Going round and round in circles

Going round and round in circles: Scaffolding learning in science

One of my publications is:

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A recording of the talk

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Abstract

The idea that teachers 'scaffold' student learning is a common feature of educational discourse, and many kinds of learning resources are described as 'scaffolds'. However, the term is often used very loosely, as if any learning resource inherently acts as a scaffold, without being linked to its original theoretical basis. In this keynote talk I will discuss scaffolding in the context of the learning theory of Vygotsky (from which it derived) and the wider constructivist perspective on learning and teaching. I will consider what the criteria for a genuine 'scaffold' might be and why designing such scaffolds can be highly challenging.

I will illustrate this with the example of a small scale study of an attempt to devise and test a learning resource that would act as a scaffold in relation to a specific physics concept where many students have alternative conceptions that act as barriers to learning canonical physics.The resource actually involved a combination of two types of scaffolding tools – the first (a scaffolding 'PlaNK') intended to help learners bring to mind relevant prior learning, and the second (scaffolding 'POLES') to help them construct new knowledge.

In overall terms, it seemed the resource had only modest effect. A closer look at the data suggests the resource substantially supported some learners, yet did not seem to help many of their classmates at all. Whilst this might seem disappointing, it is perhaps precisely what the learning theory underpinning scaffolding would have predicted.This highlights how the development of effective learning scaffolds needs to be both iterative, a cyclic development process, and differentiated. It also reflects the central role of the classroom teacher in the effective use of scaffolds.

My aims in this talk are to explain why it is difficult to produce classroom resources and activities that genuinely act as scaffolding, but also why it is important to persevere with attempts to scaffolding student learning, both as individual teachers, and as an educational community.

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The text of the talk

The zone of proximal development is a subtle notion, and it needs to be probed and tested gently, and over time.

Going round and round in circles: Scaffolding learning in science

Thank you for inviting me to talk to you today.

In this talk I am going to explore the idea of 'scaffolding'.

Scaffolding

The notion of teachers scaffolding learning is very common in educational discourse, but the term is often used very loosely in a way unconnected with the theoretical background within which the idea was developed. In this keynote I hope to briefly introduce the idea of scaffolding in relation to the learning theory of Vygotsky that originally motivated it, and consider the challenge for teachers in authentic scaffolding of student learning.

Effective scaffolding of student learning is challenging to achieve. As an illustration I will discuss one small scale attempt to apply the notion of scaffolding to a specific learning difficulty in senior school physics. So, my starting point is the observation that discourse about teaching often refers to 'scaffolding learning' or providing students with 'scaffolds' for their learning. However, often the term 'scaffold' seems to be used as if it is just another word for 'support'. Any structure offered by teachers is treated as a scaffold. Taken to the extreme, an instruction such as

'please read chapter 4 of the textbook before the next class'

could be seen as a scaffold in that sense. However, this devalues the point of having the specific term.

Scaffolding is an idea which derives from the learning theory of the Russian polymath, Lev Vygotsky, and his ideas about learning and development, and what he termed the 'Z.P.D', or zone of proximal development.

Vygotsky's ideas fit within the broader frame of a constructivist perspective on learning. So, it is useful to start by quickly looking at the key points of educational constructivism.

Constructivism

I refer here to educational constructivism, sometimes referred to as pedagogical or psychological constructivism, as there are somewhat related but distinct notions of constructivism in other fields such as the epistemology of science and in social research methodology, but today I am only talking about the notion of constructivism as far as it relates to the teaching and learning of academic disciplines such as the sciences.

Constructivism can be seen as reflecting the commonplace observation that learning of abstract technical ideas is challenging. Generally, a teacher cannot simply offer a clear and correct account of any extensive detailed abstract material that is unfamiliar to students, and expect the learners to immediately acquire an accurate and full understanding of the material.

Of course, constructivism goes beyond this simple observation to consider how human learning occurs and, so, how teachers can best teach in the light of the cognitive constraints on learning. It is worth pointing out that whilst such constraints prevent most of us picking up an advanced book in some unfamiliar discipline and developing immediate expertise on a topic by simply reading through in an afternoon: we can also see this cognitive apparatus as being responsible for allowing us to acquire and share complex abstract ideas, and so to have enabled us to develop and progress the sciences.

