MAGNETISM AND ELECTROMAGNETISM

Ray Langton

YES! REALLY

Oh No! Not another Power Point!

• “Tail End Charlie”• Death by Power Point

My aims in these sessions1. To refresh/reinforce/reinvigorate/re-

assure regarding Physics2. To use practical classroom teaching

methods as exemplars.

How Science Works

• How Science Works

• Ideas and Evidence

Opinions: Pupils should be taught:

• A card sort activity – pupils discuss and differentiate between scientific and non-scientific opinions

To distinguish between statements based on scientific facts and those based on whim or opinion

Opinions

• Scientific: are based on reliable evidence

• Non-scientific: ideas based on whim or opinion

Sort the following opinions into those that are:

Scientific: are based on reliable evidence

Non-scientific: ideas based on whim or opnion

Key ideasOnly a few metals are magnetic

The ends of magnets are called the North and South Pole of the magnet

There is a ‘law of magnets’

Magnets and electro-magnets generate a magnetic force field

Magnetic field lines are invisible, but can be shown to have regular symmetrical patterns

Theory indicates that magnetism in metals is caused by tiny magnetic domains

The Earth has a magnetic field

Magnetism can be induced by an electric current

Electro-magnets have advantages over permanent magnets

The strength of an electro magnetic device can be varied

Electro magnetic induction forms the basis of many useful tools and equipment

WHAT DO I KNOW?

• In groups• On post-its provided jot down ‘bits’ of

knowledge that you remember about magnetism and electro-magnetism

• Put all your post its together and group them

• Ask each other to explain any you don’t understand

Key ideasOnly a few metals are magnetic

The ends of magnets are called the North and South Pole of the magnet

There is a ‘law of magnets’

Magnets and elector-magnets generate a magnetic force field

Magnetic field lines are invisible, but can be shown to have regular symmetrical patterns

Theory indicates that magnetism in metals is caused by tiny magnetic domains

The Earth has a magnetic field

Magnetism can be induced by an electric current

Electro-magnets have advantages over permanent magnets

The strength of an electro magnetic device can be varied

Electro magnetic induction forms the basis of many useful tools and equipment

Red Green Cards/Show thumbs

• First “Who let the dog’s out?”• Thumbs next slide• Red green cards following 3

Attract, Repel or Nothing happens?

N S S N

N S N S

Aluminium N S

SteelN S

PlasticN S

Are these statements correct?

• Like poles attract, unlike poles repel.• A north pole will attract a north pole.• A south pole will repel a north pole.

Show Red for FalseGreen for True

FalseTrueFalseTrueFalse

Earth’s Magnetic FieldWhich is correct?

S N

N S

RED

GREEN

Why is this correct?• Think about the way a

compass points and the rules of repulsion and attraction of magnets.

S N

Sketch the Earth’s Magnetic Field

S N

Objectives

• make an electromagnet• identify independent and

dependent variables• complete practical work carefully

and safely

Today we are learning about electromagnets.By the end of today’s lesson I will be able to:

Question• What question are you asking?

• What is the independent variable

• What is the dependent variable

• What question can you raise linking the two?

Variables

Independent variable

Dependent variable

Control variables

This is the variable that we will change

This is the variable that we will measure

We will keep these variables the same

Draw a graph

(This will bethe average)

Conclusion

I found out that as I increased the independent variable

the dependent variable increased / decreased.

Conclusion

• Any anomalous results? What are these? You can look at your graph or your results table.

• Support your prediction by taking readings from your graph.

• Can you explain your findings using your scientific knowledge?

Evaluation

Look at your line of best fit. The more accurate the points the closer they will be to the line of best fit. The less accurate they are the further away from the line they will be.

Animation Heinemann Interactive

• Animation Electro Magnets Heinemann 2 8J.6 Animation Electro Magnets

ADVANTAGES AND APPLICATIONS OF

ELECTROMAGNETISM

Advantages

Applications

Bells, Buzzers, Relays,

Motors/Generators

Transformers

Key ideasOnly a few metals are magnetic

The ends of magnets are called the North and South Pole of the magnet

There is a ‘law of magnets’

Magnets and electro-magnets generate a magnetic force field

Magnetic field lines are invisible, but can be shown to have regular symmetrical patterns

Theory indicates that magnetism in metals is caused by tiny magnetic domains

The Earth has a magnetic field

Magnetism can be induced by an electric current

Electro-magnets have advantages over permanent magnets

The strength of an electro magnetic device can be varied

Electro magnetic induction forms the basis of many useful tools and equipment

Plenary

• Dear Me

• Reflect on ideas, knowledge, understanding, methods of teaching etc.