This document summarizes a general science unit on electricity and magnetism. It covers topics including the properties of magnets, how magnetic poles interact, magnetic fields, electromagnets, generators, motors, and transformers. Key points are that electric currents create magnetic fields, and magnetic fields can induce electric currents. Motors convert electrical energy to mechanical motion using these principles, while generators operate in reverse to produce electricity from mechanical inputs. Transformers are used to increase or decrease voltage in electrical systems. Students will have a chapter test on these concepts on Wednesday.

1. General Science Unit 3:
Electricity and Magnetism
Chapter 7

2. 7.1 Standards
and
Objectives
Identify and describe the properties of magnets.
• 6.S.1A.3
• 6.S.1B.1
Identify
and
describe
Explain how magnetic poles interact.
• 6.S.1A.3
Explain
Develop and use models to exemplify how magnetic fields
produced by electrical energy flow in a circuit is interrelated in
electromagnets, generators, and simple electrical motors.
• 6.P.3A.4
Develop
and use

3. 7.1 Untamed Science Video
Magnetism: What’s the Attraction?
https://classroom.google.com/c/ODU5NjI2NzA2MFpa/a/NTc3MjYwOD
ExMlpa/details

4. 7.1 What is Magnetism?
In short, magnetism is the attraction or repulsion
of magnetic materials.
Any material that attracts iron and materials that
contain iron is considered a magnet.

8. Magnetic Pole Interaction
https://youtu.be/Mp0Bu75MSj8
https://youtu.be/xuO6okkyJ7c

10. Questions to consider
• What are some properties of magnets?
• Contain iron
• Has two poles
• Is attracted to other objects that contain iron.
• How do magnetic poles interact?
• If poles are the same, they repel
• If poles are different, they attract
• Magnetic pole interactions cause a magnetic field

11. 7.2 Standards and Objectives
Describe a
magnetic field.
6.S.1A.2
6.S.1A.3
6.S.1A.6
Describe Earth’s
magnetic field.
6.S.1A.2
6.S.1A.4

12. Magnetic Field
Lines
• https://youtu.be/00lqFyQI8CM
https://youtu.be/V-M07N4a6-Y

13. Page 272 What is Earth’s magnetic field like?
• Earth has two poles and a magnetic field around just like a bar
magnet.
• The magnetic field is generated from circulation of the liquid iron
core.
• The magnetic field is similar to that of a bar magnet.

14. Magnetic declination
• In layman’s terms, it is the difference between the location of the
physical north pole and the magnetic north pole of the earth.

18. 7.3 Standards
and
Objectives
Explain how electric current is related to magnetism.
•6.S.1A.3
•6.P.3A.4Explain
Identify some characteristics of a magnetic field produced by a current.
•6.P.3A.4
•6.S.1A.2
•6.S.1A.6
Identify
Describe the characteristics of solenoids and electromagnets.
•6.P.3A.4
•6.S.1A.2
•6.S.1A.6
Describe

19. Things to ponder…
• How are electric currents and magnetic fields related?
• What is a magnetic field produced by a current like?
• What are the characteristics of solenoids and
electromagnets?

20. Hans Christian Oersted
• In 1820, he accidentally discovered that a magnetic field
could be produced by an electric current.
• He was a professor at the University of Copenhagen

21. Oersted's
Experiment
• https://youtu.be/RwilgsQ9xaM

22. Compass Deflection Page 275
• From the video, what happened to the compasses when the electric
current was removed?
• What about when the electric current was on?
• Explain the movement of the compass needles during the
experiment.

24. What is a magnetic field produced by a
current is like?
The magnetic field produced by a current has a strength and
direction. The field can be turned on and off, have it’s
direction reversed, or have its strength changed.
Page 277

28. Oersted’s Experiment
• What did Oersted conclude?
He concluded that an electric current does create a magnetic field
around the wire and in the direction of the current flow.

29. How does a current affect a compass?
The moving current deflects the compass needle based on its direction
of flow.

31. How do we change the strength of an
electromagnet?
• Increase the electric current
• Increase the number of turns in the wire carrying the electric current.
Page 277

32. Poles of a solenoid
• How do we change the magnetic poles of a solenoid?
We change the magnetic poles by changing the direction of current
flow.
Page 278

33. 7.4 Standards and Objectives
• 6.P.3A.4
• Explain how electrical energy can be transformed into mechanical
energy.
• Describe how galvanometers work.
• Describe how electric motors work.

34. How is electrical energy transformed into
mechanical energy?
• Electrical energy is transformed into mechanical energy through
devices called electric motors.
• Electric motors work on the principle of when a wire with a current is
placed in a magnetic field, electrical energy is transformed into
mechanical energy.
• Electric Motor Animation https://youtu.be/Xi7o8cMPI0E
Page 281

35. Electric Motors
• They operate by rotating a wire with an electric current within a
permanent magnetic field.
• The wire generates a magnetic field that tries to align with the
magnetic poles of the permanent magnet.
• A small switch called a commutator turns the current on and off
preventing the alignment of the magnetic field with the permanent
magnetic poles.
Page 284

36. Electric motor detailed operation
• https://youtu.be/wxG3cwugXgs

37. Galvanometer? What is this?
• Galvanometers are devices that measure small currents.
• They can be found in instruments like
• Automotive fuel gauges
• Volt meters
• Car speedometer
Page 282

38. Galvanometer operation principle
• Galvanometers operate on the principle of a suspended
electromagnet coil placed between opposite poles of a permanent
magnet.
• When a current is run into the electromagnetic coil, the magnetic
field created attempts to align with the poles of the permanent
magnet.
• The coil has a pointer attached, which is used to indicate a specific
purpose. (Amount of current going to the car’s battery)
Page 282

39. Galvanometer animation
• https://youtu.be/CqW5rmmqv_Y

40. 7.5 Standards and Objectives
• 6.P.3A.4
• Explain how an electric current can be produced in a conductor.
• Describe how a generator works.
• Describe what a transformer does.
• Describe the similarities of motors and generators.

41. Electric current induction
• If a wire coil is moved through a magnetic field, a electric current is
generated within the wire.
• If a permanent magnet is moved through a wire coil, an electric
current is generated within the wire.
• Page 284, 288

42. Two types of electric current
• Direct Current (DC)
• The charges of the current flow in one direction.
• The charges move from one end of a battery to the other end.
• Alternating Current (AC)
• The charges in the current rapidly change directions
• This current if generated by either moving the coil or the magnet up and
down repeatedly.
• The major advantage of AC over DC is that AC voltage can be easily raised or
lowered.
• Page 289

43. Generators
• Generators function by rotating a coil of wire within a magnetic field
to produce a current.
• Generators use motion (mechanical energy) in a magnetic field to
produce current.
• They can be:
• Hand driven
• Water driven
• Wind powered
Page 290

44. Transformers
• Transformers are devices that increase or decrease voltage.
• They are found on light poles, in cell phones, on electric power
cables, etc.
• There are two types:
• Step up
• Step down
• Page 292

45. Step up transformer

46. Step down transformer

47. Ratio
• The ratio of the number of turns on the primary winding side to the
secondary winding side determines what happens to the current.
• Primary winding = 5 turns
• Secondary winding = 10 turns
The result is a doubling of the electric current voltage.
10 ÷ 5 = 2

48. Chapter test on Wednesday
Take textbooks and notes home to study.
Bonus points on the test will be added through a random process.
20 Multiple Choice Questions