To borrow a common idiom, a glass that is half-empty is also half-full.

There are also good reasons to think that the conservative nature of human cognition, that is the bias towards current over novel ways of thinking, probably has an evolutionary basis. That is, highly labile thinking might enable revolutionary thinking, but in doing so could undermine the conditions for our survival in a largely stable environment.

Constructivist teaching

So, if we think about teaching, the broad aim is usually to move on student thinking, in terms of levels of knowledge and understanding, towards specified targets set out in a curriculum. The starting point for this change is determined by the actual pre-existing levels of knowledge and understanding of the learners. The gap between where students are originally at, and where they are intended to get, is sometimes called the learning demand. Teaching can be understood as action designed to help bring about such desired learning.

Constructivist approaches are informed by research into the nature of student thinking and learning, to best work with what we know of how human cognition works. So, one starting point is that what is specified as target knowledge is often abstract, and may be counter-intuitive. This tends to become more obviously the case as we progress to higher levels of the education system. By definition, a suitable student for a course of study does not already have knowledge and understanding that matches the target knowledge. In advanced courses, however, it is assumed the student is not starting from scratch.

Usually, for any specific course, there will expectations about the prior learning of students. In particular, there is often prerequisite knowledge which is needed to make good sense of the course material. Yet, in reality, students often have incomplete prior knowledge. Moreover, even when students have acquired the logically necessary pre-requisite learning to make sense of a course, they will not always bring it to mind at the pertinent time.

So:

• The teacher cannot assume students understand what they are already expected to understand.
• The teacher cannot assume that students will appreciate the relevance of foundational knowledge that the teacher is implicitly relying on in developing a topic.

Not only this, but certainly in science subjects (and probably other academic areas), students often already have established prior knowledge of a topic that unfortunately does not match the canonical account. Students can think they understand a topic when they do not share the accepted understanding the teacher is relying on. That is, they hold alternative conceptions or misconceptions. Sometimes students' ideas are completely contrary to the accepted canonical idea. I will refer to an example of this later in the talk.

In science subjects, we also have the complication of the centrality of models. Much scientific knowledge is of the form of models and representations and theories that are not understood to be absolute reflections of nature, but rather as tentative, accounts, or as approximations, or as useful simplifications. Moreover, the curriculum models and teaching models used at various stages of the education system further simplify the canonical accounts that are often themselves models.

Yet students often lack a sophisticated appreciation of the nature and limitations of these accounts, so struggle when what they have previously been taught – say Newtonian mechanics, or a model of the atom with shells of electrons – seems inconsistent with what they are taught in more advanced classes.

One of the key constraints on human learning is working memory.

Much informal human learning in everyday life occurs without requiring reflection and conscious focus on the activity. Unfortunately this does not apply to formal conceptual knowledge represented in symbolic form. That is, you can learn to ride a bicycle by repeated attempts to ride a bicycle relying on feedback processes that operate at a preconscious level, but no one learned about the periodic table or Newton's law of cooling in this way. Learning a science subject, or indeed any material represented in a symbolic system such as verbal language, requires actively processing information in working memory.

The knowledge of an expert in a field is well established, and highly integrated, and large conceptual frameworks can be accessed into working momentary as single chunks. However, working memory is severely limited in how much NOVEL material it can admit at once. The general rule is that we can relate a little bit of new information to the most extensive complex prior learning once it has been fully consolidated: but more than a few elements of unfamiliar material soon lead to overload.

We very soon fail to cope if we do not break the new information down into small manageable quanta and limit ourselves to thinking about just a few of these at any one time. So, in teaching, this requires working with small learning quanta, and sequencing them to deal with a few at a time.

However, I also referred to consolidation. Novel material, even when understood, is unlikely to be retained, and then to immediately become robust enough to itself be used to help understand further novel material. Unless novel learning is strongly reinforced in the days and weeks after first met, it is unlikely to be readily recalled later.

