Learning processes and parallel conceptions. Learning about the particulate nature of matter

Learning processes and parallel conceptions. Learning about the particulate nature of matter

Alejandra García-Franco & Keith S. Taber

Faculty of Education, National Autonomous University of Mexico Faculty of Education, University of Cambridge, UK

Where does this ( ) come from?

Origins EARLI (feedback much appreciated)

Where does this ( ) come from?

Misconceptions

Alternative conceptions

Conceptual frameworks

Manifold conceptions

Multiple representationsHOW?

How do we learn?

Evolutionary change

Revolutionary change – Gestalt shift Science learning

Which is the nearest face?

What is needed to learn?

Learning science requires seeing the world in a different way

Requires ability to build up alternative ways of understanding without discarding the previous ones

How do we learn?

Learning is often described as a construction process, with knowledge elements being slowly built into the developing structure

However…

The process of major conceptual change seems to ask for the building blocks both remaining in place in the existing structure, as they are also used to construct a new edifice.

Learning quanta?

There is a need to scale down the size at which we analyse phenomena

It has been common to see concepts as the ‘atoms’ of conceptual structure, bonded by propositions (conceptions?) into conceptual frameworks

It’s all about size…

Deeper understanding may require us to look into the ‘atomic’ level structure in more detail, at the ‘sub-atomic’ components that may underpin students’ conceptions.

What are we looking for?

We need to dig beneath specific conceptions, and to identify more elementary conceptual resources.

These resources are context-independent, and relate to patterns that our cognitive apparatus readily recognize.

What is the difference?

Conceptions may be technically ‘incorrect’. Resources themselves are not right or

wrong. It should be possible to reconstruct

conceptions by reconfiguring these basic elements.

Technically ‘incorrect’ conceptions may be seen as being inappropriate combinations of fundamental conceptual resources.

What are these resources?

diSessa (1993) proposed such a class of “hypothetical knowledge structures” called phenomenological primitives (‘p-prims’), which could act as “primitive elements of cognitive mechanism - as atomic and isolated a mental structure as one can find”

diSessa, A., A. (1993) Towards an epistemology of physics, Cognition and Instruction, 10 (2&3), pp.105-225

What are these resources?

These hypothetical ‘atoms’ of cognition are primitive in the sense of acting at an early stage of cognition, and identifying phenomena as matching common general patterns.

P-prims so far Several researchers (e.g. diSessa, 1993, Hammer,

2004) have identified p-prims that can explain a good deal of students’ reasoning in the physics domain.

There has not yet been substantial use of these ideas in the context of learning chemistry. only now are chemistry educators considering whether this idea is useful in making sense of student thinking and learning in chemistry (Taber & Tan, 2006).

Chemistry has the special characteristic of being largely explained in term of entities conjectured at a different scale

Hammer, D. (2004) The variability of student reasoning, Lecture 3: Manifold cognitive resources, Proceedings of the Enrico Fermi Summer School in Physics, Course CLVI, Italian Physical Society. Available at http://www.physics.umd.edu/perg/papers/papers-ee.htm

The topic

The particulate nature of matter is part of the staple science curriculum diet of secondary students throughout the world.

It is widely acknowledged as being fundamental to understanding different concepts in school chemistry, as well as a powerful theory that can illuminate different aspects of the nature of science.

Common misconceptions in this topic

Relate to: Interpreting the microscopic world in

macroscopic terms Difficulty of interpreting observable

phenomena in terms of interactions between atoms and molecules Matter is continuous and macroscopic properties

are attributed to particles; Particles are mostly static; Matter is not conserved in phase changes;

Methodological approach

Qualitative research project, based on semi-structured interviews with secondary students in English and Mexican secondary schools (12 – 17 years).

Grounded theory approach for the analysis Iterative cycles of revisiting data whilst

developing theoretical sensitivity.

Analytical approach

DataOpen coding

Axial codingData

Categories Intuitive mechanisms

Analyzing the data

Explanations can be seen as composed of a range of candidates for p-prims.

Some of these p-prims are related to previous findings (literature), some others seem to be specifically related to chemical phenomena.

And, how do we know when we see one?

Characteristics: Self-explanatory Can not be broken down Descriptions used as explanations

Component gives property

There is a component in the substance responsible for its properties.

Properties can not be explained using more fundamental entities such as particles and interactions between them.

Could imply the idea that there are quasi-independent qualities within the substances which cause the observed properties.

Component gives property Some examples

On dissolving regular salt in water(…) don’t know (…) the salt makes it cloudy, perhaps [there is] a chemical in the salt that makes it cloudy

On precipitate reaction (NaCl + AgNO3)is a lot slower and I think it’s the silver in there or one of the parts from the silver nitrate that is in there has made it all milky because it is a cloudier substance

Component gives propertySome thoughts

This notion seems to be self-explicative and may stand in place of interpreting properties.

From this component gives properties perspective, properties seem to be given to substances according to their composition and that composition can not be explained any further.

Significant change requires active agent

There needs to be an actuating agent (commonly heating or stirring) in order to explain observed changes.

Changes are not explained in terms of intrinsic properties of the system (movement).

