Electricity & Magnetism

1. Electricity & Magnetism

2. What is magnetism? Magnetism is the properties and interactions of magnets FYI: The earliest magnets were found naturally in the mineral magnetite which is abundant the rock-type lodestone. These magnets were used by the ancient peoples as compasses to guide sailing vessels. Magnets produce magnetic forces and have magnetic field lines

3. What is Magnetism? • Any material that attracts iron, steel, cobalt and nickel • Can be permanent or temporary

4. Magnetism Basics Only Certain Types of Materials Exhibit Magnetism N S • Magnets can be made in a variety of shapes, but all magnets have 2 poles • Opposite poles attract • North/South or Positive/Negative • Like poles repel All magnets have lines of force extending from one pole to the other in the 3 dimensional space around them

5. Magnetic Field Magnetic lines do not cross each other. The lines go from North to South on the magnet. Magnetic Lines of Flux N magnet S

6. N S N S Pulling Magnets Attracting Each Other

7. N S N S Pushing Apart Magnets Opposing Each Other

8. What are the characteristics of magnets? • North and south poles • “di”-poles • Break the magnet in half and you will have two separate magnets • 3 dimensional field of attraction

9. Where does magnetism come from? • Nature • Man-made materials from: • Ceramic • Alnico (aluminum, nickel, & cobalt) • Flexible rubber-like material • Created using current (electricity)

10. Uses for Magnets in Everyday Life • Cars • Power locks • Homes • Door bells • Microwaves • TV’s • Refrigerators • Speakers • Electricity • Schools • Whiteboards

11. Electricity Basics Electricity is….. • The flow of electrons • Things that are good conductors of electricity have lose electrons • Energy is sent out by batteries and generators (current electricity) • The shock you can get from rubbing your feet on the carpet (static electricity) • A bolt of lightning! (static electricity)

12. All Matter is Made up of Atoms MATTER (water, diamond) ELEMENTS (oxygen, carbon) O H H ATOMS (particles)

13. Atoms What is an Atom? • The smallest component in all things • Made up of three smaller particles • Protons (+) • Neutrons (no charge) • Electrons (-) • Strive for stability • Charged atom = ion

14. Particles with opposite charges attract each other. _ _ + + Opposites Attract Attraction

15. Static Electricity • The imbalance of positive and negative charges • Example: a build up of negative charges in a storm cloud will travel to the ground in the form of lightening

16. + - + + - + - - + + - + + - - + - - Static Electricity • Start with a doorknob – no charge • Walk along carpet: strip electrons from carpet that collect in your body… You become negatively charged • Approach the doorknob and the positive charges move toward you. Negative charges move away. - - - - - - -

17. + - - + - + - + + - - + - - - - Static Electricity • When close enough, the electrons will jump toward the positive doorknob and ZAP! You’ve been shocked by static electricity. - - - - - - -

18. + - + - - + - - - - Static Electricity • When close enough, the electrons will jump toward the positive doorknob and ZAP! You’ve been shocked by static electricity. • Now you and the doorknob have the same charge. + + + +

19. Current Electricity • Electric current is the movement of free electrons from atom to atom • To start the free electrons moving an electromotive force is needed. • Generator • Batteries

20. References • www.srpnet.com • www.ieee.org • www.coolmagnetman.com/magreview.htm • www.en.wikipedia.org/wiki/Magnets • www.creativekidsathome.com/science/magnetexp.html • www.howstuffworks.com • www.eia.doe.gov/kids/glossary