Explanatory Power

Filed under: — Bravus @ 1:50 pm

The last couple of posts have focused on explanations in science education, but this one pivots back to explanations in science.

There is a scheme, owed to Hempel, of 5 kinds of explanations in science and their relation to scientific laws, but that is a topic for another day.

In brief, a scientific theory – which is not the same thing as a scientific law – ought to have descriptive, predictive and explanatory power.

There are some laws which do not have explanatory power. Kepler’s Laws describe the motion of the planets accurately, but they are ’empirical’ laws, constructed based on observations. They do not include any explanation of the phenomena they describe and predict. It required gravitational theories from Newton and later Einstein to explain why the planets move as they do.

Indeed, it could be argued that laws – mathematical relationships between quantities – never have explanatory power. They explain what happens, but not why.

Scientific theories, however, explain what happens. That is what a scientific explanation is and is for.

Explanation in Science Education from a Constructivist Perspective

Filed under: — Bravus @ 1:01 pm

When a teacher explains a concept to a student… and, before I continue I should note that the people in those roles may not be in them formally. Parent explaining to child, foreman explaining to new employee, doctor explaining to patient. These ideas are relevant to a very wide range of human activities.

Explanations in science education are different from everyday explanations in a number of features, but that’s probably not something we need to go into in great detail here. We would avoid explanations such as that the contrails of jets are really ‘chemtrails’ of drugs to pacify the populace, not so much because they are not scientific (they aren’t) but because the best available evidence doesn’t support them. It’s an interesting question whether a fallacious ‘explanation’ is an explanation at all, but that might be another post for another time.

OK, digressions aside, I’ll start again: When a teacher explains a concept to a student, that process was historically considered to be what we educational theorists might call ‘transmissive’. The metaphor is like a radio or TV transmission, where the signal that is sent is the same as the signal that is received. The concept is moved intact from the teacher’s mind to that of the student.

There’s a fair bit of evidence, argument and experience to suggest that that’s not … I was about to say ‘what really happens’, but a better way to put it is ‘an effective way to think about it’.

Rather, we tend to have a ‘constructivist’ image of learning 1. In brief, this means that students construct their own knowledge based on their experiences. Those experiences include, but by no means are limited to, the explanations and other experiences offered by their teachers. These in-school experiences are joined with the life experience of the phenomena being discussed: riding bicycles for physics, observing living things – and being living things themselves – for biology and so on.

From a constructivist perspective, then, there is no such thing as the ‘perfect explanation’ of a scientific concept, as a thing unto itself. An explanation is part of the process of explaining (see a post from a couple of days ago on the distinction) that occurs between teacher and student. The explanation provides structured experiences which are the ‘building materials’ from which the student actively constructs understanding.

The importance of the dynamic interaction – and the relationship which forms its context – is that each student is building on different conceptual ‘foundations’. Each has a different set of experiences, and each has made different meanings of them. By listening, drawing on feedback, giving feedback and re-constructing the explanation, the teacher ensures that the explanation offers the best possible materials for that particular student to use in constructing an understanding of the specific scientific concept to be learned.

  1. There are definitely a number of older posts about constructivism on this blog if you’re interested. The Search box on the right side of the page (scroll down a bit) will enable you to find them.


Explaining and Explanation in Science Education

Filed under: — Bravus @ 8:12 am

It was a bit tricky to work out the best order in which to talk about this topic and another one – a constructivist approach to explanation – but I think I promised in the yesterday’s post that I’d talk about ‘explaining and explanation’ next, so let’s do that. But hopefully tomorrow’s post will cast some additional light on this if you’re patient.

Suzie tends to talk about the distinction between nouns and verbs in relationships: having an expectation of our partners, versus expecting something. I kinda see what she’s talking about, in that verbs are inherently more fluid and dynamic than nouns.

The distinction between explanation and explaining is similar, but explaining contains explanation. Let me try to make that a little clearer.

I should also note (this is not one of my more coherent posts in terms of structure!) that this distinction and approach, as well as the constructivist approach, is owed to the German colleagues I recently visited in Bremen, particularly Christoph Kulgemeyer.

In this way of thinking, an ‘explanation’ is a unit in itself. It might be given by speaking or writing, or by speaking in a video or using an animation or simulation, but the explanation is a contained unit of meaning that is designed to increase understanding on the part of someone else, and is somehow delivered.

