Special prize "Jugend forscht"

"Reaction Paths of Ferrocene and Troticen" As part of his project, the sixteen-year-old Spors succeeded in demonstrating the link between theory and chemical practice in an outstanding way. Dominik Spor's favorite subject has always been chemistry. He is particularly fascinated by reactions in which organic and inorganic chemistry meet, for example in organometallic complexes. Some of them show the typical behavior of aromatics such as benzene, but at the same time, due to the central metal atom, also properties such as so-called diamagnetism. Using ferrocene and troticen as an example, the young chemist investigated how complexes react with other metal-containing or organic compounds and analyzed the products with the help of mass spectroscopy. He found that the two chemically similar compounds differ unexpectedly in their reactivity. (c) Jugend forscht e. V.

"Why does iron sulfide synthesis whistle?" As part of their project, Ali Karaca, Björn Bankowski and Daniel Lamonski succeeded in presenting the link between theory and chemical practice in an outstanding way.

?If you put sulfur powder and iron wool in a test tube and heat the sulfur, you may hear a whistling sound. We wanted to deal with this phenomenon. In all relevant textbooks one can read that the clay is created due to the strongly exothermic reaction. We were critical of this statement and wanted to know the real reason for this phenomenon. To do this, we proceeded step-by-step: First, we succeeded in generating a reproducible sound by optimizing the initial experiment. Then we examined how the tone was influenced by changing individual parameters (iron wool: length and structure, test tube volume, test tube opening).

The result of this series of tests was that the audio frequency changes due to the parameters mentioned. We also found that the test tube is the sound box of the sound. By preventing the chemical reaction between sulfur and iron, we were able to show that a whistling sound is also produced here and thus the reaction is not the reason for the sound being produced.

Based on these results, we developed the following theory: The rising sulfur gas stream is broken at the iron wool fibers and thus causes pressure fluctuations in the test tube, which ultimately generate vibrations that can be heard as sound. This corresponds to the principle of sound development in a recorder.

In further experiments we found that the clay can also be produced without the use of sulfur. From this we concluded that this is a physical phenomenon, the thermoacoustic effect. This is based on the thermodynamic cycle in which the air is made to vibrate due to temperature differences above and below the iron wool. ?(C) Nachrichten aus der Chemie

"The focus of our work was the vitamin C stress in the kitchen," said Timo and Thomas. And so they demonstrated, among other things, that in an aqueous solution the loss of vitamins after standing for four hours was already over 10 percent and that vigorous stirring (oxygen exposure) and heat are particularly effective vitamin C killers. The losses were enormous, especially when heating in a pressure cooker. The addition of cyclodextrin, a permitted food additive, was able to reduce losses by over 80 percent at higher temperatures. The students not only analyzed the vitamin C content, but also the spatial structure of the host-guest relationship between cyclodextrin and vitamin C. They also called the topic of their work ?News from the molecular kitchen: Cyclodextrin protects vitamin C?. And they also had products from their molecular cuisine on offer at the national competition from May 21 to 24 in Osnabrück: self-pressed orange juice, pasteurized kiwi juice and jams made from mango and kiwi.

"Synthesis of Opals" For the first time since 2003, the German Chemical Society (GDCh) has again awarded a special prize at this year's 43rd national competition "Jugend forscht". The award was given to a work in chemistry that particularly successfully combined theory and practice. The winning team, Felix Brunner, Raphaela Baumann and Johanna Kaltenbach from the Georg Kerschensteiner School in Müllheim (district of Breisgau-Hochschwarzwald) received the special prize of 1,000 euros for the successful synthesis of opals using simple means. "I was impressed that this team of students has succeeded in producing artificial opals with the simple means available to a school, solely on the basis of very good theoretical knowledge of Materials Science and intelligently carried out experiments," said the former GDCh president with admiration Professor Dr. Henning Hopf after the award ceremony on May 24th. This is a nice practical example from chemistry with everyday relevance, which almost has a craft character. Overall, Hopf was very pleased with the high level of the presentations at the national ?Jugend forscht? competition, which took place in Bremerhaven from May 22nd to 25th.

"Diffusion speed in aqueous solution" Anyone who drinks their coffee with milk is familiar with the phenomenon that Julia Drehmer, Angela Marx and Kathrin Brandt dealt with. Without the influence of external forces, coffee and milk mix to form a homogeneous liquid. This so-called diffusion is caused by the independent and disordered movement of ions, atoms and molecules. The students were interested in whether the mixing takes place at a certain, unchangeable speed. To do this, they investigated the diffusion path of permanganate ions and copper (II) ions at different time intervals. Result: The diffusion speed depends on the type of ions and their concentration. The place and time of the mixing process also play a role. (c) Jugend forscht e. V.