SYLLABUS – Chapter 4
Topic: / Objectives: Students -4. Electricity and magnets:
The simple electric circuit (using dry cells, torch-light bulbs and connecting wires only), conductors and insulators;
The structure and working of the simple light bulb and the simple switch;
The structure of a dry Leclanché cell; polarity, voltage as an indication of power available, use of a battery of cells in series to obtain higher voltages;
The structure and working of a simple torch-light;
Circuit diagrams (limited to components named above);
Magnets, magnetic materials, making a magnet (single touch method only);
Magnetic poles, attraction and repulsion between poles;
The magnetic compass;
Simple idea of magnetic fields including the earth's magnetic field. / • describe some of the ways in which modern life depends on electricity.
• avoid playing or experimenting with mains electricity.
• explain and use correctly the words in italics below.
• make good electrical connections with wires, bulbs and cells using available terminals, holders etc.
• state that (i) a bulb lights up when an electric current flows through it, (ii) an electric current can flow around a circuit only if the circuit is complete, (iii) the current flowing in a circuit leaves one terminal of a cell and returns to the opposite terminal.
• state as a generalisation, that metals and graphite are electrical conductors and most other materials are insulators.
• classify common materials as conductors or insulators.
• describe the structure of a simple bulb and bulb holder, and a simple switch, and explain how they work.
• distinguish between the terms cell and battery.
• describe the simple structure of a dry Leclanché cell and identify the + and - terminals.
• state that the voltages of a Leclanché cell is 1.5 volts.
• connect cells in series and state the voltage of the resulting battery of cells.
• state that voltage relates to the "power" available from a cell or battery.
• list some common types of cells and batteries, state their voltages, and identify some of their common uses.
• take apart a torch, describe how it works, change the cells and the bulb, and reassemble it so that it still works.
• draw and interpret simple circuit diagrams (conductors, bulbs, switches, resistors and cells only).
• make magnets by the method of stroking.
• define magnetic materials as those attracted by a magnet.
• classify iron, steel, cobalt and nickel as magnetic materials.
• state that one end of a freely suspended magnet will point approximately north, and name this the north pole and the opposite end the south pole of the magnet.
• use correctly the words attract and repel in regard to magnets.
• demonstrate, and state as a generalisation, that like magnetic poles repel and unlike poles attract.
• describe the basic construction and use of a simple pocket compass and a ship's compass.
• state, and indicate the directions represented by, the cardinaland inter-cardinal points, of the compass.
• describe how degrees of arc are used to indicate direction, and convert the cardinal and inter-cardinal points into degrees.
• explain what a lodestone is and how it was used.
• explain what is meant by magnetic variation and magnetic north.
• explain, and use correctly, the term magnetic field.
• plot magnetic fields using plotting compasses and iron filings.
• draw from memory, the magnetic fields of a bar magnet, and of pairs of bar magnets together.
• describe the magnetic field of the earth and give a simple explanatory models for this.
• predict the magnetic field of a horse-shoe magnet (given that it is just a bar magnet with a sharp bend in it).
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