Transcript Learning processes and parallel conceptions – learning

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?
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Origins
EARLI (feedback much appreciated)
Where does this ( ) come from?
Misconceptions
Alternative conceptions
Conceptual frameworks
HOW?
Manifold conceptions
Multiple representations
How do we learn?
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Evolutionary change
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Revolutionary change – Gestalt shift
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Science learning
Which is the nearest face?
What is needed to learn?
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Learning science requires seeing the
world in a different way
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Requires ability to build up alternative
ways of understanding without
discarding the previous ones
How do we learn?
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Learning is often described as a
construction process, with
knowledge elements being slowly built
into the developing structure
However…
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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?
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There is a need to scale down the size
at which we analyse phenomena
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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…
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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?
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We need to dig beneath specific
conceptions, and to identify more
elementary conceptual resources.
These resources are contextindependent, and relate to patterns
that our cognitive apparatus readily
recognize.
What is the difference?
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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?
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diSessa (1993) proposed such a class
of “hypothetical knowledge structures”
called phenomenological primitives (‘pprims’), 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?
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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
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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
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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
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Matter is continuous and macroscopic properties
are attributed to particles;
Particles are mostly static;
Matter is not conserved in phase changes;
Methodological approach
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Qualitative research project, based on semistructured 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
Data
Categories
Open coding
Axial coding
Data
Intuitive mechanisms
Analyzing the data
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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?
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Characteristics:
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Self-explanatory
Can not be broken down
Descriptions used as explanations
Component gives property
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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 quasiindependent qualities within the substances
which cause the observed properties.
Component gives property
Some examples
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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 property
Some thoughts
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This notion seems to be selfexplicative 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
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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
agent
Some examples
On explaining why food dye dissolves in water
I: 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]
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On explaining why salt dissolves in water
S: It will start to dissolve, if [yes] you stir it
I: If I don’t stir it you don’t think it is going to dissolve?
S: I think some of it will
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Significant change requires active agent
Some thoughts
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Agency is regarded as a crucial attribute in
developing many aspects of cognition.
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Related to causal syntaxes
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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 agent
Gestalt shift?
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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 mechanism
That’s just the way it is!
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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 mechanism
Some examples
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On dissolving food dye in water
I: 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
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On dissolving food dye in water
I think they have reacted together so it’s
now green water, rather than dye and water
Reaction as mechanism
Some examples
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On dissolving salt in water
I: Why is it that the salt dissolves?
S: Because it reacts with the water (…) and when it reacts it
starts to dissolve into it
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On the precipitate reaction (NaCl + AgNO3)
I: Why is it that they might join?
S: Because they react together, because there would be a
reaction
I: What do you mean by reaction?
S: Because you put them together, so they will form a
compound
Reaction as mechanism
Some thoughts
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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
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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 partner
It’s only one’s fault!
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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 partner
Some examples
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On dissolving salt in water
I 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 (…)
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On dissolving salt in water
The 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 partner
Some examples
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On dissolving salt in water
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On dissolving salt in water
When 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 partner
Some thoughts
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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 partner
Gestalt shift?
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Chemical phenomena demand
thinking in terms of interactions
Final considerations
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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
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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
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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:
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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!