The Johnstone Triangle - Science-Education-Research

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The Johnstone Triangle: The Key to Understanding Chemistry

Norman Reid, Emeritus Professor, University of Glasgow

One of the modern insights is that we can interpret and make sense of so many aspects of learning at all levels simply by considering the nature and function of the working memory. What Johnstone established nearly 40 years ago was the central place of limited working memory capacity in making sense of the difficulties our students often have when seeking to understand chemistry. What was more exciting was the way the insights his research revealed were able to help to predict what would make understanding more accessible.
Reid, in 'The Johnstone Triangle'

'The Johnstone Triangle' is a volume in the Advances in Chemistry Education book series published by the Royal Society of Chemistry

Publisher description ('blurb'):

Chemistry is often seen as a difficult subject to understand. This book focusses on the triangle model that Alex H. Johnstone developed in the early 1980s. Originally conceived in the context of making chemistry more accessible to a wider range of learners, the model has been applied in almost every area of education in chemistry at all stages of learning.

In looking at why chemistry is difficult, there are two central questions. Firstly, does the problem relate to the nature of chemistry and, secondly, does it relate to the way humans gain understanding? Both were found to be important and the answers to the two question were found to be connected.

The triangle model arose from sustained research into human learning. The central finding from research is the critical role of working memory and the model rationalises so much evidence from chemistry education research as well as the repeated experiences of teachers of chemistry at all levels. In order to understand chemistry, it is essential to develop sound mental models of molecular reality. It generates major implications for the way a chemistry curriculum should be constructed and the processes of teaching and learning in chemistry when the goal is focussed on understanding the key ideas. Some of these implications are developed and pointers offered to more successful ways forward.

The power of the Johnstone Triangle lies in the way it offers clear directions for all involved in chemistry education. It is hoped that this book will prove helpful to all involved in sharing the exciting story of the way humans have come to understand the molecular world, one of the great examples of great human endeavour

Chapters:

1. The Working Memory Story: Why Is It Difficult to Understand Chemistry?

[This chapter can be downloaded as a sample for free at https://pubs.rsc.org/en/content/ebook/978-1-83916-168-1]

2. The Central Role of Working Memory: How We Handle Information

3. Johnstone's Triangle: Why Chemistry Is Difficult

4. Johnstone's Triangle and the Curriculum:
Making Chemistry Accessible

5. Johnstone's Triangle and the Learning Process:
Making Understanding Accessible

6. Releasing Understanding: Three Broad
Approaches to Teaching

7. Tips and Tricks: Practical Ways to Develop Teaching

8. Bringing It Together: The Model and Chemistry Teaching
and Learning

Subject Index

Some selected quotes:

to give a flavour of the book…

"There are important lessons for all teaching chemistry: if we do not fill our working memories with unnecessary information, then it is more likely for us to have enough working memory capacity to be successful in the task given to us. Working memory capacity for any individual is fixed. The question is whether field dependency [re-the skill of being able to screen out important, but irrelevant, information] can be enhanced in any way. If that is possible, then understanding chemistry will become easier."

"[Johnstone] noted how chemists can see things at three levels. We see materials in terms of observable properties and behaviour. However, we can easily summarise these observed features in terms of symbols where we represent what is happening. Then, we go one step further in using atoms and molecules (and sub-atomic particles) to offer interpretations and explanations. However, the representations inter-relate with the interpretations.
He appreciated a major problem for young learners. What they observe (the properties and behaviour) often gives no direct information that leads naturally to representations or explanations."

"The sciences seek to enable us to make sense of the world around us: understanding how the physical and biological works: patterns, mechanisms, rationale, hopefully to bring benefit to humans. However, the developments arising from the sciences raise all kinds of important questions. All school students will move on to become citizens in societies that are characterised today by complexity. There are important issues that all the societies of the world face today. All our citizens need to be equipped to take informed decisions. Many of these have a strong science basis."

"The central point that Johnstone was making is that understanding is con- trolled by the capacity of working memory. In a subject like chemistry, there are three thought levels: the macro, the sub-micro and the representational. The 'novice' learner cannot handle all three levels at the same time. Therefore, it is essential to work at one level only before considering adding on the other levels. He argued that we start with the macro and that there was a large amount of rigorous meaningful chemistry that encompassed that level only.
The starting point must be to look at the way chemistry curricula are constructed"

"The fundamental issue today is what the chemistry teacher can do when faced with curriculum and assessment structures that are often insensitive to the real needs of young learners. It is here that chemistry teachers need to develop a deep sensitivity for the young learners before them and to be subversive in the way they adapt the curriculum straight-jackets in order to give these learners the best experiences possible."