The ideal student undertakes this reinforcement through an extensive and well-planned regime of

• frequent review of their learning,
• repeatedly revisiting their past notes, and
• reworking them in the light of further study.

Anyone teaching students who are not this perfect [sic, consider ideal student cf. ideal gas] needs to build regular reinforcement into the teaching itself.

Moreover, it takes time for the brain to take new learning and start to fully integrate it into existing knowledge structures such that it becomes automatically associated with, and retrieved as part of, substantive frameworks of knowledge. As making sense requires proceeding through modest leaning quanta, learning is incremental, occurring bit by bit.

The key feature of the constructivist perspective on learning is how new learning relies upon the learner making sense of new information in terms of current knowledge and understanding. Each learner can be considered to bring to class a unique repertoire of knowledge, experiences, vocabulary, and so forth, that can potentially be used to interpret teaching.

• As making sense requires interpretation in terms of existing ways of understanding, learning of meaningful material is always interpretive. As making sense requires proceeding through modest learning quanta; learning is incremental.
• As making sense requires interpretation in terms of existing ways of understanding; learning is interpretive.
• As learning is both incremental and interpretive; it tends to be iterative.

That is, once habits of thinking are formed, they tend to channel future thinking. When students have alternative conceptions (misconceptions) they are likely to make sense of teaching in terms of those alternative conceptions. New learning may distort the [teacher's] intended meaning to be consistent with existing alternative understandings. This is not inevitable, but it is common unless the teacher teaches in ways that take students' current ideas into account. So, one foundation of constructivist teaching is diagnostic assessment.

The teacher needs to start by checking that the expected prerequisite knowledge is available, and sufficiently matches the canonical account. If not, some remedial input is indicated. The constructivist teacher does not just offer an extensive serial presentation of the course material, but finds activities that support learners' engagement with course material in productive ways.

That is, rather than just watching, listening, reading; students ask and answer questions, undertake practical activities, join in group discussions, tackle exercises and problems, plan enquiries, draw concept maps, and so forth. These activities are designed to help build from the learner's current understanding towards target knowledge, but this may need to be a staged process as the difference between where they are, and where they need to be, the 'learning demand', may only be breached via stepping stones of intermediate activities.

This is reflected in the notion of the 'learning progressions' that have been the focus of much recent research.The constructivist teacher structures the learning experience so that at each stage the learner only has to process manageable learning quanta.

The constructivist teacher finds ways to make the unfamiliar familiar, by making abstract ideas concrete, and by showing how the material being taught has links with what is already familiar to the learner. So, this is a general scheme for what constructivist teaching is about. Scaffolding is a strategy used within this perspective.

Vygotsky

Lev Vygotsky was a Russian psychologist with wide interests, who worked in child development among other areas. Vygotsky looked at development as processes at different scales – from human evolution to the way a concept develops for an individual learner.

Vygotsky was a contemporary of Piaget who put particular emphasis on social processes in learning and development. His thinking was influenced by the Soviet system in which he worked, so he saw development as a dialectical process. Vygotsky considered the role of symbol systems, such as language, in learning and teaching, and not only differentiated between spontaneous and academic learning, but also considered how they interacted during conceptual development.

Vygotksy died tragically young, of tuberculosis, at the age of 37. (This was not exceptional at that time. At its most prevalent, TB killed something like 1% of the population each year.) However, by the time of his death Vygotsky had fallen out of favour in the toxic Soviet context where it was very common for scholars to be accused of ideological faults and loose their academic positions – if not their freedom or indeed life. It is said that at one time scholars wishing to read Vygotsky's work had to get a special library permit from the K.G.B., the Soviet Secret police.

Vygotsky's work is well known today, due to its being championed by others, including his colleague Alexander Luria who survived the Soviet purges and went on to become a world famous psychologist. However, perhaps the most important champion was the US psychologist Jerome Bruner who praised Vygotsky's work and help devise the idea of scaffolding based on it.

