1. Electricity and Magnetism

2. Atom Review Electrons have a negative charge (-) Protons have a positive charge (+)

3. Like charges repel each other Unlike charges attract each other

5. electric field: the field around charged particles that exert force on other charged particles

6. A charged particle in the electric field of another particle will either be pushed or pulled, depending on the charge.

7. Static Charge Protons are bound tightly in the nucleus of an atom, but electrons can sometimes leave the atom

8. Insulator: a material through which charges of an electrical current are not able to move Ex. wood, rubber, glass

9. Conductor: A material through which electrons can move freely Ex. copper, gold, aluminum

10. If an object loses electrons, then it has an overall positive charge. If an object gains electrons, then it has an overall negative charge.

12. static electricity: the buildup of charges on an object Van de Graaf generator: produces static electricity

13. Charges can be transferred to one another in three ways: 1. friction 2. conduction 3. induction

14. Friction: transfer of electrons by rubbing

15. Conduction: transfer of electrons from one object to another by direct contact

16. Induction: movement of electrons to one part of an object caused by the electric field of another object

17. Law of Conservation of Charge: Charges cannot be created or destroyed. Electrons can only be transferred from one object to another.

18. Examples of static electricity: Static cling in the dryer Plastic wrap

19. When a negatively charged object and a positively charged object come together, the electrons move until the charges balance out

20. static discharge: the loss of static electricity as electrons move off an object - this can also be called GROUNDING

21. Examples of static discharge: shock from walking across a carpet and touching something made of metal lightning

23. - It is always better to err on the side of caution – if you see lightning and you are outside – GET INSIDE - Always turn off electricity at the circuit breaker before attempting home repairs Electrical Safety

24. - the 3 rd prong found in most electrical outlets is for the “ground” wire; it provides a path for electricity to reach the ground in case of a surge (it helps to protect both the equipment and helps to prevent electrical fires within the walls of your home) - Under NO circumstances should you EVER remove the 3 rd prong of a cord to fit a plug into a 2 prong outlet

25. Electrical Circuits

26. electrical potential: the potential energy per unit of electrical charge

27. voltage: the difference in the amount of electrical potential between 2 objects

28. - measured in volts (V) voltmeter: device used to measure voltage

29. Electrons will flow as long there is a difference in the electrical potential Voltage causes current to flow through an electrical circuit

30. electrical circuit: a complete path through which electrical charges can flow

31. voltage source: creates a potential energy difference in an electrical circuit ex. batteries and generators

32. current (I): the flow of electric charges through a material measured in Amperes (A) ammeter: device used to measure current

33. resistance: the opposition to the movement of electric charges through a material measured in Ohms (  )

34. - depends on the thickness and length of a wire, as well as how well the material conducts electricity

35. resistor: a device in electrical circuits that uses electrical energy as it interferes with the flow of electric charge

36. The greater the resistance, the less current there is for a given voltage

37. If an electrical current can travel through one of two paths, it will choose the “path of least resistance”

39. Inside an XBox 360

40. Ohm’s Law Resistance = Voltage Current

41. OR V IR

42. Types of Circuits: Series & Parallel

43. Series Circuit: a circuit where there is only one path for the current to take - all parts of the circuit are connected one after another

44. A series circuit

45. ex. Xmas tree lights - if one bulb burns out, the whole strand goes out because there is no other path for the current to take

46. When more resistors, (ex. light bulbs) are added to the circuit, the light becomes dimmer.

47. Remember! If resistance increases, then current decreases. Therefore, the bulbs will burn less brightly.

48. Parallel Circuit: a circuit that has several paths for the current to take - different parts of the circuit are on separate branches

49. A parallel circuit

50. If one bulb burns out, the rest of the lights stay on because the current can move through the other branches.

51. As additional resistors are added, the brightness of the light does not change

52. Electromagnetism

53. magnetism: the attraction of a magnet for another object magnetic pole: the area of a magnet where the magnetic effect is the strongest

54. Poles that are alike repel each other, poles that are unlike attract each other.

55. magnetic field: region of magnetic force around a magnet

56. magnetic domain: a cluster of billions of atoms that all have magnetic fields that are lined up in the same way

57. In a magnetized material, all or most of the domains are arranged in the same direction That means that all the domains are aligned!

58. Magnets can lose their magnetic properties by being dropped, struck hard or heated. (the domains are knocked out of alignment)

59. When a magnet is broken in half, it does NOT lose its magnetism, it simply becomes 2 magnets!

60. An electric current produces a magnetic field.

61. solenoid: a current carrying coil of wire with many loops - creates a magnetic field that can be turned on and off

62. electromagnet: a strong magnet that can be turned on and off

63. Examples of electromagnets: - solenoid - junkyard crane - tape recorder

64. Generating Electricity An electric current will be produced in a conductor when the conductor moves across the lines of a magnetic field.

65. electromagnetic induction: the process of generating an electric current from the motion of a conductor through a magnetic field

66. The flow of an induced current may be constant or may change direction

67. alternating current (AC): a current consisting of charges that move back and forth in a circuit ex. the circuits in your home

68. direct current (DC): current consisting of charges that flow in one direction ex. battery