"What this kind of 'high-stakes' testing has been shown to do is to force teachers to teach to the test, therefore distorting the wider goals for a rich education. Chemistry cannot escape from these insidious pressures. At its worst, highly conscientious teachers have tried to maximise student per- formance by giving all kinds of support. For example, there is now a growth industry in private tutoring, and, in some countries, this has evolved to a major 'industry'. This spoon-feeding has some longer-term effects. There is persistent anecdotal evidence that highly qualified university students are not coping with the more independent learning demanded at that level and are dropping out…
What this kind of 'high-stakes' testing has been shown to do is to force teachers to teach to the test, therefore distorting the wider goals for a rich education. Chemistry cannot escape from these insidious pressures. At its worst, highly conscientious teachers have tried to maximise student performance by giving all kinds of support. For example, there is now a growth industry in private tutoring, and, in some countries, this has evolved to a major 'industry'. This spoon-feeding has some longer-term effects. There is persistent anecdotal evidence that highly qualified university students are not coping with the more independent learning demanded at that level and are dropping out.

"Chemistry, like any other discipline, has its language and terminology. It is often thought that this specialised language causes problems for learners. Early in his career, Johnstone explored the central role of language and found that it was not the technical language of chemistry that was the main source of problems. It was the way chemistry employs ordinary English words, but invests them with specific meanings. These may or may not reflect the meanings used in wider communications."

"The potential in developing and using models (physical or drawn) or diagrams is that they open the door for learners to be able to build mental models which can represent what is thought to happen at the molecular level. Whether models can link the three levels outlined by Johnstone is simply unknown, but it does make some sense. In developing any model or diagram in chemistry, there are two important aspects…It is essential that we really understand the relevant chemistry in order to avoid creating confusions or generating potential misconceptions. Therefore, using target models to show electron sharing or electron transfer may look elegant, but it is so far away from reality that it will utterly mislead. It generates later problems when it is seen not to be correct…
It is also essential that we know our learners. We need to keep right at the forefront of our thinking that their working memory capacities are fixed and limited. Our students are, in varying degrees, 'novice' learners. They come to everything we teach with background ideas that may or may not be helpful. We need to understand what they understand and have some idea how they came to that understanding."

"Of course, the teacher (as an expert) has a task of communicating know- ledge, understanding and experience to the learners (novices). With large numbers, this must involve an element of didactic presentation. However, the real goal relates to understanding and we can define understanding in terms of the ability to apply what we know with a good prospect of success. The didactic approach may be efficient in terms of the transfer of knowledge from 'expert' to 'novice' from a perspective of time and cost. However, we must question if this is meaningful education."

"It all comes back to our aims for school chemistry. Get these right and this determines how we employ laboratory work. While laboratory work is very important for establishing the macro, Johnstone saw laboratory work as a wonderful opportunity to ask questions of the world around and, on the basis of experimental evidence, lead the learners into new insights and understandings. In that sense, laboratory work can be a great bridge between the macro and the other two levels in the Johnstone triangle…
Laboratories are places where students can see how materials behave, albeit in somewhat artificial conditions. They are places where we can ask questions of our remarkable world and see how it reacts when we do things to it. They are places which encourage questioning, critical thinking, dialogue and debate and the development of mental models that seek to rationalise and make sense of the molecular world."

"The goal of all chemistry teaching has to be centred on understanding: enabling the learners to make sense of the world at the molecular world. Simply because that world is inaccessible directly to human senses, there is an inevitable need for representations, often involving the sub-micro, in generating understanding. This immediately places the working memory under pressure as it seeks to cope with chemistry at three levels."

"Many curricula spend time encouraging students to distinguish between physical and chemical changes. This is an utterly pointless exercise. With overcrowded curricula, here is one area which can be ejected easily. Let us return to our salt dissolving in water. Is this a physical or a chemical change? It is relatively easy to reverse. There is no detectable energy change. However, bonds have been broken and new bonds formed but the energy balance gives little discernible energy change overall.
By placing the emphasis on the supposed different criteria for physical and chemical changes, we make it harder for ideas like equilibrium (especially solution equilibria) to make sense later. This illustrates the key principle that, in our attempts to make sense of the world around, we need to be careful not to develop mental models and understandings that need to be untaught at later stages."

"The goal of school education is to equip future generations to develop their full potential, and to be able to be fully participating members of their society. The chemistry curriculum is there to offer a framework to bring maximum benefit to all learners. It is not there to force the learners into the often-artificial logic of a subject discipline as seen by experts in that discipline."

"In his exploration of the areas where students found difficulties; Johnstone was able to demonstrate that the conceptual nature of chemistry now being taught in schools was placing high information demands on young learners. To understand the chemistry, the learners had to hold too many ideas in their working memories at the same time. Overload was the inevitable outcome and understanding became the casualty.
The 'expert' had developed the skills to chunk several key ideas so that the working memory saw them as one, leaving capacity for further thought. The young learner lacked these skills and the working memory could not cope. Faced with examinations, the student was forced to memorise and attitudes to the study of chemistry started to deteriorate."

The Johnstone Triangle: The Key to Understanding Chemistry

Norman Reid, Emeritus Professor, University of Glasgow

Publisher description ('blurb'):

Chapters:

Some selected quotes:

Contents:

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