Scaffolding: an analogy

The analogy is with the idea of chemical change. Many chemical reactions do not proceed spontaneously at any significant rate at normal conditions where there is a high activation energy. In metabolism, however, many reactions occur at controlled rates, under conditions of, for example, temperature, when there would be no significant reaction in vitro. This is because metabolic reactions are often facilitated by very effective catalysts, enzymes.

The enzyme is able to lower the effective activation energy making a reaction much more viable. Metabolic reactions often occur via a number of discrete steps – so, for example, in respiration there is a net reaction of glucose with oxygen to form carbon dioxide and water, but this occurs in carefully controlled stages. The process is structured into discrete steps. We have seen that discrete steps may also be very important in making learning manageable.

Enzymes also reduce the degrees of freedom of a reaction. Because enzymes bind to their substrates and combine with them in very specific ways, a molecule which could, when free, follow a wide range of possible change pathways is constrained to the path which is productive in relation to the catalysed reaction.

I am then suggesting that scaffolding in teaching is in some ways analogous to enzymatic catalysis of a metabolic reaction.

The zone of proximal development

To understand how scaffolding works, it is important to understand one of Vygotsky's original ideas, which is known as the Z.P.D. This stands for the zone of proximal development, or it is sometimes known as the zone of next development.

This is one of three zones in what we might think of as a kind of phase space. This phase space however has dimensions related to the various competencies a person may have. Clearly this is highly multidimensional: it needs to represent one's ability

• to play the piano,
• to integrate complex functions,
• to use a Bunsen burner,
• to read social situations,
• to play badminton,
• to recall atomic masses,
• to use biological keys,
• and so on, and so forth.

Here it is represented in two nominal dimensions partially because that makes it easier for you to understand, but mainly because it makes it much easier for me to draw.

Indeed, I am simply using the x-direction to represent some hypothetical competence of interest to us – perhaps to understand and explain orbital motion in terms of Newtonian physics, for example. The important point is that this phase space is divided to a first approximation into three zones.

• The first zone represents the current competence of the learner. This is the zone of actual development.
• The third zone represents abilities and skills well beyond current competence – the zone of distal or far development.

Vygotsky realised that the most interesting zone was the intermediate one, which represented those things the learner could not yet do for themselves, but which could be understood as next steps that could build upon current competencies. This is the much referenced zone of proximal, or next, development. Vygotsky suggested that knowing about a student's Z.P.D. was more useful for a teacher than knowing about her Z.A.D., and that educational assessment should focus on what the learner was ready to move onto.

The critical feature of the Z.P.D. is that a learner can achieve in this zone in a meaningful way, but only with some level of support. Here I have just represented our one hypothetical dimension of interest. The learner needs no support to work in the Z.A.D. Here she already has competence. With practice here she can achieve mastery of tasks in terms of speed and accuracy – but cannot develop beyond current capacities to anything substantially new. If our learner was paired with another who had not yet achieved competence at her level, then she may be able to support that learner in their development.

In the Z.P.D. our learner has potential to be moved on herself. But this depends on the right kind of structured support being available from someone who has already acquired competency here. That is, someone who would be working in their Z.A.D. – which might be a teacher or simply a peer who had made more headway. In the Vygotskian model, the learners works alongside someone more competent, and achieves vicariously, but over time comes to internalise the supported activity till it becomes 'owned' and external support is no longer needed.

Although the prototype is direct interaction within an immediate social context, Vygotsky also explored how people develop symbolic representations that can act as tools – tools such as natural language and number systems that support cultural sharing and so intellectual development. We can interact indirectly, and these days very much virtually and digitally – which is why learner development did not need to come to a complete stop during the recent global pandemic.

Science is especially rich in these symbolic tools: chemical formulae, field lines, Lewis structures, Feynman diagrams, and all the rest. However, whatever the medium, such representations can only be understood when the learners have the necessary interpretive resources to make good sense of them.

Locating learning activity in the Z.P.D.

We can relate the Z.P.D. to a model such as this.

• Teaching needs to match the demands of a task to the skill level of the student. Work that offers no challenge offers no opportunity for development.
• But, then again, tasks that offer too much challenge provide no potential for success, and so, also, no opportunity for development.

