Lesson J1: Magnetic fields

Main activities

J1a What do magnets do?

For each group:

·  2 bar magnets

·  small pieces of iron, nickel, copper and aluminium

·  a compass

J1b Magnetic forces

For each group:

Core, Help:

·  selection of magnets labelled A, B, C and D

(A and B should both be ‘strong’ magnets; C and D should be weaker than A and B.)

Extension:

·  four similar rods, labelled W, X, Y and Z, made of iron, brass, wood and a magnet

·  bar magnet

Plenary activities

Looking ahead

·  two bar magnets

·  OHP

·  iron filings

·  acetate sheet (to prevent iron filings touching the magnets)

Lesson J2: Magnets

Starter activities

Capture interest (2)

·  magnet, clamp stand (to hold magnet vertically)

·  thread

·  blu tack

·  paper clip

·  various materials to test, e.g. iron, paper, aluminium, glass

Main activities

J2a Plotting magnetic fields

For each group:

·  bar magnet (two for each Extension group)

·  plotting compass

·  A4 sheet of plain paper

·  sharp, soft pencil

J2b Using a compass to navigate

For each group:

·  map showing location of buried treasure and planned route

·  chalk, tape or small object to indicate the starting point

·  orienteering compass

·  trundle wheel or measuring tape

·  stick (or similar) with group name to mark position of treasure

Lesson J3: Making magnets

Starter activities

Capture interest (1)

·  test-tube two-thirds full of iron filings fitted with a tight stopper

·  strong bar magnet

·  small nails or pins to test that a magnet has been made

Main activities

J3a Making magnets

For each group:

·  steel strip

·  bar magnet (possibly different strengths for different groups)

·  paper clips

·  access to a demagnetising coil carrying alternating current

Help:

·  test-tube of iron filings with a tight-fitting bung (pupils do not remove the bung)

·  strong bar magnet

·  plotting compass (to test for magnetism)

J3b Making a compass

For each group:

·  bar magnet

·  blunt needle or straightened paper clip

·  length of thread

·  filter paper

·  trough of water (large enough to float a needle or straightened paper clip)

·  compass

Plenary activities

Looking ahead

·  long iron nail (or similar)

·  length of insulated wire wound around nail with turns touching and covering most of its length and with a minimum of 10 cm free at either end, two crocodile clips (to attach to ends of insulated wire), two connecting leads, low-voltage high-current power supply (e.g. Westminster type), small pins, paper clips or nails (to show that the nail is magnetised)

Lesson J4: Electromagnets

Main activities

J4a Making an electromagnet

Core:

·  about 1 metre of plastic coated wire stripped at both ends

·  two crocodile clips

·  wooden cylinder (to form a coil of wire)

·  low-voltage dc power supply

·  two connecting leads

·  heat-resistant mat

·  plotting compass

·  blu tack

·  A4 sheet of plain paper

Extension:

·  about 1 metre of plastic coated wire stripped at both ends

·  two crocodile clips

·  low-voltage dc power supply

·  two connecting leads

·  clamp stand, or similar, to support wire in a vertical position

·  plotting compass

·  piece of card (about 15 cm square) with central hole

J4b Adding a core to an electromagnet

For each group:

·  about 1 metre of plastic coated wire stripped at both ends

·  two crocodile clips

·  wooden cylinder (to form a coil of wire)

·  low-voltage dc power supply

·  two connecting leads

·  heat-resistant mat

·  rods of various materials, as decided by the teacher

·  paper clips or iron nails (to test the strength of the electromagnet)

·  access to a demagnetising coil carrying alternating current

Lesson J5: Variables

Starter activities

Bridging to the unit

·  iron cylindrical core

·  low-voltage, high-current power supply and variable resistor or variable power supply

·  two crocodile clips

·  very tiny magnetic objects, e.g. a few iron filings or tiny steel washers

·  a large magnetic object, e.g. large iron weight or large toy car

Lesson J5 Investigate: How to make an electromagnet stronger

Main activities

J5 Investigate: How to make an electromagnet stronger

Core:

·  about 1 metre of plastic coated wire stripped at both ends

·  two crocodile clips

·  wooden cylinder (to form a coil of wire)

·  variable power supply

·  ammeter

·  connecting leads

·  heat-resistant mat

·  iron rod

·  paper clips or iron nails (to test the strength of the electromagnet)

·  access to a demagnetising coil carrying alternating current

Help:

·  about 1 metre of plastic coated wire stripped at both ends

·  connecting leads

·  heat-resistant mat

·  two crocodile clips

·  iron rod

·  wooden cylinder (to form a coil of wire)

·  paper clips or iron nails (to test the strength of the electromagnet)

·  low-voltage dc power supply

5

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