1. “What is Electricity?” Review
Atomic Structure
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
“What is Electricity?” Review

2. Atomic Structure What is an Element? Atomic Structure
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Atomic Structure
What is an Element?

3. Elements The simplest form of matter Atomic Structure
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Elements
The simplest form of matter
Matter is the material from which all known physical objects are made.
The image is of Beryllium, which has an atomic number of 4.

4. What is an Atom?

5. Atomic Structure
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Atoms
The smallest piece of an element that contains all properties of that element

6. What 3 particles make up atoms?

7. Components of an Atom Electrons Negatively charged atomic particles
Atomic Structure
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Components of an Atom
Electrons
Negatively charged atomic particles
Protons
Positively charged atomic particles
Neutrons
Uncharged atomic particles

8. What determines the atomic number of an atom?
What is the atomic number of Copper (Cu)?

9. Atomic Number How many protons are in this nucleus?
Atomic Structure
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Atomic Number
The atomic number is equal to the number of protons in the nucleus of an atom.
The atomic number identifies the element.
How many protons are in this nucleus?

10. Periodic Table of Elements
Atomic Structure
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Periodic Table of Elements
NASA
Which element has 4 protons?

11. For this unit, we mainly care about electrons in atoms.
Atomic Structure
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Electrons
For this unit, we mainly care about electrons in atoms.
Why?
It is important to understand the “how and why” of the movement of electrons to understand electricity.

12. Draw a representation of a Sulfur atom (Atomic Number 16).
Draw a representation of a Helium atom (Atomic Number 2)
Filling order:
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, …

13. Atomic Structure
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Electron Orbits
Atoms like to have their valence level either filled (8) or empty(0) of electrons.
How many electrons are in the valence level? 6
Sulfur has space to gain two electrons in its valence level.
It is easier for the sulfur atom to pick up 2 electrons to be full, than to get rid of 6 electrons to be empty.

14. What is a valence electron?
How many valence electrons do conductors have?
How many valence electrons do insulators have?
How about semiconductors?

15. Conductors and Insulators
Electricity
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Conductors and Insulators
Conductors
Insulators
Electrons flow easily between atoms
1-3 valence electrons in outer orbit
Low Electronegativity
Good Conductors: Silver, Copper, Gold, Aluminum . . .
Electron flow is difficult between atoms
5-8 valence electrons in outer orbit
High Electronegativity
Examples: Mica, Glass, Rubber, Plastic . . .
Many examples of insulators are materials because atoms of one element have already bonded with atoms from other elements to make the materials very stable.

16. Using a Multimeter
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity
What is a Multimeter?
An instrument for measuring the properties of an electrical circuit
Sometimes the multimeter is referred to as the “Swiss Army knife” of electricity.
Common measurements include continuity, voltage, current, and resistance. These are further discussed in this presentation and other presentations in this lesson.
Point out that the third multimeter is analog and the other three are digital. Which would be more accurate?

17. Manual vs. Auto Ranging 6 volts 50 millivolts 800 millivolts 800 volts
Using a Multimeter
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity
Manual vs. Auto Ranging
Where should you set the meter if you expect a reading around . . .
1000 volts
6 volts
50 millivolts
800 millivolts
800 volts
125 volts
200 volts
20 volts
2000 millivolts
The example given is for volts, but setting choices include current and resistance.
200 millivolts

18. . . .opposite charges attract and like charges repel.
Electricity
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
History
. . .opposite charges attract and like charges repel.
Ben Franklin suggested that . . . + -

19. . . .opposite charges attract and like charges repel.
Electricity
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
History
. . .opposite charges attract and like charges repel.
Ben Franklin suggested that . . .
The Law of Charges explains why the electrons continue to be bonded to the nucleus.
The law of charges was first discovered by Charles Augustin de Coulomb. It explains that all magnetic objects have the tendency to repel or attract to one another. Like charges repel one another and unlike charges attract one another. The attraction or repulsion occurs in a straight line, there is a force between the charges and the bigger the charges the greater the force. + +

20. Electricity
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Electron Flow
An electron from one atom can knock out an electron from another atom.

21. Electricity
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Electron Flow
Electricity is created as electrons collide and transfer from atom to atom.
Play Animation

22. What Makes Up Electricity?
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
What Makes Up Electricity?
Let’s compare it to something we know --- Water!

