teacher, in a lesson with year eight students initially drew an image on the blackboard
(see figure 6.3)j. This image, like typical textbook images, represents the arrangement
of the ‘particles’ in each state, a solid, a liquid, and a gas.
As a result of the modal affordances and constraints of still images, images cannot
readily realise the movement of the ‘particles’: teachers and textbook illustrators who
work with images on the ‘page’ have to resort to the use of arrows and cartoon
symbols to indicate movement. The curriculum focus is on the arrangement and
behaviour of ‘particles’ in discrete and specific ‘states of matter’, rather than on the
process of transformation from one state to another. This focus is easily realised and
brought forth by the spatial and compositional resources of the mode of still image.
In the context of the classroom the teacher can do rhetorical work to animate the
entity ‘particles’ through the dynamic potential of gesture and movement, and in
speech to ‘lexicalize’ (name) movement in particular ways. This serves to bring the
entity ‘particles’ ‘to life’ so to speak: to ‘animate’ them. Earlier work with colleagues
has shown how teachers enact a series of ‘imagined demonstrations’ to bring entities
that are not usually visible into existence (Kress et. al, 2001). The teacher’s shift
between modes in the classroom also represented a shift in the cognitive possibilities
and demands on the learner. In this way the teacher’s action, gesture, image, and
speech interweave rhetorically to convey meaning, to shape students' views of the
world, in complex ways which language alone cannot realise. In the classroom
described above, the main work of the teacher is to give the students the resources
with which they can construct the ‘invisible’, the arrangement and movement of the
‘particles’, to provide the students with a visual scientific overlay for their everyday
view.
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