1. Teacher notes - Prior knowledge Describe the shape of a field around a straight wire, solenoid Describe that a current carrying wire at right angles to a magnetic field experiences a force Use Fleming’s left hand rule to predict the direction of a force on a current carrying conductor Use the right hand rule to predict the direction of field around a current carrying conductor

2. motors P2

3. Success Criteria Build a simple dc motor Use Fleming’s left hand rule to explain how your motor spins Use the idea of combining fields to explain how your motor spins

4. 1 Minute Presentation (Mr) (Fleming’s) (Cat)

5. Teacher notes Provide class with a selection of motors collected from old / broken household items (eg. hairdryer, food mixer, tape recorder, video player, drill etc.)

6. Thinking about motors What do they have in common? How do you think they work? Where do you think they are used?

7. Teacher notes Can demo ‘paper clip motor’, ‘screw motor’ and or ‘spiral motor’. Several other examples on you tube http://www.youtube.com/watch?v=UhMkUOWaN3M

8. Teacher notes Introduce the motor kit apparatus. Take pupil suggestions as to how to constuct. Pupil activity: Build motors 2 challenges with appropriate help/explanations follow

9. 10-Jun-16

11. CHALLENGE Use Fleming’s LEFT hand rule to explain how your motor works. (Mr) (Fleming’s) (cat) Motion Field Current

12. N SNS = current out of page = current into page

13. http://www.youtube.com/watch?v=FjNnRyLexNM NS

14. N S CHALLENGE Draw fields around the wires and between the magnets. How do they combine to make your motor spin? Direction of field Direction of current extension

15. The right hand rule You can work out the direction of the field using your right clenched fist. Reversing the direction of the current will reverse the magnetic field direction. Direction of field Direction of current

16. Forces caused by fields NORTH SOUTH MOTION INCREASED FIELD DECREASED FIELD

17. N S Field reduced Field increased

18. Use key ideas from today’s lesson to annotate your diagram

21. Homework activity What is a split ring commutator? Why do practical motors have curved pole pieces?