Download Starter

Starter and plenary suggestions for Exploring Science Unit 8J
Page 1
Unit 8J – Magnets and electromagnets
8Ja Magnetic attraction
Starter
If any ‘executive toys’ such as floating pens are available, you could use these to initiate
discussion of magnetism and its effects. Practical 1 in the Teacher's Guide for this topic
shows how to set up the ‘floating paper clip’ demonstration, which could also be used to
initiate discussion.
Alternatively, you could carry out a brainstorming or free writing activity, asking pupils to
write what they know about magnets and magnetism.
Plenary
Worksheet 8Ja/2 (in Copymaster File 8) provides a wordsearch activity that could be used as
a plenary if it is not required for homework.
Alternatively, carry out a ‘connectives’ exercise to revise the content of this topic.
Connectives are a set of sentences for pupils to complete in their own words, including one
of the following words: and, because, but, however, such as, therefore, which, to, so.
A set of statements is provided as Worksheet 8Ja/4 (on the website) for pupils to use, or the
worksheet can be copied onto an OHP slide or written on the board. Pupils can be given five
minutes to complete their sentences, and then they can share their ideas with the class.
The obvious answers to many questions involve using ‘because’ as a connective, but more
able pupils should be encouraged to use the other connectives if they can.
Some possible answers are given below, although these are not the only valid responses:
1
A magnet will attract a steel can …because steel is a magnetic material / but it will not
attract an aluminium one / so it can be used to separate aluminium and steel cans
2
Magnetism can pass through paper … which is why fridge magnets work / and also
through other non-magnetic materials / but not through iron
3
Two pieces of metal repel each other … so they must both be magnets / so they must both
be made of magnetic material
4
Two pieces of iron attract each other… so at least one of them must be a magnet
5
Computer discs are coated in iron oxide … because iron oxide is a magnetic material
8Jb Pointing north
Starter
Give pupils copies of worksheet 8Jb/4 (on the website), and ask them to produce questions to
fit the answers given. Pupils can work in small groups before holding a short class discussion
to decide what the questions should be. This can be done orally or in writing.
Possible questions for the answers provided are:
1 Name three magnetic metals.
Exploring Science 8
This material may be adapted for use in schools.
© Pearson Education 2003
Starter and plenary suggestions for Exploring Science Unit 8J
2
3
4
5
6
7
8
Page 2
Name a compound that is a magnetic material.
Give the names of two things that use this magnetic compound.
Why is steel a magnetic material.
What are the two ends of a magnet called?
Which poles of a magnet do you have to put together to make them repel each other?
How can you turn a needle into a magnet?
Name a material that magnetism can go though.
Plenary
Worksheet 8Jb/5 (on the website) can be used to help pupils revise the work from the first
two topics of this Unit. The worksheet provides a set of statements which pupils are asked to
rank as true or false, and to correct any false statements. They should then decide whether
the second statement of each pair explains the first – they should use their corrected versions
for this part of the activity.
For instance:
A
B
Iron cannot be attracted to a magnet.
Iron is a magnetic material.
False
True
Pupils should correct statement A to say that iron can be attracted to a magnet, then say that
B explains the corrected A.
Answers:
A False - iron can be attracted to a magnet
B True
B explains corrected A
C False – the two ends of a magnet are called the north pole and the south pole.
D True
D does not explain corrected C
E True
F False – the Earth acts as if it has a bar magnet inside it (or any other similar statement).
Corrected F explains E
G False – you can show something is a magnet by seeing if it will repel another magnet.
H True
H does not explain corrected G
8Jc Force field
Starter
Worksheet 8Jc/6 (on the website) provides a word puzzle that will help pupils to consolidate
the work of the previous two topics.
Answers:
1
2
3
4
same
cobalt
magnetic
nickel
Exploring Science 8
This material may be adapted for use in schools.
© Pearson Education 2003
Starter and plenary suggestions for Exploring Science Unit 8J
5
6
7
8
9
Page 3
repel
attract
iron
south
compass
Plenary
Ask pupils to summarise the contents of this Unit so far by drawing a concept map. More
able pupils should be able to draw their own maps, but Worksheet 8Jc/7 (on the website)
could be used to help less able pupils.
8Jd Sounds magnetic/Keep your distance
Starter
Show pupils that a bar magnet can pick up a steel can or other object, and discus how this
could be useful in a scrap yard. Discuss how the scrap could be put down again – pupils
should realise that a bar magnet is not practical in these circumstances. You could then
demonstrate an electromagnet, and ask pupils to suggest ways of changing its strength – this
part of the activity will lead naturally into Practical 2.
