underneath it is condensation from going through the water, and its
making it bubble and coming out the top.
Teacher: Okay. Right good you’ve described for me certainly what Tve got
here. I’ve got my water boiling here, my steam’s coming up and
hitting my lid at the top
Points water in pan/ raises finger from water to lid / holds finger under Ud
S3: Is it also condensation as when something outside is cold and
something inside is hot and the coldness and the hotness make.
Teacher: Okay. If we look at my diagram where’s the hottest part of my
diagram?
Kate: Points at Bunsen burner
Students: The bottom
Teacher: Well done. Look at where my liquid is dropping down from up on the
lid, is that going to be cooler, the same temperature or hotter than my
Bunsen burner?
Points to area of the screen with liquid/points at the Bunsen burner
Students: Cooler
Teacher: Cooler. Why is it cooler?
Students: ‘Cos its further away from the heat
Teacher: Yeah. Well done.
The teacher continues to construct the experiment as something that he has set up
through his choice of language (“my water”, “my lid”, and so on). The construction
of the problem space, the question of how and why the water gets from the saucepan
to the lid is depicted visually on the screen. Working with the screen the teacher and
student draw attention to the water ‘dropping down’. The teacher clarifies the
phenomenon to be explained, against the backdrop of the continuous display of the
water dripping from the saucepan lid on the screen. The teacher creates the need for
an explanation: the question shifts from ‘what is happening?’ and to the question
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