What made you want to promote scientific concepts?
I have been a big consumer and enthusiast of popular science since I was young. I started reading Science et Vie (Science and Life) magazine when I was in secondary school. Then, gradually, I read all the popular science magazines. After that, from the fourth or third grade onwards, I regularly made the trip from Chartres to Paris to spend whole days at the Palais de la Découverte (the Science museum within the Grand Palais). So there was this desire to give back so many things that had motivated me.
How has this promotion work been perceived by your peers and your laboratory?
I'm lucky enough to be in a laboratory where it was seen in a positive and benevolent light (the Kastler Brossel laboratory (LKB)). Colleagues saw it as a good thing because it didn't encroach on my research activities. In other words, as I said, it was the cherry on the cake, but I always made sure that the cherry didn't replace the cake. Beyond the time involved, this promoting science work had to be of a quality worthy of the laboratory.
You've been doing this for over 20 years. What changes have you noticed?
The first thing is that promoting topics to the general public is more widely practiced and more widely seen. You can see that a lot of young people are getting into it, whereas in my day there weren't many of us. There's also more recognition at institutional level. For example, the CNRS, at the instigation of the French Ministry of Research, has created the Medal for Scientific Mediation in 2021, of which I was the winner in the first edition.
At the "On the Shoulders of Giants" festival, you'll be hosting a rather special conference where your audience will have to come in swimsuits...
Yes, thanks to the organization and support of the festival, we created "Physics at the Pool". It was an idea we had 30 years ago with my colleagues Roland Lehoucq (astrophysicist at CEA) and Édouard Kierlik (professor at Sorbonne University), but which we'd never been able to put into practice. Simply because the idea was to bring together the public and mediators to conduct experiments in a swimming pool, the organization and logistics were complex. With the support of the festival's organization team, we were able to set up this activity last year, and we did it again this year.
In concrete terms, at "Physics in the pool", everyone is in the water, because the idea is to experiment and feel things. To make the link between physics and sensations. There's a section on buoyancy where we have bowling balls, some that float, some that don't because we use balls for amateurs, all the same size, but with light balls for children (2.5 kg) that float very well to heavy ones (8 kg) that sink instantly.
There's also an optics sequence. For example, there's a classic experiment in which a pencil is dipped at an angle into a glass of water, and the impression is created that the pencil is broken at the surface of the water. We do this experiment with a lifeguard's pole. So it's much more surprising.
We're also going to study the optical effects of light refraction: the fact that when light passes from one medium to another, it changes direction.
After the pool, festival-goers could also head to the funfair, for what kind of experiences?
For "Physics at the funfair" (Physique à la fête foraine) , we were looking at the notion of force: what forces do we feel when we're on a merry-go-round? We have an application (phyphox) that gives access to the sensors, and in particular to the accelerometer, which enables us to measure accelerations and the forces we feel. There's a funfair in Le Havre at the same time as the festival. We'll also be using bumper cars, so we'll be studying shocks.
Not all the groups will be on the merry-go-round at the same time. This means that there will be both one person inside the ride, to feel things out, and one outside the ride to see what's going on. From a physics point of view, this is really interesting. It's what we call changing frames of reference: being able to discuss the same physical phenomenon from different points of view.
What's next for these participative learning projects?
This is the first time we're doing "Physics at the funfair", so the idea was also to experiment, to see how people react, what they feel, and to be able to evolve. For example, for "Physics at the pool" this year, there will be some changes compared with last year. We came up with ideas once we were in the water with people, and we're starting to pass on what we've developed to physics teachers or mediators. In all these things, there's everything you can prepare beforehand and then once you're out there, with the people, it opens up other perspectives.
Jean-Michel Courty, Physicist, Sorbonne Université
This article has been translated into English from The Conversation under the Creative Commons license. Read the original article (in French).
