CHEMKON
Titelbild (R. Peper): Das Foto zeigt den fertigen, aus Guarkernmehl hergestellten Slime. Dieser Slime ist von gummiartiger Konsistenz und hinterlässt kaum Spuren an den Händen bzw. Gegenständen. Je höher die Konzentration an Guarkernmehl ist, desto viskoser wird der Slime. Mit Lebensmittelfarbe kann er beliebig angefärbt werden. Im Artikel (siehe Seite 179) wird aufgezeigt, wie beispielsweise Slime...
Goldruby glass is considered as key to chemical nanotechnology. In this contribution methods of coating are described using gold doped alcoholate‐solutions for the sol‐gel process. The dip‐ and spin‐coating processes were achieved professionally and by low‐cost‐methods. The surfaces were examined by spectroscopy and ellipsometry.
Following legislative changes a re‐categorization of various boron compounds has been made, which are relevant for experiments in chemistry class. Commonly used compounds, such as boric acid, diboron trioxide and borax are of particular concern. Out of uncertainty teachers might exclude experiments which use these chemicals. Our paper presents five classical school experiments with boron compounds...
The chemical language is an important link between content knowledge and communication skills in chemistry. It is a learning goal in its own, but additionally it represents chemical processes and concepts according to precise rules. However, numerous studies have revealed remarkable difficulties of students concerning the interpretation and use of chemical symbols, formulae, and reaction equations...
In a practical class that is a compulsory part of their major subject biology A level pupils from a grammar school in Lower Saxony worked on the topic of ‘esters used as fragrances’. Under the given conditions at school the pupils’ objective was to synthesize pure esters which were then sensorial tested by their classmates. The following article has been collaboratively worked on by the pupils and...
Titelbild (M. Ducci und S. Zajonc): Das Foto zeigt verschiedenfarbig fluoreszierende Flüssigkeiten. Hierzu wurde schwarzer Knetgummi auf eine Glasplatte gebracht und mittels entsprechender Zahlen und Buchstaben einer Magnettafel Vertiefungen ausgestanzt, in die die Flüssigkeiten gefüllt wurden. Die Bestrahlung mit der UV‐Lampe erfolgt von der Unterseite der Glasplatte. Zu den Ursachen der unterschiedlichen...
The article focuses on zeolites as examples of modern materials in school chemistry. After an overview of the structure and the structural building units of zeolites, the syntheses of two zeolites are described. These can be performed with basic chemicals without large equipment in a solvothermal‐like reaction. Ideas regarding the identification of the products as well as subsequent experiments are...
The stokes shift is the distance between the wavelength which results in maximum absorption of radiation of a dye, and the wavelength with the maximum emission of light. A large stokes shift is beneficial at fluorescence spectroscopy. In this article, this phenomenon will be demonstrated using the example of pyranine from marker pens. The result will be discussed in a student friendly manner using...