Chemistry Reference
In-Depth Information
9.1 The Criteria in Relation
The criteria of concreteness and of connection are fundamental to the PIN-Concept
right from the beginning. As the knowledge system grows, the other criteria that
regulate the learning process become more and more important. However, the more
global criteria of supporting cognitive skills and of scientific enculturation require
long term and continuous efforts in reasonable contexts. It should be noted,
however, that we do not implement these criteria in randomly replaceable contexts,
but in the course of problem-solving and conceptualization processes that the
growing knowledge system demands. These processes need to be built upon each
other without gaps and to proceed step by step. The whole curriculum is laid out for
continuous cognitive training and for the establishment of an empirical attitude.
This can only be achieved, when all mentioned criteria are being used, but not one
to the detriment of another.
In the following, one possible way will be described to explain the methodology
of the PIN-Concept by example. The further development of the PIN-Concept,
including possible variations and combinations of single components as well as
options for the educational reduction and for the integration of interdisciplinary
aspects and connections to everyday life, is described in the topic “Organic chem-
istry education according to the PIN-Concept” [
1
].
9.2 Sorting Unknown Substances with Unknown Reagents
The identification of six unknown pure substances A-F is the focus of this unit.
These are all colorless liquids, which will be labeled later. To gather information
about them, they will be compared by means of tests under standard conditions with
the help of six reagents, which are also unknown at first ([
1
], S. 295). The results
will be displayed in a matrix (Fig.
9.1
, see color chart).
It might seem unusual to try to gain information by a combination of unknowns
with unknowns. This method was even recommended by the famous chemist Justus
von Liebig, who wrote in his popular chemical letters in 1844 ([
40
], S. 11):
“We study the characteristics of bodies, the changes they suffer, when coming
into contact with others. All observations together form a language. Every charac-
teristic, every change that we discover on the body, is a word in this language.
The bodies show relations to others, they resemble them with certain characteristics
or they differ from them. These differences are as manifold as the words of the
richest language are. In their meaning, in their relation to our senses they are
not less different. But to be able to read this topic with its unfamiliar ciphers and
to understand it, one has to get to know the alphabet first.”
Liebig advises to thoroughly study the “ABC of phenomena” first (see Figs.
9.1
and
9.2
), till sufficient similarities and differences between the unknown substances
have been found on the phenomenological level. In this way, students discover that
