Chapter V review and final summary
In Chapter V we studied electrical phenomena. Bodies become electrified by rubbing; there are two kinds of charge, like charges repel and unlike attract. The atom: nucleus (proton +, neutron 0) and electrons (−). Conductors carry charge, dielectrics do not. Electric current is the ordered motion of charged particles; sources: galvanic cell, battery, accumulator, generator (Volta, 1800). A circuit: source, consumer, wires, switch — it must be closed. Current (A) is measured with an ammeter in series, voltage (V) with a voltmeter in parallel. The household mains is 220 V; a safe voltage is up to 36 V. Energy consumption E = N · t, in kWh; saving: LED lamps and switching off unneeded appliances. After an electric shock call an adult, and do not touch sockets or bare wires.
“Circuit diagram”: pupils draw a simple circuit diagram on the board with conventional symbols, showing where the ammeter and voltmeter go; others find mistakes. Safety: on paper only; any real experiment uses a battery (up to 6 V).