Describe how the resistance of a Show students one or more models proxy for filament lamp changes with voltage. for electrical resistance. A simple temperature. Explain why the resistance of a physical model can be made using a filament lamp increases with ping-pong ball rolling down a shallow increasing voltage. ramp. Working Scientifically Round numbers to a given number of Plenary: Thinking about resistance decimal places or significant figures. Consider All Possibilities: A circuit is Decide on an appropriate level of changed so that the current through accuracy before rounding numbers. a bulb decreases. (Possible answers: the voltage of the cell/power supply is reduced; more bulbs are added to the circuit; a resistor is added to the circuit; the bulb is changed for one with a higher resistance.) Lesson 9Je: Electromagnets Learning objectives Exemplar teaching activities Differentiation Resources Maths skills Practical skills Developing Starter: Homopolar motor Explaining: Motor Resources n/a Students build a Describe the shape of the magnetic Make a simple homopolar motor effect from 9Je simple electric field around a wire carrying a current. (from a cell, a small magnet and demonstration Exploring motor of the Describe an electromagnet and the some wire) and show it to students. Introduce Science. ‘Westminster shape of its magnetic field. Encourage them to come up with a students to pattern’, using Describe how the strength of an list of questions, such as: ‘What is the Fleming’s a motor kit. electromagnet can be changed. wire for?’, ‘What shape is the rule (they Explain how electromagnets are used magnetic field of the magnet?’, ‘Is are not expected Demonstrate in simple applications. there a current in the wire?’. to remember the motor Securing this). effect. Explain how changing the size or Exploring: Make a motor direction of the current affects the Give students motor kits (available magnetic field. from equipment suppliers) and ask Explain how electromagnets are used them to build a simple electric motor in relays. of the ‘Westminster pattern’. Describe how a wire carrying a current must be oriented in a magnetic field to Explaining: Motor effect produce a force. demonstration
Describe how the resistance of a filament lamp changes with voltage. Explain why the resistance of a filament lamp increases with increasing voltage. Working Scientifically Round numbers to a given number of decimal places or significant figures. Decide on an appropriate level of accuracy before rounding numbers. Show students one or more models for electrical resistance. A simple physical model can be made using a ping-pong ball rolling down a shallow ramp. Plenary: Thinking about resistance Consider All Possibilities: A circuit is changed so that the current through a bulb decreases. (Possible answers: the voltage of the cell/power supply is reduced; more bulbs are added to the circuit; a resistor is added to the circuit; the bulb is changed for one with a higher resistance.) proxy for temperature. Lesson 9Je: Electromagnets Learning objectives Exemplar teaching activities Differentiation Resources Maths skills Practical skills Developing Describe the shape of the magnetic field around a wire carrying a current. Describe an electromagnet and the shape of its magnetic field. Describe how the strength of an electromagnet can be changed. Explain how electromagnets are used in simple applications. Securing Explain how changing the size or direction of the current affects the magnetic field. Explain how electromagnets are used in relays. Describe how a wire carrying a current must be oriented in a magnetic field to produce a force. Starter: Homopolar motor Make a simple homopolar motor (from a cell, a small magnet and some wire) and show it to students. Encourage them to come up with a list of questions, such as: ‘What is the wire for?’, ‘What shape is the magnetic field of the magnet?’, ‘Is there a current in the wire?’. Exploring: Make a motor Give students motor kits (available from equipment suppliers) and ask them to build a simple electric motor of the ‘Westminster pattern’. Explaining: Motor effect demonstration Explaining: Motor effect demonstration Introduce students to Fleming’s rule (they are not expected to remember this). Resources from 9Je Exploring Science. n/a Students build a simple electric motor of the ‘Westminster pattern’, using a motor kit. Demonstrate the motor effect.
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