Significant change requires active agentSome examples

On explaining why food dye dissolves in waterI: Why a convection current?S: I don’t know, because the water might be warmer at the top, I think

(…), no at the bottom, and then if it’s more dense, then it would go up to the top and then as it gets colder at the top, then it would become less dense and then go to the bottom again

I: ok, so why should it be more warm at the bottom than at the top? We are not heating it up or anything

S: (…) the paper might be warmer [the beaker was on a paper sheet]

On explaining why salt dissolves in waterS: It will start to dissolve, if [yes] you stir itI: If I don’t stir it you don’t think it is going to dissolve?S: I think some of it will

Significant change requires active agentSome thoughts

Agency is regarded as a crucial attribute in developing many aspects of cognition.

Related to causal syntaxes

Agent Patient

Movement (or change) is always seen as an effect; therefore to explain change it is necessary to identify a cause.

Systems tend to have a static predisposition

Significant change requires active agentGestalt shift?

When explaining phenomena in terms of particles it is necessary to conceive a system in which particles have intrinsic movement (no identifiable agent).

There needs to be a significant change in considering that systems have a ‘static predisposition’ and therefore it is possible to explain changes without identifiable agent.

Reaction as mechanismThat’s just the way it is!

Familiar phenomena do not need to be explained.

Students assert that something happens because that is the way it is meant to be or supposed to happen.

Property or behaviour of a given substance is just an inherent ‘natural’ quality to be expected in that context.

Reaction as mechanismSome examples

On dissolving food dye in waterI: What do you mean by dissolving, when you say dissolving, what is it?S: Well, the water has reacted with it and turned it into a different colour liquid

On dissolving food dye in waterI think they have reacted together so it’s now green water, rather than dye and water

Reaction as mechanismSome examples

On dissolving salt in waterI: Why is it that the salt dissolves?S: Because it reacts with the water (…) and when it reacts it starts to dissolve into it

On the precipitate reaction (NaCl + AgNO3)I: Why is it that they might join?S: Because they react together, because there would be a reactionI: What do you mean by reaction?S: Because you put them together, so they will form a compound

Reaction as mechanismSome thoughts

Watts and Taber (1996) have used the term ‘explanatory gestalt of essence’ to refer to those reasons that students give to phenomena they feel there is no need to explain.

This p-prim could be related to what diSessa calls principle of obviousness. There is no sense (from the student’s point of view) in trying to explain what happens when two substances are mixed.

Watts, M. and Taber, K. S (1996) An explanatory gestalt of essence: students' conceptions of the 'natural' in physical phenomena, International Journal of Science Education, 18 (8), pp.939-954

Reaction as mechanism Some thoughts

This could be related to familiarity with common phenomena from a young age, probably reinforced by the way such ideas are described in usual ‘life-world’ dialogue.

Science education might be seen to be partly about getting learners to start to question that which had seemed so familiar as to be beyond question.

One active partnerIt’s only one’s fault!

Some students suggest that when substances interact it is only one of the substances which is held responsible for the changes.

It is the substance that is perceived as “strongest” the one that is the active part whereas the other substance involved has a rather passive role.

One active partnerSome examples

On dissolving salt in waterI just imagine the water would erode it in a way (…) rubs against the salt, (…) something in the salt reacts with the water, so (…) it kind of makes it smaller and smaller either by compressing the salt in some kind of way or like just making each grain of salt gradually just fade away into little particles and makes it like little particles come apart and eventually each grain of salt must have lots of little particles, it just splits in half and then again, and then again until they become (…)

On dissolving salt in waterThe water washes away all the particles from the salt and ends up into like single particles, surrounded by water and then it is not visible anymore

One active partnerSome examples

On dissolving salt in water

On dissolving salt in waterWhen it hits the water, kind of makes the material melt (…), but when the solid goes back to a liquid, the water kind of erodes it and washes it.

One active partnerSome thoughts This could be related to Andersson’s (1986)

experiential gestalt of causation where the way to explain changes is by identifying one active agent, one patient and one instrument.

There is a physical “feeling”, when students are trying to imagine phenomena in the microscopic level using references to common events.

Animistic and antropomorphic explanations.

Andersson, B. (1986) The experiential gestalt of causation: a common core to pupils’ preconceptions in science, European Journal of Science Education, 8 (2), pp. 155– 171.

One active partnerGestalt shift?

Chemical phenomena demand thinking in terms of interactions

Final considerations

It seems to be that the categories derived from the point of view of ‘conceptual resources’, with emphasis on p-prims can be useful to describe students’ explanations of phenomena related to the particulate nature of matter.

We could find some mechanisms that seem to be fundamental units of knowledge (atoms or quanta) that make up the explanations students construct in different cases.

Final considerations

Useful application of p-prims in everyday life, provides a ready set of conceptual resources for interpreting the abstract and inaccessible world of molecules, ions, electrons and atoms used to model and explain chemical phenomena.

Final considerations

There is much scope for revisiting the extensive misconceptions literature in chemistry, in the light of the ‘p-prims’ perspective.

Remains to be seen how the idea of p-prims could helps us to: Explore development in student thinking to see how these

units or p-prims evolve. Offers advice to teachers on how to better direct learners

to use their conceptual resources to build up explanations of basic chemical and physical phenomena which better match the curriculum models being presented in class.

Move beyond description into the consideration of the dynamics of knowledge construction

Finally…

THANKS FOR COMING!