ScienceYear 8 Physics

Magnetism and Electromagnetism

Notes & Experiments

Name: ________________Teacher: ______________

YOU MUST KEEP THIS BOOK

MY UNDERSTANDING CHECKLIST

[INSERT SCHOOL LOGO HERE]

I can… Textbook pages(s)

Before the Topic

After the Topic

Magnets and Magnetic FieldsIdentify the two poles on a magnet as north and south 72

Describe how a compass behaves in a magnetic field 72 – 73

Sketch the magnetic field around a single bar magnet 73

Attraction and RepulsionDescribe the difference between attraction and repulsion (with reference to the poles of the magnet)

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Sketch the magnetic fields for the attraction and repulsion of 2 magnets -

Explain the term “Uniform Field” -Building an ElectromagnetDescribe an electromagnet as a non-permanent magnet 74 – 75

Build a simple electromagnet using a nail, wire and a battery 75 – 76

Give 2 way of increasing the strength of my Electromagnet 75

Used of ElectromagnetsExplain the benefits of using an electromagnet 75

Give at least 2 examples of systems which make use of electromagnets. 76 – 77

Explain why an electromagnet is used in one specific system 76 – 77

MY SKILLS CHECKLIST

I can… Before the Topic After the TopicUse a compass to plot a magnetic field around a magnetWrite a clear method for an investigationMake changes to an electromagnet and derive ideas from my observationsResearch a scientific concept and record my findings in a logical fashion

KEY WORDS

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Some of the key words and definitions are missing some information! Can you complete them?

Key Word Image/Diagram DefinitionMagnet A piece of iron or

other material that exhibits properties of magnetism

Permanent Magnet

A magnet that retains its ________ properties in the absence of an inducing field or current.A magnet which can be switched on and off

Poles A bar magnet has two of these. They are called ________ and ________

Attract When two magnets are draw towards each other because they have ____________ polesWhen two magnets are pushed away from each other because they have identical poles

Magnetic Field

a region around a _________ material within which the force of magnetism acts.

Field Lines A visual tool to help represent __________ ________.

Compass A navigation device which always points to __________ ________

Uniform field A magnetic field where the field lines are _____ and _________.

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Lesson 1: Magnets and Magnetic Fields

DEVELOPING IDENTIFY THE TWO POLES ON A MAGNET AS NORTH AND SOUTH

SECURE DESCRIBE HOW A COMPASS BEHAVES IN A MAGNETIC FIELD

EXTENDING SKETCH THE MAGNETIC FIELD AROUND A SINGLE BAR MAGNET

SCIENTIFIC SKILLS USE A COMPASS TO PLOT THE MAGNETIC FIELD AROUND A MAGNET

Do Now: Where do we see magnets?

On the mind map below, write down all the things as you know about magnets?

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MAGNETS

Key Knowledge: What is a Compass?

Your teacher is going to describe a compass to you.

In the space below you should make notes about what you hear and include diagrams where appropriate.

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Investigation: Magnetic Fields

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Diagram:

Health and Safety Check!

Keep magnets away from electronic devices.

What do we call the 2 poles on a bar magnet?

1. N________2. S________

In what direction do magnetic field lines point:

__________ to __________

Results: Magnetic field around a bar magnet

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Investigation: Findings are Conclusions

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1. In the space below, sketch the correct shape of the magnetic field around a bar magnet.

2. Can you describe in words the shape of the magnetic field around a bar magnet?

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3. Do the lines ever cross each other? Why do you think this might be?

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4. How do you think the magnetic field lines would change if the magnet was stronger?

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Sketch your idea in the space below:

5. How would your field lines change if you flipped the magnet over? [What would stay the same? What would change?]

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Lesson 2: Attraction and Repulsion

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True North and Magnetic North

STRETCH

DEVELOPING DESCRIBE THE DIFFERENCE BETWEEN ATTRACTION AND REPULSION (WITH REFERENCE TO THE POLES OF THE MAGNET)

SECURE SKETCH THE MAGNETIC FIELDS FOR THE ATTRACTION AND REPULSION OF 2 MAGNETS

EXTENDING EXPLAIN THE TERM ‘UNIFORM FIELD’SCIENTIFIC SKILLS WRITE A CLEAR METHOD FOR AN INVESTIGATION

Do Now: Test your Magnet Knowledge

Investigation: Magnetic Fields between Magnets

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Health and Safety Check!

Keep magnets away from electronic devices.

Again we are going to use a compass to plot the magnetic field around a magnet (or two!).

Using your knowledge from last lesson, write a method for how to use a compass to plot the magnetic field between two magnets.

Remember: You should include names of equipment and your instructions should be logical and easy to follow. [You may wish to use a diagram to help explain yourself.]

