Thursday 10 November 2011

5.11

5.11 Starter


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· You're looking at smoke particles in air under a microscope
· They appear to be jiggling about
· Why?


· (Don't worry if you can't work this out straight away - Albert Einstein was the bloke who eventually explained what's happening here!)

5.11


· 5.11 understand the significance of Brownian motion


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Model 1
· What does the red puck represent?
· What do the metal balls represent?
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Model 3
· What do the "smoke" particles look like?
· Why are they moving?
· What do the "air" particles look like?

5.11 explained


Model 1
· What does the red puck represent?
o The large, visible smoke particle
· What do the metal balls represent?
o The small, not visible air particles

Model 2
· What do the small red particles represent?
o The small, not visible air particles
· What does the large blue particle represent?
o The large, visible smoke particle
· What does the view on the left of the screen represent?
o The view through the microscope lense
· Why can‘t you see the red particles in this view?
o They are too small to see

Model 3
· What do the "smoke" particles look like?
o They are the 5 large, sand coloured particles
· Why are they moving?
o Small, fast moving air particles are colliding with the smoke particles and making them move
· What do the "air" particles look like?
o They are the numerous, small, white particles

5.11 Questions


1. Draw the path of a smoke particle in air (3 marks)
2. Explain what is meant by Brownian Motion of smoke particles in air and how it provides evidence for air particles (4 marks)
3. What change would you expect to see in the movement of the smoke particles if the air was cooled down? Why? (2 marks)

brownian_motion.swf Download this file

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