Kinder-Uni: Of Quanta and Cats

10/07/2025

The Würzburg Kinder-Uni (Kids Day) starts on Saturday, 18 October, with a lecture by physics professor Ralph Claessen. It's about the crazy world of quanta and a cat.

Physics professor Ralph Claessen shows what Kitty Q looks like. (Image: Hannah Genheimer / Universität Würzburg)

Imagine a spinning top that turns left and right at the same time - sounds crazy, doesn't it? But in the quantum world, this is exactly what is possible.

This world offers many more surprises: Things can be in several places at the same time - but only as long as we don't look so closely. Tiny particles sometimes behave like little balls and sometimes like waves on the water - depending on how we look at them.

What sounds like magic or a science fiction film is quite normal for quantum physics. Physics professor Ralph Claessen will explain this at the Würzburg Kinder-Uni on Saturday, 18 October 2025. Children aged between 6 and 13 are invited to the university on Sanderring to immerse themselves in the world of quanta with the professor and to think, marvel and learn together.

Cat Q in the Gaming Lounge

Ralph Claessen uses small experiments to show how differently the rules work in the quantum world. The children learn in a playful way what this world is all about. And they get to know the famous Kitty Q cat, which is both dead AND alive - some children may already know it from the mobile phone game of the same name.

If you haven't heard of the multi-award-winning game yet, you can get to know it at the Kinder-Uni: This time there will be a special gaming lounge in the atrium. Kitty Q was developed at the Würzburg-Dresden Physics Cluster of Excellence ct.qmat.

Participation and Registration

Admission to the Kinder-Uni is free. If you want to be sure of attending, you should book your ticket in advance on the Kinder-Uni website .

The lecture is in German language and lasts half an hour. It is held once at 10 am and once at 10.45 am. The children listen in the Audimax, for adults and older siblings the lecture is transmitted by video to lecture theatre 166.

Contact: kinderuni@uni-wuerzburg.de

The Next Kinder-Uni Dates

(all in German language)

13 December 2025

Greek and Roman heroic stories
Prof. Dr Jorit Wintjes, Chair of Ancient History

25 April 2026

Satellites in orbit and how they become space debris
Prof. Dr Marco Schmitt, Chair of Computer Science, Sensors and Embedded Systems for Earth Observation, and Prof. Dr Mohamed Khalil Ben Larbi, Chair of Computer Science, Space Informatics and Satellite Systems