6.7

Tell the person next to you…

1. If the field lines are close together, what does this tell you about the field?

2. If the field lines are widely spaced, what does this tell you about the field?

3. If the magnetic field lines are parallel to each other, what does this tell you about the field?

Answers

1.              The field is strong

2.              The field is weak

3.              The field is of a constant strength - a "uniform" field

6.7 know how to use two permanent magnets to produce a uniform magnetic field pattern

When the field lines are parallel, the field will be uniform (constant field strength)

See the full gallery on Posterous

6.6 (no gallery)

6.6 sketch and recognise the magnetic field pattern for a permanent bar magnet and that between two bar magnets

6.4

6.4 understand the term ‘magnetic field line’

Observing the magnetic field around a bar magnet and a wire

magnetic field around a bar magnet and wire

Use iron filings to observe the magnetic field around a bar magnet

Use plotting compasses to observe the field

 Use the 3D field demonstrator to observe field

6.4 Field around bar magnet simulation

Website:

http://www.walter-fendt.de/ph14e/mfbar.htm

<iframe src="http://www.walter-fendt.de/ph14e/mfbar.htm" style="border:0px #FFFFFF none;" name="myiFrame" scrolling="yes" frameborder="1" marginheight="0px" marginwidth="0px" height="800px" width="800px"></iframe>

6.4 plenary questions and Earth's Magnetic Field

6.4 plenary 2

·         

Can you stop a magnetic field?

·         Watch the incredible flying paperclip demo to find out!

·         Now you can try with your hand…

Plenary questions and the Earth's Magnetic field.ppt Download this file

6.5 and 6.3

  

6.5 starter

Demo

·         How I turned a needle into a compass to find my way out of the jungle...

·         6.5 understand that magnetism is induced in some materials when they are placed in a magnetic field

·         6.3 recall the properties of magnetically hard and soft materials

Practical

1.      Stroke a magnet along a steel bar and an iron bar

2.      Try picking up some bar clips

3.      Bang both bars on the desk

4.      Now try picking up the paperclips again

5.      Repeat the experiment but this time put the bars inside an electromagnet instead of stroking them

Explanation

·         Steel is a magnetically hardmaterial.  It retains its magnetism when magnetised

·         Iron is a magnetically softmaterial.  It can be magnetised, but easily loses its magnetism

6.2

6.2 Starter

Neodymium magnets are strong…

6.2 starter 2

·         

Magnetic materials are attracted by magnets.

·         Can you list the 5 magnetic materials? 

(3 elements, 2 compounds)

Answer

 

3 elements

1.          Fe (iron)

2.          Co (cobalt)

3.          Ni (nickel)

 

2 compounds

1.          Steel (an alloy of iron)

2.          Fe₃O₄ (magnetite (lodestone), one of the oxides of iron)

 

And the exceptions that prove the rule…    ?

·         Magnet moves water - diamagnetism

·         Levitating frog...

·         Ferrofluids…

(Picture on page "6.4 6.5 6.6 6")

·         6.2 recall that magnets repel and attract other magnets, and attract magnetic substances

Question

You have 3 bars that all look the exactly the same but they are made from:

1.      a magnet

2.      steel

3.      aluminium

You are given a horseshoe magnet.  How can you use this to tell which bar is which?

Answer

1.          The bar magnet will be attracted to one pole of the horseshoe magnet and repelled by the other

2.          The steel bar will be attracted to both poles of the horseshoe magnet

3.          The aluminium bar will be attracted to neither pole of the horseshoe magnet

6.2 Plenary - Multichoice questions

Attraction and repulsion quiz.swf Download this file

6b Plenary Multichoice questions.pptx Download this file

5.19 Boyle's Law (no gallery)

·         

5.19 use the relationship between the pressure and volume of a fixed mass of gas at constant temperature:

                 p₁V₁ = p₂V₂

p₁ = Pressure at the beginning [kPa, bar or atm]

V₁ = Volume at the beginning [m³ or cm³]

p₂ = Pressure at the end [kPa, bar or atm]

V₂ = Volume at the end [m³ or cm³]

(Note: can use any units for V and p as long as they are the same at the beginning and end)

Fun with the vacuum pump!

·         

Marshmellows

·         Food colouring in pipettes

·         Surgical gloves

5.19 Ideal graph and conclusion

5.19.docx Download this file

5.19 Experiment

·         

Change the pressure of a fixed mass of gas at a constant temperature

·         Measure the volume

·         Use the EXCEL spreadsheet to analyse your results

Ideal Gas - Boyle's Law.xlsx Download this file

5.17-5.18

5.17-5.18.docx Download this file

5.17

Why do the eggs get sucked into the bottles?!

