In an exciting lesson, Prof. Tom Nilges presented experiments that were not only educational but also astonishing. The children learned how to handle chemicals safely and important safety rules. One highlight was smelling ammonia: with great care, the students experienced the characteristic odor of this substance. They were then amazed to see how a nearly colorless liquid turned deep blue with just a few drops of ammonia. This effect, caused by the reaction of ammonia with an aqueous copper(II) solution, left many wide-eyed.
When asked what they imagined chemistry to be, the students promptly answered with phrases like, “something that smokes, bangs, or stinks.” Well-prepared, Prof. Nilges demonstrated an experiment that met these expectations perfectly: with red phosphorus and potassium chlorate, he created a reaction that was triggered with a snap of his fingers, resulting in a loud bang. The children were so enthusiastic that the experiment was repeated outdoors. There, a larger amount of the substances was mixed on paper and set off with a hammer blow, producing a spectacular explosion! At the same time, Prof. Nilges emphasized the importance of caution, especially with unknown substances and reactions.
After this thrilling part, everyone calmed down with a series of experiments involving liquid nitrogen. The students watched in fascination as the extremely cold nitrogen formed tiny droplets when poured onto the warm ground, which quickly evaporated. Some children speculated about what was happening and observed how the nitrogen turned into gas.
Another highlight was a balloon filled with liquid nitrogen. Magically, it grew larger and larger until it eventually burst with a loud bang! Next, colorful plastic balls from a ball pit were dipped into the nitrogen. The once-elastic balls became rock-hard and shattered when thrown against the wall – an unexpected effect that amazed the children.
To conclude, Prof. Nilges had a special surprise: he dipped a rose into liquid nitrogen and demonstrated how it crumbled into dust when touched – a fascinating gift for the school principal. The session ended with a spectacular finale as the remaining nitrogen was poured onto the wet ground, filling the terrace with dense “smoke.” Thankfully, the fire brigade wasn’t called!
Further information and links:
- Public Outreach
- Prof. Tom Nilges, Professorship of Synthesis and Characterization of Innovative Materials
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