This might suggest teachers cannot win: we either set work the student can do, but which cannot benefit them, or work they cannot do, which also cannot benefit them. But this misses an important feature of the teaching situation.
That is, the support offered to help move the learner beyond what they can already achieve unaided.

The teacher's task is to set work which is sufficiently challenging to move students on in their development, but also to provide the scaffolding which will enable them to successfully engage whilst the task is still beyond their competence. In a sense, we are referring to the so called learning paradox as discussed in Ancient Greece.

Surely, it is suggested, if something is genuinely unknown to us, we have no way to seek it out. Therefore, if we think we have learnt something new, we must have already known it at some level. Thus if Socrates could, through Socratic dialogue, elicit a geometrical proof from an uneducated slave boy, then that knowledge must have been innate. Plato explained this in terms of an eternal soul that has ultimate knowledge which it seems to forget during our lives.

The constructivist model suggests that we are capable of coming to new knowledge as our cognitive systems are capable of building up new constructions, new models, to make sense of experience. Coming to understand is the construction of new models that can help us predict what will happen in our environments – models that will be retained and relied upon if they seem to work.

However, we only build in small steps, and using the constructions materials available: the repertoire of existing ideas and interpretations of past experiences we have accumulated.

If we build a model of the world that has the sun carried across the sky each day by an angel, and that model allow us to effectively predict the future, we may well be happy enough with that understanding unless and until we have reasons to question it.

Left to our own devices we would all be able to come up with new ideas, and some of these will have some value. However, as a a community, we can share experience, and in particular help new thinkers think along lines that have proved productive in the past. So, we do not need to slowly work through all the thoughts of Newton and Galileo and Curie and Einstein and all the rest as they have already done that for us, and we have symbolic tools to represent and share the outcomes of their most productive ideas.

If some idea is within our Z.P.D., and we can be supported to assimilate it, then our Z.P.D. will have expanded to a point where something else may now be within reach.

Learning about the Newtonian world-view

The example I am going to talk about today is related to one of the most well recognised areas where people commonly have alternative conceptions. A common sense ontology makes the very important distinction between moving objects and stationary ones. Certainly 'very important' in evolutionary terms. If a food source, or a predator, or a potential mate, or an enemy's spear, is moving this can be highly significant. So, we tend to notice motion.

Yet physics tells us that there is a more significant distinction. Perhaps not more significant to the person at subsistence level seeking food and trying to avoid being eaten, but more significant for those of us with luxury to reflect upon and try to understand the universe.

This is the distinction between accelerated motion and uniform motion – the latter including being stationary which is of course just a uniform motion of zero m/s. This is because, at least in the ideal world of physics where we strip away complications, objects remain in their current state of motion, unless acted upon by a new force. Strangely [sic] this is counter-intuitive to most people who falsely [sic] believe that moving objects tend to soon come to a stop unless you keep pushing or pulling them. This is perhaps the most common alternative conception in all of science, albeit one that has a strange match to experience most of the time!

Orbital (as an example of circular) motion

In particular, I am going to look at the example of orbital motion. Physics tells us that the constant change of direction, and, so, of velocity, must be due to an unbalanced force acting – a centripetal force. The satellite is not in uniform motion as it is constantly acceleration as it changes its direction of travel. Yet, it is very common for students to suggest that circular motion is an example of a kind of equilibrium where the force acting on the satellite must be balanced,

Even students who have acquired the Newton notion of inertia when discussing rectilinear motion, often fail to transfer this effectively to the case of circular motion. Indeed, I even noticed these statements in a book by a science professor who was seeking to explain the principles to readers. The thing about alternative conceptions is, of course, that they do not seem alternative to the person holding them! I imagine we all have some, even if we are science teachers.

I am going to discuss a very simple tool, or strictly a pair of tools, that was designed to help physics students understand the Newtonian model as applied to circular motion. These were students studying at what is called 'Advanced' level in English schools – usually 16-18 year old students who had done well in school science and were taking an elective physics course. The assumption was that these students should have learnt the basic Newtonian principles but had not yet considered curricular motion from that perspective.

