4 th Grade Science Unit A: Physical Sciences Chapter 1: Electricity Lesson 1: How do charged objects behave?

Transcription

1 4 th Grade Science Unit A: Physical Sciences Chapter 1: Electricity Lesson 1: How do charged objects behave?

2 electric charge

3 An electric charge is a property of some part of matter, described as positive or negative.

4 Atoms are made of even small particles. Some of these particles have electric charge. Oral Response Task What is an electric charge?

5 neutral

6 Neutral means neither positive or negative.

7 The matter has no charge. It is neutral. Oral Response Task Restate the definition of neutral.

8 attract

9 To attract means to be pulled toward each other.

10 Objects wit unlike charges are pulled toward, or attract, each other. Oral Response Task Explain what it means to attract.

11 repel

12 To repel means to be pulled away from each other.

13 Objects with like charges are pushed away from, or repel, each other. Oral Response Task Explain what it means to repel.

14 electron

15 An electron is the part of an atom with a negative charge.

16 When objects are near each other, electrons can move from one object to another. Oral Response Task Describe an electron.

17 static electricity

18 Static electricity is the build-up of positive or negative charges.

19 Ice and water droplets inside clouds rub against each other. Positive charges build up near the top clouds, and negative charges build up near the bottom clouds. In time, the static electrical energy is released. Oral Response Task Explain static electricity.

20 4 th Grade Science Unit A: Physical Sciences Chapter 1: Electricity Lesson 2: How do electric charges move?

21 electric current

22 Electric current is electric charges in motion.

23 Batteries can cause electricity to flow. Other devices change electric current into other forms of energy. Oral Response Task Discuss the definition of an electric current.

24 circuits

25 Electric circuits are the paths of currents that have controlled direction and flow.

26 If the direction and flow of current are controlled, the path that the current flows is called an electrical circuit. Oral Response Task Describe electric circuits.

27 conductors

28 Conductors are materials that have low resistance and allow electricity to flow easily.

29 The switches, wires, and clips are conductors. Many conductors are made of metal. Oral Response Task Explain the definition of a conductor.

30 resistance

31 Resistance is a property of material that does not allow electric current to flow easily through it.

32 The thin coiled wire inside the bulb is a resistor. Oral Response Task Differentiate between resistor and a conductor.

33 series circuit

34 A series circuit is a circuit in which electric charge can flow only in one path.

35 A series circuit can have more than one resistor. Oral Response Task Restate the definition of a series circuit.

36 4 th Grade Science Unit A: Physical Sciences Chapter 1: Electricity Lesson 3: What are parallel circuits?

37 parallel circuits

38 Parallel circuits are circuits with two or more path through which electric current can flow.

39 Parallel circuits are circuits that have more than one branch. The current can be switched in one branch and still flow through the other branches. Oral Response Task Describe parallel circuits.

40 short circuit

41 A short circuit occurs when electric current that follows a path other than the path meant for it to flow.

42 Short circuits often happen when a frayed or damaged wire touches a good conductor, such as metal or water. Oral Response Task Hypothesize what could happen if there were a short circuit.

43 4 th Grade Science Unit A: Physical Sciences Chapter 2: Magnetism Lesson 1: What are magnetic fields?

44 magnetism

45 Magnetism is a force that acts on either a moving electric charge or a material that is near a magnet.

46 Magnetism is a pulling or pushing force caused by the motion of electric charges. Oral Response Task Describe magnetism.

47 magnetic field

48 A magnetic field is the space around a magnet in which magnetic forces operate.

49 Magnetic fields are invisible, but you can detect their shapes by using iron filings. Oral Response Task Analyze the characteristics of a magnetic field.

50 magnetic poles

51 Magnetic poles are the two ends of a magnet, called the north magnetic pole and the south magnetic pole.

52 The magnetic field is stronger in the magnetic poles. The north and south magnetic poles are pulled to the north and south by the Earth s magnetic field. Oral Response Task Differentiate between the magnetic poles.

53 force

54 Force is strength or power exerted upon an object.

55 A magnetic field is the space around a magnet in which magnetic forces operate. Oral Response Task Describe a force.

56 iron filings

57 Iron filings are small particles of iron.

58 Iron filings show the magnetic field around each magnet. Oral Response Task Define iron filings.

59 magnet

60 A magnet is something that attracts iron and certain other metals.

61 A U shaped magnet has two poles. If it is broken, the pieces are not longer U-shaped. But each piece still has a north and south pole. Oral Response Task Describe a magnet.

62 4 th Grade Science Unit A: Physical Sciences Chapter 2: Magnetism Lesson 2: What are magnetic effects?

63 compass

64 A compass is an instrument that has a magnetic needle that point to the north.

65 Wherever you are on Earth, one end of a compass needle will point toward Earth s magnetic north pole. Oral Response Task Restate the definition of a compass.

66 magnetite

67 Magnetite is a black magnetic mineral, found in igneous and metamorphic rocks that is strongly attracted by magnets.

68 Magnetite is a rock that pulls the compass needle away from the north. Oral Response Task Describe the properties of a magnetite rock.

69 4 th Grade Science Unit A: Physical Sciences Chapter 2: Magnetism Lesson 3: How are electric currents and magnetic fields related?

70 electromagnet

71 An electromagnet is a coil of wire through which electric current passes, creating a magnetic field.

72 The strength of a electromagnet can be changed by putting an iron or steel bar inside the coil or wire. Oral Response Task Discuss how an electromagnet works.

73 4 th Grade Science Unit A: Physical Sciences Chapter 2: Magnetism Lesson 4: How are electromagnets used?

74 transformer

75 A transformer is an electric device that uses an electric magnet to transform electric energy.

76 A transformer controls the amount of current that is sent to the electromagnet. Oral Response Task Describe a transformer.

77 motion

78 Motion is the change in the position of an object over time.

79 Mechanical energy is the energy involved in motion. Oral Response Task Describe motion.

80 generator

81 A generator is a machine that uses moving magnets to produce electrical energy.

82 Huge generators provide the electric power for most homes, buildings, and factories. Oral Response Task Restate the purpose of a generator.