Explaining is the much larger social and interpersonal, dynamic process within which the explanation is given. It includes the person giving the explanation and the person receiving it. The process of explaining includes feedback, which is crucial. The explanation (as a unit) is modified and re-presented on the basis of the feedback received.

As a teacher (and this includes anyone who understands a concept and is seeking to help someone else develop an understanding of it, not just someone with the formal role) we have to make assumptions about what our student (the person willing to try to develop an understanding of the new concept) already knows, what life experiences they have had, what they are interested in, and so on.

Now, this brings me to one really important distinction between explanations given ‘live’, in classrooms or any situation when human beings are in a room, so that immediate (verbal and non-verbal) feedback is available, versus explanations given in books, videos, games and so on. Kind of by definition, the latter are informed only by the explainer’s ‘best guess’ about the characteristics of the ‘typical’ audience member, and no revision or improvement of the explanation in response to immediate feedback is possible. Simply, this is an explanation largely shorn of the process of explaining.

I’m interested in the implications of this idea for my own research using interactive simulations – although that has all occurred in classrooms with live teachers – and in its implications for things like the ‘flipped classroom’, which rely to a very large extent on explanations given in videos.


Explanation in Science and in Science Education

Filed under: — Bravus @ 12:56 pm

I feel kind of dumb in only really coming to realise this properly now, after working with and writing about explanations for well over a decade, but there is a basic qualitative difference between explanations in science and in science education. They are different kinds of things that have different purposes.

I think perhaps Treagust and Harrison’s interesting work from 1999 and 2000, which was some of the first I read, might have got me off on the wrong track. It talks about the differences between verbal explanations of concepts in, for example, scientific papers versus in science lessons, as well as the differences between these science teaching explanations and ‘everyday explanations’.

They are useful directions, but those three things are all the same kinds of things: verbal explanations, given from one person to another (or a group) with the goal of helping the latter develop a deeper understanding. They all involve, to one extent and in way way or another, teaching.

I’ve been reading David-Hillel Ruben’s ‘Explaining Explanation’ recently, and come to realise that the kinds of explanations he is talking about, when he reviews the work of Plato, Aristotle, Mill and Hempel & Oppenheimer, is not the same thing at all. These ‘explanations’ are the very foundations of science, and are much more like ‘the energy states of the valence shell electrons in sodium metal and chlorine gas explain the reaction between them (given that the activation energy is present)’. In other words, an explanation takes in the various laws or theories of science and explains why something happens as it does.

Now, a particular scientist may well give a verbal or written description of that explanation to another scientist, but that is what Ruben might call ‘an explication of an explanation’: it is not the explanation itself. The explanation is often causal – ‘this happens because this set of antecedent conditions and properties is met’.

Of course, Ruben’s book is academic philosophy, and the water gets very deep very quickly. Do causal explanations have to be determinate and certain or can they be probabilistic? Some explanations in quantum theory, for example, are not deterministic. Are all explanations necessarily causal?

There’s plenty to think about, but just realising that there are these two quite different senses in which ‘explanation’ is used is pretty important if I’m going to write a book on the topic! As it happens, this kind of scientific explanation will be a relatively minor facet of the book, since the focus is on explanation and explaining (and the next post in the series will talk a bit about why that distinction is useful) in science education. I want to know how teachers can create better explanations for the purposes of helping students to come to understand scientific concepts.

Why is this important? Not to boost Australia’s scores on international standardised tests! But because scientific concepts transform our perspective on the world, and empower our students to make positive changes.

Meta: Work In Progress

Filed under: — Bravus @ 12:18 pm

This blog has been moribund for a while, but as I was casting around for a ‘way in’ to write the book I’m writing at the moment, it occurred to me that one way might be to think through things in blog posts. It offers an immediate, if small, audience for the work, and one that I can imagine while writing, but it’s not academic writing so I can be a bit more easy and casual with idioms and images, and with conventions of communication like referencing.

So, over the next few weeks, as the mood strikes and the muse pleases, I’ll kick around a few ideas about ‘Explanation and Explaining in Science and Science Education’ here on the blog. New posts are automatically notified on Twitter and (I think) Facebook: feel free to ignore if this doesn’t interest you.

Looking forward to it: definitely a ‘middle space’ between the ephemerality of Facebook posts and tweets and the permanence of a published book.