1. Topic 6: Generators and Motors Science 9 with Mrs M Please take off your hats and hoods

2. Generating Power Most of our power comes from large power plants that convert mechanical energy into electrical energy Remember that question, “why are turbines so important?” We will answer that! Topic 6 Generators and Motors

3. Power Plant Turbine -> Generator The turbine provides enough force to turn the generator’s coil of wires Topic 6 Generators and Motors

4. Electric Generator Device that converts mechanical energy into electric energy Topic 6 Generators and Motors NOTES

5. Generators Electricity and Magnetism are related Topic 6 Generators and Motors NOTES NS

6. Electricity and Magnetism are Related Topic 6 Generators and Motors NOTES

7. How do we know? Compass needle turns when near electric field With more electricity there is a stronger needle deflection = stronger magnetic field Topic 6 Generators and Motors NOTES

8. Reverse the electric current and you reverse the direction of the magnetic field Stop the current = stop the magnetic field

9. Electromagnet When current is passed through a coil of wire wrapped around an iron rod an electromagnet is created North and south poles form on either end of the wire More coils = stronger magnet Topic 6 Generators and Motors NOTES

10. Topic 6 Generators and Motors Electromagnet from a soft iron core that becomes magnetic when current flows

11. Magnetized Material Water has a dipole (North and South) Alignment of “poles” is similar to the alignment of charges. Topic 6 Generators and Motors

12. MRI works on this principle (Magnetic Resonance Imaging) Topic 6 Generators and Motors

13. Earth has a magnetic field

14. The human heart’s electrical impulses create a magnetic field

15. Example of an electromagnet: Maglev Trains

16. Links Using iron filings to observe field of solenoid https://www.youtube.com/watch?v=CZKNl9W BIk4 https://www.youtube.com/watch?v=CZKNl9W BIk4 melt metal with magnets https://www.youtube.com/watch?v=8i2OVqW o9s0 https://www.youtube.com/watch?v=8i2OVqW o9s0 Make a Magnetic Field https://www.youtube.com/watch?v=j8XNHlV6 Qxg https://www.youtube.com/watch?v=j8XNHlV6 Qxg Topic 6 Generators and Motors

17. Question: How are electricity and magnetism related? Topic 6 Generators and Motors

18. How are electricity and magnetism related? Electricity and magnetism related because flowing electrons produce a magnetic field. Electricity and magnetism are ALSO related because spinning magnets can produce electricity. Topic 6 Generators and Motors

19. Electricity and magnetism are related: flowing electrons produce a magnetic field spinning magnets can produce electricity https://www.youtube.com/watch?v=d_aTC0iK O68 https://www.youtube.com/watch?v=d_aTC0iK O68 Motor: – electricity -> mechanical energy Generator: – magnet -> mechanical force -> electricity Topic 6 Generators and Motors

20. Motor: – electricity -> mechanical energy Generator: – magnet -> mechanical force -> electricity

21. AC Generators - External force rotates the coil - Coil of wire rotates inside of a stationary magnetic field - Most generators use electromagnets instead of permanent magnets - As coil’s wires rotate inside the field, electrons move Topic 6 Generators and Motors

22. AC: Alternating Current AC generators produce electricity that changes directions After one half-rotation of the coil, each side passes near the opposite pole of the magnet, and the electrons move in the opposite direction Topic 6 Generators and Motors

23. Benefits of AC current Easy to increase/decrease the voltage This helps set up voltage for power line transmission (more in Topic 7) Topic 6 Generators and Motors

24. DC Generators Current in only one direction Topic 6 Generators and Motors

25. Electric Motors Convert electrical energy to mechanical energy Topic 6 Generators and Motors

26. Exploratory Stations Generator Motor Electromagnets Piezoelectric crystal Bar magnet’s field lines Topic 6 Generators and Motors