IOP Institute of Physics

Apparatus

Activity 1. Demonstration

See notes about safety for neodymium magnets. Note: for iron wire use florists wire.

Activity 2. Class experiment

• 1 bar magnet per group
• A selection of objects made of different materials eg some bright plastic objects, wooden spoon, cheap steel spoon, enamel cup, plastic cup, copper ornament, cardboard, brass candlestick, wire coat hanger (end bent round so not sharp), a twist of florist’s wire (almost pure iron).

Note: Modern 1p and 2p coins are made from copper-plated steel.

To aid the discussion, it is useful to have some examples of the same type of object made of different materials.

Activity 5. Class experiment

• A second bar magnet per group

Activity 6. Demonstration

• A bar magnet with a long fine thread (nylon fishing line or invisible thread) tied around it so that it will hand horizontally and swing freely. A paper sling could be used so that the magnet balances horizontally.

Note: if sewing thread is used then it is difficult to ensure that the twist has been removed so that the magnet does not rotate continuously.

Activity 7. Demonstration

• Overhead projector (OHP)
• Magnet
• Small paperclips or dressmakers’ pins
• Plotting compasses- – should be transparent – i.e. clear on both sides

Activity 10. Game A

Per group:

• A plotting compass
• Magnet
• Wooden box
• Cardboard box
• Aluminium cooking foil
• Plastic food container
• (variations on this according to availability)

Activity 11. Game B

Per group:

• A plotting compass
• Magnet
• Three iron or steel ‘tins’ or boxes or baking ‘tins’

Note: if there are too few of these for all the groups, then this could be done by one group who explain what happens to the remainder.

Activity 12. Computer memory game – demonstration with pupil involvement (could be omitted)

• Box with a row of 6 deep slots – could be slots in a block of polystyrene from packing
• One magnet per slot
• Cloth or paper to cover magnets
• Plotting compass
• Card to display ‘code’

Activity 13. Demonstration

• Length of copper piping about 1.5 metres long
• Neodymium magnet (see Safety Notes) which slides easily down the pipe
• Block of metal about the same size and shape as the magnet
• Soft pad for magnet to drop on to

Activity 14. Demonstration – electromagnet

• Overhead projector (OHP)
• Length of insulated copper wire
• 1.5 V battery
• Battery holder or magnetic connectors.
• Wires and connections to complete the circuit
• Long nail- (6 inch is best)
• Plotting compasses
• Paperclips

(Note: the nails should not be stored or carried near to the strong magnets as they will become slightly magnetised. If this happens the demonstration that the nails are not magnetised should be avoided.)

Activity 15. Demonstration – kick (could be omitted)

• Length of insulted wire (nonmagnetic eg copper)
• 2 stands
• Battery and connectors
• Switch or means of easily completing the circuit – e.g. crocodile clip
• Neodymium magnet

This needs to be arranged in a position so that the lowest point of the loosely hanging loop of wire can be seen by the whole group.

When the switch is connected the wire is ‘kicked’ sideways.

When the circuit is broken it falls back.

Activity 16. Demonstration - motor

This demo is quite small so find a good place to put this so that the whole class can see without moving closer.

• 1.5 V AA battery
• Neodymium magnet (this is orientated so that the magnetic field is vertical i.e. one pole is at the top and the other at the bottom - could be a button shaped magnet)
• Small iron or steel spacer (not insulated)
• Stiff copper (non-magnetic) wire bent to the shape shown in the picture. The wire must make electrical contact with the spacer. If lacquered wire is used, the lacquer along the middle of the length of the wire must be removed.

Note: the magnetic field is vertical, currents are flowing horizontally through the wire at its lowest point, therefore there are horizontal forces perpendicular to both the currents and the field causing the wire to rotate. This explanation is not needed for the children.

Activity 18.

Demonstration of robot, motorised toys and small devices with motors. Examples: Robot - Climbatron- walks up windows etc. £4.99 travel fan camera with a lens that moves out when switched on. Any devices demonstrated should be checked to ensure they have no sharp edges and do not become hot when working. Only examples using low voltage batteries should be used. Note: Most primary schools have a good number of magnets. However, if conventional bar magnets are not available the ‘sticks’ from a ‘sticks and balls kit’ can be used. They are made with magnets set at each end of plastic ‘sticks.