From charcoal kiln to orbital model

By Ulrich Wunderlin, October 2013

Chemistry is located between physics, which deals with inanimate objects, and biology, the science of living things which is concerned with the structure of living creatures and their chemical metabolic processes. The actual chemical part concerns the transformation of substances. But in the course of the twentieth century the process aspect has increasingly receded into the background. “Thinking in tiniest particles” (molecules) dominates chemistry as a science today. Chemistry teaching in Waldorf schools deliberately takes another path.

Picture: © Charlotte Fischer

Chemistry lessons in Waldorf schools start with everyday experiences and the most important discoveries in industrial use. Entry to the subject follows the historical development of chemistry. This is the focus of teaching; material science and process science are treated with equal importance. Chemical experiments by the teacher – as well as the experiments undertaken by the pupils – play a decisive role in the development of knowledge which always starts with observable phenomena. Key chemical processes form the basis for understanding substances and processes. That chemical processes have their origin not in the inorganic world but in living organisms belongs to the fundamental concepts which anthroposophy can contribute to general education. This basic thought is of exceptional importance particularly in our time of ecological disasters. The language of chemical formulae is developed on the basis of experiments and chemical processes. In contrast to conventional teaching of chemistry, it is not introduced until later, namely once pupils have a soundly based overview of the chemical processes arising from direct experience, reconstruction and step-by-step penetration with the thinking.

In the beginning was fire (class 7 to 9)

The first central chemical process is fire: the path via gaseous waste swirling in the air to the acids and via the ash residue to the bases is pursued, followed by neutralisation and saltification. Through heat and charcoal – obtained in a charcoal kiln – as new chemical tools we find our way to the metallic elements which underlie the bases. Through the combustible metals, the non-metals which underlie the acids can be obtained as elements: phosphorous from bone ash with the help of magnesium, hydrogen from water with the help of red-hot iron. The polarity between lime and silicon is the focus in the third part and includes a study of the soil. Calcium oxide from weathered stone and lime are able to bind carbon dioxide or sulphur dioxide, while silicon with the toxic heavy metals (the ashes) can form on the one hand coloured glass and on the other essential minerals. We appeal here to thinking in cycles and important basic thoughts of ecology are tackled.

The substances which build up the body of the plant form the content of the second main lesson. The starting point is the polarity between the combustible, blazing fats and the carbohydrates which only glow. We characterise the fats in the chemical processes in which they can engage as substances which are insoluble in water but which can be transformed into water-soluble products when treated with a strong lye (saponification). In contrast, the carbohydrates such as starch and cellulose can be transformed into water-miscible sugars through treatment with acids. The proteins, which can have both an acidic and alkaline action, are treated as the balancing middle between these two polarities. In the third main lesson, the focus is on the organic substance of the body and their catabolic processes. Just like the fire process represents the key in mineral chemistry, so partial microbial digestion represents the key to the organic secondary substances. Fermentation of sugar produces alcohol, the “fire water”. This substance can be transformed in three separate ways. If we deprive it of chemically bound water, its fiery characteristics are enhanced – ether is even further removed from life than alcohol. If, in contrast, alcohol is “ventilated” (reaction with oxygen, oxidation), we get acetic acid which is closer to life. If alcohol reacts with acid, esters are formed in an anabolic reaction; they are frequently scents. The breakdown of protein takes us to the amino acids and biogenic amines. On the one hand, these play an important role as messengers in the body and on the other they are the starting point for the synthesis of important drugs (alkaloids). In the first three chemistry projects, we work on an overview of the substances which arises when we follow basic chemical processes. The substances are treated in line with their importance in nature and in organisms.

Conceptual deepening and penetration (class 10 to 12)

In class 10, we pick up mineral chemistry again. But now the work essentially revolves around finding the appropriate concepts for the various chemical processes and the principles by which they are ordered. If heave metal salts are allowed to react in a solution of silicate, a bizarre colourful underwater world suddenly grows. In contrast, osmosis in the simplest single-cell organisms living in freshwater does not lead to destruction as in an inorganic experiment but to an ordered flow of water determined by the organism. In saline solutions, parent bases and acid residues are always only latently present. They are not revealed as independent substances. In order to come closer to their nature, we experiment with electrolysis. That takes us to the use of chemical formulae and simple stoichiometry. The term “particles” appears for the first time.

