5.11

Begin forwarded message:

From: Luke Michael Gebbie <luge14@patana.ac.th>

Subject: Fwd: 5.11

Date: 5 November 2011 10:06:12 PM GMT+07:00

To: "lukephysics@posterous.com" <lukephysics@posterous.com>

Instructions for Objective 5.11

1.    

5.11 Starter.  Watch the video and think about the question.  No need to type anything.

2.    5.11.  Watch the videos and animations for the 3 models of Brownian Motion (for Model 3 you need to open the attached).  Think about the questions.  No need to type anything. 

3.    5.11 explained.  Check your understanding with the model answers.

4.    5.11 Questions.  Forward this e-mail to your blog and complete the questions.

5.    Answers to step 2 will be sent separately.  Don’t look at them until you’ve done the work!

5.11 Starter

02 November 2011

16:58

	<<Video - Brownian Motion smoke in air.wmv>>

·         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

28 October 2011

11:10

·         5.11 understand the significance of Brownian motion

	<<Video - Model of Brownian motion.wmv>>

Model 1

·         What does the red puck represent? the smoke particles 

·         What do the metal balls represent? the air particles 

t

			<<brownian_motion.swf>>

Model 2

red - air 

blue - smoke 

Left picture - what we see on a microscope - showing that the red pictures are too small to see on a microscope 

Model 3

·         What do the "smoke" particles look like? - the 5 large sand coloured particles 

·         Why are they moving? - the air particles are colliding with the smoke, giving them kinetic energy 

·         What do the "air" particles look like? theres a lot of them and they are small white particles 

5.11 explained

28 October 2011

11:10

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

02 November 2011

17:21

1. Draw the path of a smoke particle in air  (3 marks) - vibrates and moves in a random direction

2. Explain what is meant by Brownian Motion of smoke particles in air and how it provides evidence for air particles  (4 marks) 

Brownian motion is where smoke particles move in a random motion without and outer force exertion. This happens because of the already vibrating air particles collide with the smoke particles, causing them to move When we see the smoke particles move, we know that there are air particles around it. 

3. 

What change would you expect to see in the movement of the smoke particles if the air was cooled down?  Why?  (2 marks)

they would not move as fast, this is because the cooled air causes the kinetic energy to decrease, this means that the smoke particles will not move as fast,