Scaffolding tools

I am going to distinguish two types of scaffolding tools that I refer to as scaffolding planks and scaffolding poles. The planks are basically making sure the foundations are firm and level, and the poles building on those foundations. In any new learning we rely on the learners' prior learning. We not only require that the student has the right prerequisite learning, but also that that the learner will activate if from among their vast resource of prior learning and compile it correctly to make good use of it.

As David Ausubel pointed out, for learning to be meaningful it is not enough there is a potential connection with prior learning, but that the connection is made. Most of a learner's prior learning and experience is of no direct relevance to a new learning task.

It is usually pretty obvious to a teacher which prior learning is relevant in a particular learning context. But that is because they are both experts in the subject matter, and their professional role involves them thinking about how to teach the subject. Unless the teacher is explicit about this, what is obvious to the teacher may be far from obvious to the student. So, part of the role of a scaffolding plank is to help the learner identify the relevant prerequisite learning for a new learning task and to bring it together to draw upon as needed. Then the scaffolding poles can help the student build upon this foundation

This is the plank. It is a very simple review of basic ideas that students should already know before thinking about orbital motion. It is set out as a matching task: a student who has learnt the basic principles should be able to match up the divided statements. You may want a moment to just work this through.

The second tool [the scaffolding pole] was a simple diagram which asks students to form a chain between some key concepts terms using the connector of 'implies' or 'must mean that'.

For example,

• does an unbalanced force imply a change in direction?
• Does a change in direction imply a curved path?
• Does a change in velocity imply an unbalanced force?

The pole task draws upon the basic ideas that students should already know, and which should have been brought to mind when they just completed the previous plank task. So, a solution would be that

• an orbit implies a curved path;
• which implies a change of direction;
• which implies a change in velocity;
• which implies an acceleration;
• which implies the application of an unbalanced force.

Other chains might be argued for, but it is not the response that matters, rather the thinking through, using the foundational principles. The task is meant to scaffold the thinking about why basic Newtonian principles imply an unbalanced centripetal force operate in orbital motion. So, these two tasks used together were designed to help scaffold learners who had mastered basic Newtonian principles apply these to the recognised as problematic topic of orbital motion.

The assumption was that the basic ideas were part of the Z.A.D., as checked by the PLANK matching activity, and if so, an understanding of orbital motion might be within reach in the Z.P.D. as long as suitable structured support was provided. Certainly, for a learner where the basic ideas were well-established and had been consolidated sufficiently to be robust knowledge, we might anticipate that an understanding of circular motion in Newtonian terms would be within the Z.P.D., and that once this has been constructed it could with suitable reinforcement come to be considered within an expanded Z.A.D.

Evaluating the scaffold

But does this tool work?

To test this students were asked, after they have completed the scaffolding activity, to explain why planets move in nearly circular orbits around the sun. To see if the activity had actually supported possible change, they were also asked the same question BEFORE completing the activity. If their answers after the activity were judged better than those given before, we might put this down to the effect of the activity on their thinking.

However, an improvement could be down to other factors. [Maturation is unlikely to be a factor here given that they would complete the sequence of activities on the same occasion, so will not have had time to mature to any substantive extent.] Answering the question the first time could act as a learning activity, such that even when giving a poor answer at the first attempt a learner may sufficiently engage with the question to support a better answer later.

We know that the brain often works on problems preconsciously, such that something that we are struggling with suddenly becomes clearer later. It does not seem likely that the time lag would be sufficient to facilitate new insight, but without some kind of control we have to admit it is possible that replacing the activity with a five minute break between the two attempts to answer the question might have also led to an improvement in response. For this reason a comparison group was used.

Both groups completed a sequence of four activities.

• The scaffolding plank activity.
• A first attempt at the question about orbital motion.
• A simple sequencing question.
• A second attempt at the question about orbital motion.

So, the only difference between the two conditions was that the activity carried out between answering the same concept question twice was in one case designed to structure thinking about the physics principles related to the concept question.