In class 11, the content of physiological chemistry is penetrated with the thinking. Here the functional groups of classic organic chemistry reveal themselves to be very suitable for classification purposes if their possible processes are taken from what is living. The central chemical concepts give us new access to these functional groups. The path to the acids goes via the aldehydes and ketones to the carboxylic acids, an enhanced acid path can be found in the sulphonic acids.

The path to the bases is shown on the one hand by the alcohols, the amines, then the heterocyclic compounds (aliphatic and aromatic rings with bound, reduced nitrogen) and, finally, the alkaloids (caffeine). In class 12, a complete overview follows which summarises chemistry and its connection with the geological and physiological processes. The polarities of the families of elements in the periodic table are discussed. The metal processes are brought up and their importance in the proteins and reactive centres of the enzymes is discussed. Mineral, plant and animal chemistry are brought together and their differences worked out. If we can manage to place the silver and gold processes at the end of this chemistry main lesson we end with a picture which can give us an idea of a new processuality. The formation process of colloidal gold can be an image for the birth of the human being (“the human being enters the earth through the gate of gold”), the formation of reflective silver an image of the moment of death at which life is experienced in reflected images (“the human being leaves the earth through the gate of silver”).

The particle world

In terms of content, we build in class 10 on the question of the totality (the system) and its components (the particles). Here it becomes clear from all the examples we look at (the Daniell cell as the basis for the battery, an organism or a molecule) that the totality is always more than the sum of its parts. It becomes directly apparent that we cannot say that sulphuric acid (H2SO4) “consists” of two hydrogen atoms, one sulphur atom and four oxygen atoms. The atoms precisely give up their identity as individual particles when they enter into a compound. In this way we can begin to work on the foundations of atomic structure. The model level is included so that certain characteristics can be derived, for example the valency of an element in a compound.

But here it is important always to distinguish whether we are referring in our description to the substance level or whether we are characterising the featureless world of particles – a water molecule does not have density, no melting or boiling point. These two levels simply cannot be linked with a mathematical operation as is frequently still thought (simply multiply by the factor 6.023 · 1023 – that only works with gases). If we take it further (e.g. in an advanced course) it is fascinating to retrace the path in our thinking which led Niels Bohr to his atomic model (1913). He starts from the observations of the hydrogen spectrum and Rydberg’s simple mathematical calculation of the spectral lines and attempts to describe them in terms of physics. In doing so, he has to make assumptions which cannot actually exist in classic mechanics and electrodynamics. Yet he makes them and introduces quantum theory into the description (stationary states of the electrons in the atom). By making these assumptions, his model of the atom is not actually a model but a continuative research programme. Quantum theory is quickly replaced by quantum mechanics which then leads to the development of the orbital model (Heisenberg’s matrix calculation, Schrödinger’s wave function calculation). This model can provide an explanation for many phenomena which cannot otherwise be understood but the mathematical ballast which is concealed behind it is immense. That is the one side. But the other side shows that the naïve atomism of antiquity which continues through Dalton is no longer tenable. On the contrary, the approach of quantum theory makes clear that material reality is a totality which is not constructed from individual particles. In experiments, we divide up this totality and describe individual phenomena which must, however, be placed back in the context of the totality. That in particular is of great importance with regard to describing the particle level and leads away from the naïve idea that the points we see on a scanning electron microscope are, at last, atoms become visible.

To avoid the danger of too much mathematics, it has shown itself to be productive to supplement the work on the orbital model with an overview of the primary and secondary substances of living things in accordance with their physiological formative processes. This results in a surprisingly simple overview of the key substances. The principles of classification make use of qualities of the substances which relate to their formation and function in the organisms. Thus the salt-like substances deposited by the organism and the sulphuric substances with their future reaction potential form a polarity. In between we have the mercurial substances acting directly in the present and involved in a constant process. Substances can be described in different ways. We apprehend the substance with its physical constants and its molecular structure (formula schema). We understand the formative processes in the organism which have led to the precipitation of this substance. Substance level and particle level come together, are understood as two sides of a totality. We learn about the past of the substance, how it has become what it is. If we then ask ourselves on the basis of our  knowledge of the physiological processes what we can do with this substance as human beings capable of cognition and action, what its future potential is, we are able to understand a substance in its entirety. If we can look ahead to what might happen in future through our transformation of this substance, we may – this is the great hope – no longer introduce substances into nature without knowing what they might lead to. We learn to anticipate the future consequences of our present actions.

About the author: Dr. Ulrich Wunderlin is a biology and chemistry teacher at the Atelierschule Zurich.