1. Magnetism, Electricity & Electromagnetism
Ms. Mannix
2016 Honors Physical Science
DFA

2. Magnetic Fields - What Is Magnetism?
Magnetic field lines spread out from one pole, curve around the magnet, and return to the other pole.

3. Magnetic Fields - What Is Magnetism?
When the magnetic fields of two or more magnets overlap, the result is a combined field.

4. Magnetic Field Lines Activity
- What Is Magnetism?
Magnetic Field Lines Activity
Click the Active Art button to open a browser window and access Active Art about magnetic field lines.

5. The Atom - Inside a Magnet
An atom contains neutrons and positively charged protons in its nucleus. Negatively charged electrons move randomly throughout an atom.

6. Magnetic Domains - Inside a Magnet
In a magnetized material, all or most of the magnet domains are arranged in the same direction.

7. Magnetic Domains - Inside a Magnet
Modern magnets come in a variety of shapes and are made from many different materials.

8. Making and Changing Magnets
- Inside a Magnet
Making and Changing Magnets
Each piece of a magnet retains its magnetic properties after it is cut in half.

9. Earth as a Magnet - Magnetic Earth
Just like a bar magnet, Earth has a magnetic field surrounding it and two magnetic poles.

10. Movement of Earth’s Magnetic Poles
- Magnetic Earth
Movement of Earth’s Magnetic Poles
Earth’s magnetic poles move slowly over time. The data in the table show the position of Earth’s magnetic north pole in specific years.

11. Movement of Earth’s Magnetic Poles
- Magnetic Earth
Movement of Earth’s Magnetic Poles
Interpreting Data:
What is the trend in the speed of the pole’s movement?
The average speed of the pole’s movement is increasing.

12. Movement of Earth’s Magnetic Poles
- Magnetic Earth
Movement of Earth’s Magnetic Poles
Calculating:
What is the total distance the pole has traveled over the time shown?
Between 1948 and 2001, the pole has moved 857 km (150 km km +120 km km km).

13. Movement of Earth’s Magnetic Poles
- Magnetic Earth
Movement of Earth’s Magnetic Poles
Predicting:
Using the data, predict the average speed of the pole’s movement between 2001 and Explain.
The average speed increased by 23 km/yr from 1994 to That is an increase of 3.3 km/yr per year. There are 9 years between 2001 and Therefore, a good prediction is that the average speed in 2010 will be 29.7 km/yr.

14. The Magnetosphere - Magnetic Earth
The solar wind causes Earth’s magnetic field to stretch out on the side of Earth not facing the sun.

15. Electricity

16. Electric Charge - Electric Charge and Static Electricity
Charges that are the same repel each other. Charges that are different attract each other.

17. Electric Force - Electric Charge and Static Electricity
An electric field is a region around a charged object where the object’s electric force is exerted on other charged objects.

18. Electric Force - Electric Charge and Static Electricity
An electric field is a region around a charged object where the object’s electric force is exerted on other charged objects.

19. Transferring Charge - Electric Charge and Static Electricity
There are three methods by which charges can be transferred to build up static electricity: charging by friction, by conduction, and by induction.

20. Transferring Charge - Electric Charge and Static Electricity
An electroscope can be used to detect the presence of a charge.

21. Flow of Electric Charges
- Electric Current
Flow of Electric Charges
Electric current is the continuous flow of electric charges through a material.

22. An Electric Circuit - Electric Current
An electric circuit is a complete, unbroken path through which electric charges can flow.

23. Resistance - Electric Current
Two factors that affect the resistance of water flowing in a pipe are diameter and length. The diameter and length of a wire also affect resistance in a circuit.

24. The First Battery - Batteries
Volta built the first electric battery by layering zinc, paper soaked in salt water, and silver.

25. Electrochemical Cells
- Batteries
Electrochemical Cells
An electrochemical cell is a device that transforms chemical energy into electrical energy.

26. Electrochemical Cells
- Batteries
Electrochemical Cells
An electrochemical cell in which the electrolyte is a liquid is a wet cell.

27. Electrochemical Cells
- Batteries
Electrochemical Cells
A dry cell is an electrochemical cell in which the electrolyte is a paste.

28. Features of a Circuit - Electric Circuits
Simple symbols are used to diagram a circuit.

29. Series Circuits - Electric Circuits
In a series circuit, there is only one path for the current to take.

30. Parallel Circuits - Electric Circuits
In a parallel circuit, there are several paths for the current to take.

31. Decimals - Electric Circuits
When calculating voltage, you often use decimals. When you multiply two decimals, the number of decimal places in the product is the sum of the number of decimal places in each decimal you multiply.
If a circuit has a resistance of 30.5 ohms and a current of 0.05 amps, what is its voltage?

32. Decimals - Electric Circuits Practice Problem
Use Ohm’s law to calculate the voltage of a circuit with a resistance of 15.2 ohms and a current of 0.10 amps.
1.52 volts

33. Calculating Resistance
- Electric Circuits
Calculating Resistance
The brake light on an automobile is connected to a 12-volt battery. If the resulting current is 0.40 amps, what is the resistance of the brake light?
Read and Understand
What information are you given?
Battery Voltage = 12 V
Current = 0.40 A

34. Calculating Resistance
- Electric Circuits
Calculating Resistance
The brake light on an automobile is connected to a 12 volt battery. If the resulting current is 0.40 amps, what is the resistance of the break light?
Plan and Solve
What quantity are you trying to calculate?
The resistance of the brake light
What formula contains the given quantities and the unknown quantity?
Resistance = Voltage/Current
Perform the calculation.
Resistance = 12 V/0.40 A = 30 Ω

35. Calculating Resistance
- Electric Circuits
Calculating Resistance
The brake light on an automobile is connected to a 12-volt battery. If the resulting current is 0.40 amps, what is the resistance of the brake light?
Look Back and Check
Does your answer make sense?
The answer makes sense because you are dividing the voltage by a decimal. The answer should be greater than either number in the fraction, which it is.