Ideally, one would test this by randomly selecting a large number of students from the population of interest, here, A level physics students, and randomly assigning them to one of the two conditions. In practice such ideal procedures are seldom possible in small-scale, unfunded projects. Instead, we relied on some teachers to volunteer to administer the materials in their classes.

Randomisation to conditions means that each person in a sample is equally likely to be assigned to either condition. Whilst, strictly, random selection may never be possible, there are plenty of approaches that do a good enough job- (such as writing names on slips of paper, putting then in a box, giving it a good shake, and then removing the slips blind). Here the researchers did not know the names of the participants, as these were only known to the teachers. It also seemed unreasonable to expect the volunteering teachers to undertake a randomisation process with the students in their classes. Instead they were asked to simply give out the materials to each student in their class in turn – with the two versions of the materials having been alternated in the pack.

Was prerequisite learning in place?

Whilst the plank activity was part of the scaffolding process, it also acted as a kind of filter to ensure that the advanced physics students using the scaffolding pole activity did have the basic concepts needed for success. In practice, it was found they quite a few failed to successfully match all the sentences.

About a quarter of those in the comparison condition, and about a third of those in the scaffolding condition failed on the initial task. This reminds us that teachers can never assume even the most basic foundational prerequisite knowledge is automatically available to students just because they have met course requirements.

Did the scaffold make a difference?

The responses to the concept question were rated on a seven point scale by an experienced researcher* who had taught physics at this level. A higher proportion of students increased their score at the second attempt in the scaffolding condition than in the comparison condition. The differences were not tested statistically, as the conditions for a true experiment (random sampling and assignment) were not met.

None-the-less, in this sample, there did seem to be a modest effect from completing the scaffolding pole activity. Indeed, in the comparison condition, student mean scores deteriorated between the first and second attempt at the question. This was a small change, and presumably reflects how some of the volunteered students who had nothing at stake from the activity, felt that having answered a question once, they were not going to put as much effort into doing exactly the same thing again a few minutes later.

In absolute terms, the effect in the scaffolding condition looks impressive – a more than doubling of student scores. However, this was from a very low base.

The main finding was that even those students who could successfully complete the PLANK activity, struggled to apply these ideas to circular motion. On average the scaffolding poles activity seemed to help shift student performance from extremely poor to only very poor!

The comparison condition showed relatively little change between the two attempts. The scaffolding condition did suggests something interesting. Although the average performance did not change vastly this seemed to reflect how some students made relatively large gains, whilst others got no benefit, or at least no immediate benefit, from the poles activity at all. Perhaps these results should not surprise us.

Discussion of findings

Research shows that these basic physics ideas are counter-intuitive, and student alternative conceptions in this areas can be very resistant to change.
Moreover, the activity was not an authentic reflection of normal teaching, where a teacher interacts with a class, and so builds up an explanation working from where the learners are, and pacing and adjusting teaching according to student repossess. Paper tools, such as used in this study, will never offer the interactivity of a skilled human teacher. The Z.P.D. is a subtle notion, and it needs to be probed and tested gently, and over time. Sensibly, the tools used here would not simply be given to learners instead of teacher input, but as component tactics within an overall teaching strategy.

In effective classroom teaching teachers use sequences of activities, organised in different ways. So, tools such as this can be incorporated into such schemes.

Conclusion

It is important to appreciate the serious limitations of this small study.

However, I would strongly argue that more research is indicated into how we can match learning resources and activities to students' current readiness to learn, their Z.P.D.s, and so ensure these inputs do scaffold development. I think this very modest study does offer some evidence that scaffolding really can support learning, albeit that scaffolds need to be well-matched to the individual learners.

* Thanks to Dr Richard Brock for analysis of the responses.

The study discussed here is:

Taber, K. S., & Brock, R. (2018). A study to explore the potential of designing teaching activities to scaffold learning: understanding circular motion. In M. Abend (Ed.), Effective Teaching and Learning: Perspectives, strategies and implementation (pp. 45-85). New York: Nova Science Publishers.

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