Concepts concerning electricity are quite wide-ranging at the primary level, covering the nature of electricity, circuit construction, applications of electricity and safety issues. The key points are:
I. Electricity has particular, well-defined properties.
2. It is the power source for many household appliances.
3. It is potentially dangerous, but its risks can be minimised.
4. It is able to flow around an unbroken circuit.
5. Switches can be used in a circuit to make different components do different things.
6. Electricity will affect components arranged in series and in parallel circuits differently.
Teaching Concepts
Click on each concept to see Subject facts, Why you need to know these, Vocabulary, Amazing facts, Common misconceptions, Questions and Teaching Ideas
Concept I : What is electricity?
Concept 2: How do we use electricity!
Concept 3: What can electricity do to you!
Concept 4: Electrical Circuits
It is important to be aware of how these concepts can be developed in teaching. The following is one way in which the progression can be described. It goes up to Key Stage 3, because it is necessary to know where the children will be going next.To demonstrate your own understanding of the concepts, it is useful to produce your own concept chain.
Many everyday items, including toys and appliances, use electricity. Some items use mains electricity and some use batteries; some are able to use both. Mains electricity is potentially dangerous if the correct safety procedures are not followed. Simple circuits can be constructed from batteries and bulbs, connected together using wires. Batteries and bulbs work best if their voltages are closely matched. Buzzers will only operate if connected a particular way around. Most metals are good conductors of electricity. Electrical devices in a circuit will only work where there is a complete conductive path.
Devices in a circuit can be controlled by switches which make and break the circuit. A completed circuit can be explained in terms of the continuous flow of electricity through it. Increasing or reducing the voltage of the battery used in a circuit will affect the operation of devices in that circuit (bulbs will become brighter or dimmer). Placing an additional device in the circuit will reduce the output of each device (for example, if a second bulb is added, both bulbs will be dimmer than the first was alone). A series circuit is one where there is only one path for the flow of electricity to take to complete a circuit. A parallel circuit is one where there is more than one path for the flow of electricity to take to complete a circuit. Devices connected in parallel act as if they were in circuits on their own. Batteries connected to a parallel circuit with two devices will expend their energy more quickly than if the same devices were connected in series.A circuit diagram, with symbols for devices, can be used to represent a circuit. It can also be used as a basis for the construction of a circuit. Placing a variable resistance in series with a device will allow the output of that device to be varied (for example, making a bulb less bright).
The flow of current throughout a series circuit is the same.The sum of the voltages measured at each device in a series circuit will be the same as the output of the battery or power supply connected to the circuit. Voltage (V) is a measure of potential difference (electrical pressure) between the two terminals (or electrodes) of a battery, measured in volts (V), Electrical current (l) is a measure of the flow of electricity through a circuit, measured in amps (A), The resistance to the flow of electricity in a conductor depends on the thickness, length, material and temperature of the conductor. Electrical resistance (R) is measured in ohms (Q), and has a heating effect on the surrounding material. Electrical current, resistance and voltage are linked by the relationship V = IR Power (P), the rate at which electrical energy is used, is related to current and voltage by the relationship P = IV. A conductor is a material in which the electrons can move freely from atom to atom. Electricity is a flow of electrons in a particular direction.The flow of electricity causes an electromagnetic field, which can be used to repel and attract a permanent magnet and so cause movement. Movement of a coil of wire in a permanent magnetic field will cause a flow of electrons in the coil.