METHOD:

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Results:

Use the next two pages to plot the magnetic fields for the following magnet arrangements:

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Diagram:

A (attract) B (repel) C STRETCH D STRETCH

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Investigation: Findings and Conclusions

Use your investigation results to answer the following questions:

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1. Sketch the correct fields for attraction [A] and repulsion [B] below:

2. The field between the magnets in A is called a Uniform Magnetic Field. Can you describe a uniform magnetic field below?

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3. Can you use the shape of the Uniform Magnetic Field to explain why magnets of opposite poles are attracted to one another.

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4. Describe the magnetic field obtained in set up B [repulsion).

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5. Can you use the shape of this magnetic field to explain why magnets with the same poles facing each other repel?

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6. The magnets have been flipped around in the picture below. Can you sketch the shape and direction of the new magnetic fields.

Worksheet: Magnets Word Search

Below is a Word search with a difference. Can you find the words linked to magnets and write clues for them

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15Magnetic Pigeons

STRETCH

Lesson 3: Building Electromagnets

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Magnetic Pigeons

DEVELOPING DESCRIBE AN ELECTROMAGNET AS A NON-PERMANENT MAGNET

SECURE BUILD A SIMPLE ELECTROMAGNET USING A NAIL, WIRE AND A BATTERY

EXTENDING GIVE 2 WAYS OF INCREASING THE STRENGTH OF AN ELECTROMAGNET

SCIENTIFIC SKILLS MAKE CHANGES TO AN ELECTROMAGNET ANS DERVIVE IDEAS FROM OBSERVATIONS

Do Now: Electric Circuits

Using your Year 7 knowledge, can you draw a circuit below that allows you to switch a light bulb on and off?

You may wish to use the following information to help you:

Component Symbol

Cell

Switch

Lamp

Can you create a circuit which allows you to switch 2 bulbs on and off independently?

Key Fact: What is an Electromagnet

Your teacher is going to describe electromagnets to you.

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STRETCH

In the space below you should make notes about what you hear and include diagrams where appropriate.

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Investigation: Building and Electromagnet

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Diagram:

Health and Safety Check!

Electromagnet can get hot!Switch off between uses to reduces heating.

Before you begin to build your electromagnet make sure you have completed the health and safety box and have labelled the diagram below:

You are going to investigate the effect of changing:

1. The Number of Turns in the Wire2. The Size of the Current3. The Type of Core

Complete your prediction below:

Investigation: Results

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Planning : How will you carry out the investigation?

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Recording your Results:In the space below, you will need to sketch a table to take your results in.

Considering your results/conclusionsWhat did you discover?

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STRETCH

Lesson 4: Uses of Electromagnets

DEVELOPING EXPLAIN THE BENEFITS OF USING AN ELECTROMAGNET

SECURE GIVE AT LEAST 2 EXAMPLES OF SYSTEMS WHICH MAKE USE OF ELECTROMAGNETS

EXTENDING EXPLAIN WHY AN ELECTROMAGNET IS USED IN ONE SPECIFIC SYSTEM

SCIENTIFIC SKILLS RESEARCH A SCIENTIFIC CONCEPT AND RECORD MY FINDINGS IN A LOGICAL FASHION

Do Now: Knowledge and Revision Quiz

1. In the space below sketch a label an electromagnet. [5]

2. Give 2 benefits of using an electromagnet over a permanent magnet? [2]

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3. A boy claps near to a wall. He hears an echo of his clap 3 seconds later. How far away is the wall? (Speed of sound is 340 m/s) [3]

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4. For each of the forces below, state if they are contact or non-contact forces. [4]a. Weight: …………………………b. Magnetic: …………………………c. Upthrust: …………………………d. Friction: …………………………

5. What are the units of Energy? [1] ………………………..

Score [ /15]

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Independent Research: Uses of Electromagnets

You are going to research 2 different uses for Electromagnets. Use the success criteria on the next page to help guide your research.

Remember: Present your ideas in a logical and clear format so that someone else can interpret what you have found.

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Success Criteria Self Check

Peer Mark

Clear description of 2 uses (Grade C)Diagrams to help aid understanding (Grade B)Examples given for how this is used in the real world (Grade B)Advantages and/or Disadvantages of using the electromagnet give (Grade A)One of the examples has a clear explanation of how the circuit works (Grade A)References are given to allow you to cross check information (Grade A*)Suggested a way of improving an existing system (Grade A^)

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STRETCH

Magnetism and Electromagnetism: Past Paper Questions

Q1.          Sam made a model cat.

          He mixed modelling powder with water.

          He poured all of the mixture into a mould.

          He covered the mould with plastic film so that water could not evaporate.

(a)     (i)      After 10 minutes, Sam removed the model cat from the mould.

                    

         Sam had mixed 40 g of modelling powder with 12 g of water.What was the mass of the model cat?

................. g

(ii)     Complete the sentence below using words from the list.

                   gas             liquid         solid           vapour

         After 10 minutes, the mixture in the mould changed from a

.......................................... into a .............................................

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2 marks

(b)     Sam attached a small magnet to the model cat.The magnet was attracted to the fridge door.