Plenary
Worksheet 8Jd/9 (on the website) provides material for a ‘spot the mistake’ exercise. The
worksheet provides pictures of a bar magnet with its magnetic field and a starter motor
circuit which can be copied onto acetate for use with an OHP.
The mistakes on the bar magnet are:
 the shape of the field lines - they should be curves
 the directions of the arrows - they should all point away from the north pole and
towards the south pole
The mistakes on the starter motor diagram are:
 the armature should be iron, not copper
 the whole armature moves
 the circuit on the left should be connected to the starter motor
 the top right label should say ‘turning the ignition key makes current flow in the coil’
8Je Coils and cores
Starter
Use the CAP suggestions on the Thinking Skills page for this Unit to revise work covered in
the Unit so far (see the notes on CAP activities on page 10 of Teacher's Guide 7). Allow
pupils five minutes to note down their ideas before reporting back to the rest of the class.
These CAP suggestions, and some additional ones, are reproduced below:
8Ja – Two pieces of metal are attracting each other.
8Jc – A compass needle does not point north.
Exploring Science 8
This material may be adapted for use in schools.
© Pearson Education 2003
Starter and plenary suggestions for Exploring Science Unit 8J
Page 4
8Jd – An electromagnet will not pick up a can of food.
8Jd – An electric bell will not work.
8Jd – A car engine will not start.
Plenary
Worksheet 8Je/7 (on the website) provides a set of cards for a question loop activity that can
be used to summarise the whole Unit, and act as a starting point for revision.
There are 30 cards provided. All cards must be used to close the ‘loop’ – if you do not have
30 pupils in the class, give some pupils more than one card. Alternatively, copy two sets of
cards so that each pupil has at least two cards – two hands should then go up in answer to
every question, and pupils are less likely to mentally switch off when they have used their
card.
Answers:
Name a compound that is a magnetic
material.
Which magnetic material is found in
steel?
Name three magnetic metals.
What are the two ends of a magnet
called?
What will two north poles do if they are
put close together?
What will a north and a south pole do?
How can you make a needle into a
magnet?
Why can’t you prove something is a
magnet if it is attracted to a magnet?
How can you make a magnet into a
compass?
Which materials can magnetism pass
through?
Why do fridge magnets work?
What is a magnetic field?
How can you find the shape of a
magnetic field?
Why can’t you use copper filings to find
the shape of a magnetic field?
Which way do the arrows on field lines
point?
Where is the north magnetic pole?
Why should one end of a magnet really
be called the ‘north-seeking pole’?
Why is a bar magnet sometimes called a
permanent magnet?
Describe two ways of making an
Exploring Science 8
This material may be adapted for use in schools.
Iron oxide.
Iron.
Iron, nickel, cobalt.
North pole and south pole.
Repel each other.
Attract each other.
Stroke it in one direction with a magnet.
An unmagnetised piece of iron would
also be attracted to a magnet.
Hang it from a thread so it can swing.
Anything that is not a magnetic material.
Magnetism can go through paper.
The space around a magnet where it has
an effect.
Using iron filings or a plotting compass.
Copper is not a magnetic material.
Away from the north pole and towards
the south pole.
Near the Earth’s North Pole.
Because it is the end that ‘seeks’ the
north pole of the Earth.
Because you cannot switch the
magnetism off.
Use more coils or a higher current.
© Pearson Education 2003
Starter and plenary suggestions for Exploring Science Unit 8J
electromagnet stronger.
Why won’t a wooden core make an
electromagnet stronger?
What is the moving part in an electric bell
called?
What is the name for the kind of switch
used in an electric bell?
What is a relay?
Why is a relay used in a car starter motor
circuit?
What is the armature in a relay made
from?
What is the name for an electromagnet
that is being used in a relay?
What shape is the magnetic field around
an electromagnet?
How can you change the direction of the
magnetic field of an electromagnet?
What is a reed switch?
How does a reed switch work?
Exploring Science 8
This material may be adapted for use in schools.
Page 5
The core has to be made out of a
magnetic material.
The armature.
A make and break switch.
A switch that can be turned on or off
using a magnet or electromagnet.
So the driver does not have to touch the
circuit that carries a high current.
Iron.
A solenoid.
The same as the shape of the field around
a bar magnet.
Change the direction the current is
flowing.
Two thin pieces of metal inside a glass or
plastic case.
The two pieces of metal become
magnetised, attract each other, and touch.
© Pearson Education 2003