to the power 16 planets with forms of life in our universe. Therefore, it is not a maybe, but an absolute must. And yeah, it is likely that sooner or later there will be conclusive evidence. However, the problem is the distance. Even the closest stars are four light years away from us, and they may not have any life.