          What metal are magnets made from?

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1 mark

(c)     Sam made another model, B. He attached a small magnet to model B.

(i)      Sam placed model A next to model B. The magnets attracted each other.

         Label the poles on the magnet on model BUse the letters N and S.

(ii)     Sam then turned the magnet on model A around.What would happen to model B?

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2 marks

maximum 5 marks

 

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Q2.          Alex makes an electromagnet.She winds insulated wire around an iron nail.She connects the wire to a power supply.She uses the electromagnet to pick up some steel paper-clips.

          This is her prediction.

 

The more turns of wire around the iron nail the strongerthe electromagnet becomes.

(a)     (i)      Give the one factor she should change as she investigates her prediction.

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1 mark

(ii)     Give one factor she should keep the same.

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1 mark

(iii)     Describe how she could use the paper-clips to measure thestrength of the electromagnet.

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1 mark

(b)     Alex wrote a report of her investigation.

          What would an odd result suggest?

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1 mark

(c)     (i)      Which size paper-clips would Alex use to make her results moreaccurate?Tick the correct box.

1 mark

(ii)     Give a reason for your choice.

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1 mark

maximum 6 marks

 

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Q3.          The diagram below shows a pen.

          The pen is held up by two magnets, one in the stand and the other in the pen.

(a)     On the dotted lines above, label the North pole and the South pole of themagnet in the pen.

          Use the letters N and S.

1 mark

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(b)     John put a block of metal between the two magnets as shown below.

          The block of metal became a magnet.

(i)      On the dotted lines above, label the North poles and the South poles ofboth the block of metal and the magnet.

         Use the letters N and S.

1 mark

(ii)     What metal could the block be made of?

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1 mark

(c)     John repeated the experiment using a piece of wood instead of a block of metal.The pen did not stay up.Give the reason for this.

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1 mark

maximum 4 marks

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Q4.          Hannah has three rods (A, B and C) made from different metals.One rod is a magnet; one is made of copper; and one is made of iron.She does not know which rod is which.

          Each rod has a dot at one end.

(a)     Hannah uses only a bar magnet to identify each rod.She puts each pole of the bar magnet next to the dotted end of each rod.

          Complete Hannah’s observations in the table below.Write if each rod is copper, iron or a magnet.

 

test observations type of rod

attract

attract

 Rod A is

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nothing happens

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 Rod B is

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attract

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 Rod C is

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3 marks

(b)     Hannah uses the iron rod to make an electromagnet.

                                    

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          When the switch is closed the iron rod becomes an electromagnet.Give two ways Hannah could make the electromagnet stronger.

1. ..................................................................................................................

1 mark

2. ..................................................................................................................

1 mark

maximum 5 marks

 

Q5.      A compass needle is a small magnet with a North pole, N, and a South pole, S.

          Ruth placed two compasses onto a piece of card.Both compass needles pointed in the direction shown below.

(a)     Ruth placed a bar magnet with its South pole between the two compasses.The compass needles moved as shown below.

          On the diagram below, label the North pole and South pole of each compass needle. Use the letters N and S.

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1 mark

(b)     Ruth turned the bar magnet round so that the North pole was between the two compasses.

          On the diagram below, label the North pole and South pole of each compass needle now.Use the letters N and S.

1 mark

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(c)     Ruth repeated her experiment with an aluminium bar instead of a bar magnet.

What happened to the compass needles?

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1 mark

maximum 3 marks

Q6.          Ali made a cat-flap to fit into a door.

(a)     (i)      On the diagram above, draw an arrow to show the direction of the force of the cat’s head on the cat-flap.

1 mark

(ii)     Add a label to the diagram to show the pivot of the cat-flap.Label it P.

1 mark

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          When the cat has gone through the cat-flap, the weight of the cat-flap makes the flap close.

(b)     Ali used two bar magnets to keep the cat-flap closed, so that it does not blow open in the wind.

          On the diagram above, label both the North and South poles on the magnet inthe cat-flap.

1 mark

(c)     Friction at the pivot made the cat-flap squeak. What could Ali put on the pivot to make the friction less?

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1 mark

Maximum 4 marks

 

 

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Q7.          (a)     The diagram shows two bar magnets.

          The north pole and south pole are shown on magnet A. The poles are not shown on magnet B.

          Describe an experiment you could do, using magnet A, to find which end of magnet B is the north pole and which is the south pole.

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3 marks

(b)     The diagram shows a wooden truck near a wall. There is a strong magnet fixed to the wall and a strong magnet fixed to the front of the wooden truck.

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          James holds the wooden truck so that it does not move.Then he lets go of the wooden truck. In which direction will it move?

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1 mark

(c)     James removes the magnet from the wooden truck. He gives the truck a push so that it rolls along the table.

          What effect will friction have on the speed of the truck as it rolls along?

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1 mark

Maximum 5 marks

 

 

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Extra Notes Space

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