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TGC1: The gas state
Notes on the animation.

Students find gases mysterious, and have no real sense of what a ‘gas’ might be. The intention here is to introduce
the possibility of a gas state, in which the particles have sufficient energy to overcome the hold which has been
keeping them all close together, as an extension of the particle theory ideas which students have already
encountered. You could introduce this animation as part of a ‘thought’ experiment’, asking students to speculate
before showing the animation and introducing the idea of ‘the gas state’. This then raises the question of what a
substance would be like in the gas state – what would we observe – and leads on to the experiment shown in the
next video.

You can find out more about research into students’ understanding and how Stuff & Substance addresses the
Issues in the section on 'Features of Students' Understanding' in the Teachers’ Guide.

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Notes on the video

Students need to understand that the hot syringe does not contain anything before the water is injected, and that at the end of the video there is still no air in the syringe, only water. This is important because students may find it difficult to accept that the only particles in the syringe are water particles unless this is established.
Students should notice that the syringe plunger moves, even though they cannot see anything pushing it, so whatever is in there takes up a lot of space.

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main content c1.2

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tgc1: notes
tgc2: water
tgc3: boiling water
tgc4: boiling point
tgc5: using ideas 1
tgc6: using ideas 2

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