Impressions from
KölnerKinderUni 2024

Welcome to the 2nd Physics

With Daniel Rosenbach

About nanotechnologies –
but how small is nano?

The Size-Sorting-Challenge

On cool computers –
but how cold is cold?

The Temperature-Challenge

Cool experiments
with liquid nitrogen

Exciting technologies at the Cologne Children’s University

Cool Technologies, Cool Materials, Cool Computers, Cool Experiments


Under the motto “Cool Technologies, Cool Materials, Cool Computers, Cool Experiments,” this year’s event of the Cologne Children’s University took place at the II. Physical Institute. Daniel Rosenbach, a postdoc in the Laboratory for Quantum Electronics, took the curious students on a fascinating journey through the world of quantum physics and quantum materials for quantum computers.

Daniel demonstrated how technologies developed at the institute require tiny building blocks – nanoblocks, to be precise. He challenged participants to sort various objects by size and explained the principle of lithography using the world’s smallest soccer field. Afterwards, students learned how the behavior of materials can change through cooling and how these changes can be utilized for various purposes. By using liquid nitrogen, he vividly demonstrated how balloons shrink and rubber ducks shatter.

In another challenge, students were asked to sort objects by temperature. A particular puzzle was a cryostat from Daniel’s lab, which, with only 0.01 Kelvin, was not only the coldest object but also known as Cologne’s most complicated refrigerator. This refrigerator can control and measure quantum chips, a research project in which Daniel and his colleagues are intensively involved. Students also learned that quantum computers can perform computations practically impossible for conventional computers and learned the difference between a quantum bit and a classical bit.

To conclude, students had the opportunity to witness various objects being cooled in liquid nitrogen (-196°C) and the different effects this had – the highlight being the super-cool popcorn.

The Cologne Children’s University was initiated by the university in 2003 and is conducted as a cooperative project by various Cologne universities and scientific institutions affiliated with the Cologne Science Roundtable (KWR). Through this collaboration, the Cologne Children’s University offers a wide range of science-oriented events for children from the third to sixth grade, including lectures, workshops, and occasionally long-term projects.


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