36. Calculating Resistance
- Electric Circuits
Calculating Resistance
Practice Problem
In a circuit, there is a 0.5-A current in the bulb. The voltage across the bulb is 4.0 V. What is the bulb’s resistance?
8.0 Ω (4.0 V ÷ 0.5 A)

37. Calculating Resistance
- Electric Circuits
Calculating Resistance
Practice Problem
A waffle iron has a 12-A current. If the resistance of the coils is 10 Ω, what must the voltage be?
120 V (12 A X 10 Ω)

38. Electric Power - Electric Power
The rate at which energy is transformed from one form to another is known as power. Power is measured in watts (W).

39. Calculating Power - Electric Power
A household light bulb has about 0.5 amps of current in it. Since the standard household voltage is 120 volts, what is the power rating for this bulb?
Read and Understand
What information have you been given?
Current = 0.5 A
Voltage = 120 V

40. Calculating Power - Electric Power
A household light bulb has about 0.5 amps of current in it. Since the standard household voltage is 120 volts, what is the power rating for this bulb?
Plan and Solve
What quantity are you trying to calculate?
The power of the light bulb = ?
What formula contains the given quantities and the unknown quantity?
Power = Voltage X Current
Perform the calculation.
Power = 120 V X 0.5 A
Power = 60 W

41. Calculating Power - Electric Power
A household light bulb has about 0.5 amps of current in it. Since the standard household voltage is 120 volts, what is the power rating for this bulb?
Look Back and Check
Does your answer make sense?
The answer is reasonable, because 60 W is a common rating for household light bulbs.

42. Calculating Power Practice Problem - Electric Power
A flashlight bulb uses two 1.5-V batteries in series to create a current of 0.5 A. What is the power rating of the bulb?
1.5 W (3.0 V X 0.5 A)

43. Calculating Power Practice Problem - Electric Power
A hair dryer has a power rating of 1,200 W and uses a standard voltage of 120 V. What is the current through the hair dryer?
10 A (1,200 W ÷ 120 V)

44. Calculating Electrical Energy
E=Pt

45. Electrical Equipment and Fires
- Electrical Safety
Electrical Equipment and Fires
If electrical equipment is not properly used and maintained, it can cause fires. The circle graph shows the percentage of fires caused by different types of electrical equipment.

46. Electrical Equipment and Fires
- Electrical Safety
Electrical Equipment and Fires
Reading Graphs:
What determines the size of each wedge in the graph?
The percentage of fires caused by a certain type of electrical equipment

47. Electrical Equipment and Fires
- Electrical Safety
Electrical Equipment and Fires
Reading Graphs:
What percentage of fires are caused by appliances?
15%

48. Electrical Equipment and Fires
- Electrical Safety
Electrical Equipment and Fires
Interpreting Data:
Which category of equipment is responsible for the most fires? Which category is responsible for the fewest fires?
Cooking equipment is responsible for the most fires. Heating and cooling equipment is responsible for the fewest fires.

49. Grounding - Electrical Safety
One way to protect people from electric shock and other electrical danger is to provide an alternate path for electric current.

50. Breaking a Circuit - Electrical Safety
In order to prevent circuits from overheating, devices called fuses and circuit breakers are added to circuits.

51. Graphic Organizer Devices to prevent circuits from overheating
include
Circuit breakers
Fuses
work by
work by
Bending away from wires
Melting

52. Electric Current and Magnetism
- What Is Electromagnetism?
Electric Current and Magnetism
An electric current produces a magnetic field.

53. Solenoids - What Is Electromagnetism?
The magnetic field produced by a current has three distinct characteristics. The field can be turned on or off, have its direction reversed, or have its strength changed.
A solenoid is a type of electromagnet when the purpose is to generate a controlled magnetic field.

54. Solenoids - What Is Electromagnetism?
The magnetic field around a solenoid resembles that of a bar magnet.

55. Electromagnets - What Is Electromagnetism?
A doorbell rings as the magnetic field of an electromagnet turns on and off.

56. Electromagnets - What Is Electromagnetism?
Electromagnets are used to lift heavy objects. A switch is turned on in the crane so that a current is produced in the electromagnet.

57. Electrical Energy and Motion
Electricity, Magnetism,
and Motion
Electrical Energy and Motion
When a wire with current is placed in a magnetic field, electrical energy is transformed into mechanical energy.

58. Galvanometers Electricity, Magnetism, and Motion
An electric current is used to turn the pointer of a galvanometer.

59. Electric Motors Electricity, Magnetism, and Motion
An electric motor transforms electrical energy into mechanical energy.

60. Induction of Electric Current
- Electricity From Magnetism
Induction of Electric Current
An electric current is induced in a conductor when the conductor moves through a magnetic field.

61. Induction of Electric Current
- Electricity From Magnetism
Induction of Electric Current
If a magnet moves through a coil of wire, a current is induced in the wire.

62. Generators - Electricity From Magnetism
A generator uses motion in a magnetic field to produce an electric current.

63. Generators - Electricity From Magnetism
In most generators, a source of mechanical energy turns huge turbines such as this one. The turbine is attached to the armature of a generator, which produces current.

64. Compare and Contrast

65. Transformers - Electricity From Magnetism
A transformer is a device that increases or decreases voltage.

66. Types of Transformers - Electricity From Magnetism
Voltage can be changed depending on the number of loops in the primary and secondary coils.