1. Electromagnetism
Concepts:
The Motor Effect
Induction

2. The Motor Effect 04/04/2019 Aim: To use Flemming’s Left Hand Rule
To explain how a motor works
To construct a motor

3. Fields Bar Magnets
handout

4. Opposite Poles

5. Same Poles

6. Fields due to Current

7. Single Coil of Wire
Solenoid

8. Magnetic Field Lines Movie There are magnetic field lines around every
Electrical wire (with current flowing through it)
Anything magnetic in the field will experience a force
Movie

9. Wire in a magnetic field
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
This virtual experiment can be used as an introduction to the motor effect or as a revision exercise.

10. The Catapult (Motor) Effect

11. Motor Effect
If a conductor carrying an electric current moves through magnetic field lines at right angles it will experience a force.
A charged particle will experience the same effect

12. Fleming's left hand rule

13. Demo with Motor Effect Apparatus
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
Students should be made aware that the direction of a magnetic field is usually taken as being N-S rather than S-N, and the direction of current is the direction of conventional current, i.e. positive to negative.

14. Increasing the Size of the Force
Boardworks GCSE Additional Science: Physics
Motors and Generators

15. The motor effect: true or false?
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
This true-or-false activity could be used as a plenary or revision exercise on the motor effect, or at the start of the lesson to gauge students’ existing knowledge of the subject matter. Coloured traffic light cards (red = false, yellow = don’t know, green = true) could be used to make this a whole-class exercise.

16. Exam Question

17. Exam Question

18. Coil in a Magnetic Field
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
This activity extends the idea of a current-carrying wire in a magnetic field from slide 4, and introduces the concept of current-carrying coil experiencing rotational force. Students could be asked to interpret the movement of the coil using Fleming’s left-hand rule, and begin to think about how an electric motor works.

19. How does an electric motor work?
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
This activity extends the idea of a simple current-carrying coil rotating in magnetic field from slide 8, and explains how a split-ring commutator enables a coil to continue rotating. Students could again be asked to interpret the movement of the coil using Fleming’s left-hand rule.

20. Boardworks GCSE Additional Science: Physics Motors and Generators
Demo Motor
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
Students should be made aware that the direction of a magnetic field is usually taken as being N-S rather than S-N, and the direction of current is the direction of conventional current, i.e. positive to negative.

21. DC electric motor simulation
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
This simulation takes the concepts from the previous slide to create an animated motor simulation. The current, forces and magnetic field can be toggled on and off, to aid visualization and understanding, and the speed and direction of rotation can be altered.

22. How do we increase motor strength?
Boardworks GCSE Additional Science: Physics
Motors and Generators
How do we increase motor strength?
Would the same strength motor be used in both of these?
How can the strength of an electric motor be increased?
Photo credits: © 2007 Jupiterimages Corporation
increase the current flowing through the coil
increase the strength of the magnet
increase the number of turns on the coil
Worksheet

23. The Motor Effect recap Aim: To use Flemming’s Left Hand Rule
To explain how a motor works
To construct a motor

24. Induction 04/04/2019 Aim: To observe and define induction
To explain how electricity is generated

25. Exam Question

26. Exam Question

27. Inducing current in a wire
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
This virtual experiment can be used as an introduction to electromagnetic induction or as a revision exercise.

28. What is electromagnetic induction?
Boardworks GCSE Additional Science: Physics
Motors and Generators
Current Carrying Wire + Magnetic field = Motion
Motion + Magnetic field = Current in Wire
Changing Magnetic field = Current in wire
If they are at right angles to each other

29. Inducing current in a coil
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
This virtual experiment can be used as an alternative introduction to electromagnetic induction or as a revision exercise.

30. Boardworks GCSE Science: Physics Electricity to the Home
Induction
Boardworks GCSE Science: Physics
Electricity to the Home
If a magnet is moved near a coil of wire a current is induced in the wire
Faster motion, bigger current
Stronger magnet, bigger current
More turns, bigger current
Change direction of motion, change direction of current

31. Factors affecting induced current
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
Appropriately coloured voting cards could be used with this classification activity to increase class participation.

32. How can motion produce a current?
Boardworks GCSE Science: Physics
Electricity to the Home
Teacher notes
This true-or-false activity could be used as a plenary or revision exercise on electromagnetic induction, or at the start of the lesson to gauge students’ existing knowledge of the subject matter. Coloured traffic light cards (red = false, yellow = don’t know, green = true) could be used to make this a whole-class exercise.

33. Boardworks GCSE Additional Science: Physics Motors and Generators
What are Generators?
Boardworks GCSE Additional Science: Physics
Motors and Generators
A generator is a device that converts mechanical energy into electrical energy. It is the opposite of an electric motor.
Power stations use generators to produce electricity on a large scale.
Mechanical energy is provided by rotating turbines that can be powered by:
high-pressure steam – in coal, oil, gas and nuclear power stations
wind – in wind turbines
falling water – in hydroelectric power stations
Photo credit: Clipper Windpower / National Renewable Energy Laboratory

34. How do AC generators work?
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
This activity extends the idea of simple electromagnetic induction from slides 16 and 19, and explains how slip rings enable a generator to produce alternating current.

35. AC generator simulation
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
This simulation takes the concepts from the previous slide to create an animated generator simulation. The current, forces and magnetic field can be toggled on and off to aid visualization and understanding.

36. Induction: true or false?
Boardworks GCSE Additional Science: Physics
Motors and Generators
Teacher notes
This true-or-false activity could be used as a plenary or revision exercise on electromagnetic induction, or at the start of the lesson to gauge students’ existing knowledge of the subject matter. Coloured traffic light cards (red = false, yellow = don’t know, green = true) could be used to make this a whole-class exercise.

37. What is a transformer? iron core secondary coil primary coil
The voltage of an alternating current can be changed using a device called a transformer.
A transformer contains two coils that are wound around a soft iron core.
iron core
The alternating current in the primary (input) coil produces an alternating magnetic field.
This alternating magnetic field induces an alternating current in the secondary (output) coil.
secondary
coil
primary
coil

38. How does a transformer change voltage?
The voltage induced in the secondary (output) coil depends on the number of turns on the primary and secondary coils.
A step-up transformer has more turns on the secondary coil and so increases voltage.
A step-down transformer has fewer turns on the secondary coil and so decreases voltage.

39. How are transformers used to supply electricity?

40. Transformers Worksheet
Transformers are used to change the voltage from the Primary (input) to the Secondary (output)
They only work with a.c. (alternating current)
Input (Primary) Voltage = Number of Primary Turns
Output (secondary) Voltage Number of Secondary Turns
Example Question:
Input voltage = 230 V
Primary turns = 10000
Secondary turns = 500
What is the secondary voltage?
Worksheet