In the photovoltaic tent, visitors got to experience the principle of generating electricity from sunlight. On a black hole model, they spun marbles that raced along orbits on a taut canvas. At the superconducting train exhibit, they watched as it levitated above the tracks and traveled with almost no friction. This was this year's exhibition by the Institute of Physics of the Czech Academy of Sciences (FZU) at the tenth-anniversary edition of the Science Fair (Veletrh vědy), the largest popular-science event in the Czech Republic.
Our exhibit dominated the first hall and became one of the fair’s most popular stops. Visitors could not only view the physical phenomena we presented but also experience them firsthand.
Solar energy, levitation and gravity
The photovoltaic tent was a major attraction for visitors of all ages. Inside, participants (visitors) simulate the Sun supplying energy to “electrons” (balls), which they toss into a “conductivity belt” suspended from the tent’s ceiling. This interactive activity introduces them to photovoltaic electricity generation. Right next to the tent, our solar zoo, an unconventional terrarium full of beetles, grasshoppers, and spiders, was also a hit. They look and feel like they’re alive, but they only move when light hits them. That’s because they’re powered by solar cells attached to their backs.
The levitating train also attracted attention. Its secret lies in a phenomenon called superconductivity, which certain materials enter when sufficiently cooled, in this case, to about −196 °C using liquid nitrogen. The superconductor then levitates (falls infinitely slowly) above the magnetic tracks. As a result, the train hovers and remains attached to the tracks even when traveling upside down. And because it does not touch the track surface, it moves with almost no friction.
Similarly, a gravity simulator, nicknamed the “black hole”, helped visitors understand invisible forces. It works by placing a heavy weight on a taut screen, which creates a depression around it, much like how mass curves the surrounding spacetime. When visitors rolled a ball across the sheet, they could observe its movement along orbital paths and simulations of phenomena such as Kepler’s second law, perihelion precession, tidal disruption, and gravitational waves.
Where the eye can't reach
Great discoveries do not always require expensive, extraordinary instruments. Visitors got hands-on with a diffraction, the same physical principle behind crystallography's role in major scientific breakthroughs, by measuring their own hair using nothing more than an ordinary ruler and a laser pointer. Visitors also got to watch crystals grow in real time from a sodium acetate solution, and even taste the difference between crystalline and amorphous forms of the same material.
Other things, by contrast, can be seen only in virtual reality. Our VR ATLAS placed visitors right inside the giant particle detector, and at the touch of a glowing sphere, it offered a 360-degree view from places few of us ever get to see in real life. ATLAS is one of the largest particle detectors in the world and sits at the international CERN centre near Geneva.
Distinguished guests
Over the course of three days, a diverse mix of visitors passed through our exhibition. Among the first to stop by was Radomír Pánek, president of the Czech Academy of Sciences, followed later by his predecessors, Eva Zažímalová and Jiří Drahoš. On Thursday and Friday mornings, the exhibits were mainly visited by school groups, while in the afternoons and on Saturday, families with children made up the majority of visitors.
We distributed dozens of educational memory games (including our latest set, full of physics discoveries) and comic books to elementary and high school teachers, and invited them to participate in our photo contest and the “Physicists Into Schools” project’s lectures. We also introduced the Karel Výborný Foundation Fund, which can be used to fund short-term study trips abroad for students.
This time, our exhibition had a guest of its own. We invited Wikimedia Czech Republic, a non-profit that develops Wikipedia and runs educational programmes, editathons, photo competitions and partnerships with cultural and scientific institutions.
The successful year was best summed up by Michael Prouza, director of FZU: “The Science Fair is one of the best opportunities for us to show children and adults alike that physics is an exciting adventure. When we see that visitors, both young and old, tend to stay much longer than they originally planned, that’s the best feedback any of us could hope for.”
Our thanks, therefore, go to the more than 130 colleagues who helped prepare the exhibit and enthusiastically tended to it for three days. It is thanks to them that our booths became places where tens of thousands of visitors could not only see physics but also experience it and develop a closer connection to it.