Explanation

·         The burning paper in the bottle heats the air in the bottle

·         When the egg gets placed on top, the oxygen supply in the bottle is rapidly depleted and the paper goes out

·         The bottle is sealed by the egg and now has a constant volume of gas inside

·         The hot gas in the bottle now starts to cool which reduces the pressure inside the bottle

·         The pressure outside the bottle remains unchanged and so there is now an unbalanced force on the egg which accelerates the egg into the bottl
e

·         5.17 describe the qualitative relationship between pressure and Kelvin temperature for a gas in a sealed container

Instructions

·         Launch the application on this website:http://phet.colorado.edu/en/simulation/gas-properties

·         

Put 5 pumps of gas in

·         Set volume as the Constant Parameter

·         Heat to 1000K

·         Watch what happens to the Pressure

 

Conclusion

·         If you increase the temperature, you increase the pressure

Video - Egg sucked into a bottle by Guy-Lussac's Law.flv Watch on Posterous

5.18 Gay-lussac's law

5.18 Gay-lussac's law.docx Download this file

5.16

5.16.docx Download this file

5.16

5.16.docx Download this file

5.14

5.14.docx Download this file

5.14

·         

5.14 describe the Kelvin scale of temperature and be able to convert between the Kelvin and Celsius scales

Converting Centigrade to Kelvin
T_K = T_oC + 273

Converting Kelvin to Centigrade
T_oC = T_K - 273

T_K = Temperature in Kelvin [K]

T_oC = Temperature in Degrees Centigrade [^oC]

5.14) Kelvin Scale & Absolute Zero.docx Download this file

PhET Gas Properties simulation

Click to Run

5.13

5.13 Starter

·         

How can you fit a giraffe, 2 dogs and a swan into a standard laboratory beaker?!

5.13 Starter 2

·         Use particle theory to explain why the gas in the balloon contracts

 

Explanation

·         The temperature of the gas inside the balloon decreases so the average speed of the particles decreases

·         Consequently the gas particles collide with the walls of the balloon with less force and less collisions per second

·         Because the walls of the container are flexible, the  volume decreases

5.13 Charles' law

28 October 2011

11:10

·         5.13 understand that there is an absolute zero of temperature which is –273^oC

	<<Charles' law interactive experiment.swf>>
			Open the Charles' law interactive experiment ·         Adjust the temperature ·         What’s the relationship between temperature and volume? ·         Plot a graph of V against T ·         Take a screen shot of the graph

5.13 results and conclusion

28 October 2011

11:10

Conclusion

·         Volume is directly proportional to absolute (Kelvin) temperature

·         V Î± T

Charles' law interactive experiment.swf Download this file

5.11

5.11 Starter

·         

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

Model 1

·         What does the red puck represent?

·         What do the metal balls represent?

			<<brownian_motion.swf>>

Model 3

·         What do the "smoke" particles look like?

·         Why are they moving?

·         What do the "air" particles look like?

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

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

5.12 + 5.15

This e-lesson consists of 3 objectives; 5.12, 5.15 and 5.11.  I’ll e-mail the other objective separately.

Instructions for Objective 5.12 and 5.15

1.    

5.12+5.15 Starter.  Watch the video and think about the question.  No need to type anything.

2.    5.12+5.15 Questions.  Open the animation.  Forward this e-mail to your blog and complete the questions.

3.    5.12+5.15 Plenary.  Open the attached ppt.  View as slide show.  Think about what the blanks in the table are.  Check your answers with slide 2.  No need to type anything.

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

Best wishes,

Mr B

5.12+5.15 Starter

	<<Video - simulation of gas pressure in Phun.flv>>

Questions

·         Why does the needle on the meter move when gas particles are introduced into the box?

·         What does the meter measure?

Answers

·         The gas particles collide with all of the walls of the container.  The wall on the right moves outwards and moves the needle.

·         Pressure.  The gas particles colliding with the walls makes a force on the walls.  The walls have a surface area so the quantity measured is pressure, p=F/A.

5.12+5.15 Questions

·         

5.12 recall that molecules in a gas have a random motion and that they exert a force and hence a pressure on the walls of the container

·         5.15 understand that an increase in temperature results in an increase in the speed of gas molecules

Try the animation 

http://www.lon-capa.org/~mmp/kap10/cd283.htm

1.    How do the particles create a pressure?

Because gas molecules are moving around at random motion, they eventually collide into the wall of the container, exerting force on its surface.

2.    

If you increase the temperature, how does the movement of the particles change?

The speed of the movement of gas molecules increases due to the increase in average kinetic energy.

3.    

If you increase the temperature, how does the number of collisions per second change?

The collisions per second increases.

4.    

If you increase the temperature, what does this do to the pressure?

The pressure increases due to the increase in kinetic energy, which increase the collision of gas molecules to the wall. As a result, more force is being exerted onto the wall of the container and therefore pressure increases. 

5.12+5.15 Plenary

<<Ideal gases - summary of terms.pptx>>

Ideal gases - summary of terms.pptx Download this file