23. Water Analogy Tank = Battery Pipe = Wiring Faucet = Switch Tank Faucet
Presentation Name
Gateway To Technology®
Unit # – Lesson #.# – Lesson Name
Water Analogy
Tank
Faucet
Pipe
It might be necessary to remind students what an analogy is.
Tank = Battery
Pipe = Wiring
Faucet = Switch

24. What is current?

25. Current Current: The flow of electric charge Tank (Battery)
Presentation Name
Gateway To Technology®
Unit # – Lesson #.# – Lesson Name
Current
Current: The flow of electric charge
Tank (Battery)
Faucet (Switch)
Pipe (Wiring)
It might be necessary to remind students what an analogy is.
When the faucet (switch) is off, is there any flow (current)? NO
When the faucet (switch) is on, is there any flow (current)?
YES

26. Current in a Circuit When the switch is off, there is no current.
Presentation Name
Gateway To Technology®
Unit # – Lesson #.# – Lesson Name
Current in a Circuit
off on
off on
When the switch is off, there is no current.
When the switch is on, there is current.

27. What is voltage?

28. Voltage Voltage: The force (pressure) behind the flow of current
Presentation Name
Gateway To Technology®
Unit # – Lesson #.# – Lesson Name
Voltage
Voltage: The force (pressure) behind the flow of current
Tank (Battery)
Faucet (Switch)
Pipe (Wiring)
When the faucet (switch) is off, is there any pressure (voltage)?
YES – Pressure (voltage) is pushing against the pipe, tank, and the faucet.
When the faucet (switch) is on, is there any pressure (voltage)?
YES – Pressure (voltage) pushes flow (current) through the system.

29. Presentation Name
Gateway To Technology®
Unit # – Lesson #.# – Lesson Name
Voltage in a Circuit
off on
off on
The battery provides voltage that will push current through the bulb when the switch is on.

30. What is resistance?

31. Resistance Resistance: The opposition to the flow of current.
Presentation Name
Gateway To Technology®
Unit # – Lesson #.# – Lesson Name
Resistance
Resistance: The opposition to the flow of current.
Tank (Battery)
Faucet (Switch)
Pipe (Wiring)
All materials have resistance. Conductors have little resistance. Insulators provide a lot of resistance. Some electronic components (resistors) have a specific resistance. These are often needed to reduce current in order to protect other components or to adjust the amount of current that goes to other components.
What happens to the flow (current) if a rock gets lodged in the pipe?
Flow (current) decreases.

32. Resistance in a Circuit
Presentation Name
Gateway To Technology®
Unit # – Lesson #.# – Lesson Name
Resistance in a Circuit
Resistor
off on
Resistors are components that limit the flow of electricity.
Reducing current causes the bulb to become more dim.

33. What types of electricity are there?33

34. Types of Electricity Static Electricity Current Electricity
The electrical charge an object develops as a result of having an unequal number of protons and electrons.
(Static Electricity) When the imbalance of charge becomes too great, the electrons will move.
(Current Electricity) The movement happens when a push (voltage) is applied to the electrons.
Current Electricity
The movement of electrons through a conductor. 34

35. Static Electricity Uncontrollable Electricity Lightening Static Cling
Wool socks on a carpet “shocks” 35

36. What are the two types of current electricity?
What is the difference between these two?

37. Alternating Current (AC)
Current Electricity
Two Types:
Direct Current (DC)
Alternating Current (AC) 37

38. Direct Current
The electrons flow in the same direction all the time, from negative to positive. 38

39. Direct Current Comes from Batteries Converted from Alternating Current
Used for electronic devices including
Computers
iPods
Cell phones
Anything that has a “charger”
Batteries provide current electricity through a chemical reaction. In today’s activity students will “build” a DC battery.
Anything that has a cord with a “box” attached to the cord is converting AC current to DC current.
Show examples of cords with converter boxes.
Demonstrate using the multimeter to measure the voltage of the battery. Show how switching the leads from the multimeter on the battery changes the + or - sign in the display. This happens because DC voltage is directional. Black lead to negative and red lead to positive will show a positive voltage. Black lead to positive and red lead to negative will give a negative voltage. (This will help students answer the Conclusion question #2 in the next activity.) 39

40. The electrical current (movement of electrons) changes direction.
Electricity
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
Alternating Current
The electrical current (movement of electrons) changes direction.

41. Alternating Current Comes from Generators
Electricity
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
Alternating Current
Comes from Generators
Coal burning and nuclear power plants
Hydroelectric power plants
Wind and solar generators
Used for
Motors
Heaters
Lights
Anything that plugs into the wall

42. Electricity and Magnetism
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
What is a Magnet?
An object that is surrounded by a magnetic field and has the property of attracting iron or steel

43. Image courtesy of DOE/NREL
Electricity and Magnetism
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Where are Magnets?
Magnets. . .
Generate electricity
Image courtesy of DOE/NREL
Image courtesy of DOE/NREL
Are in motors
Generate electricity: Turbines are turned at power plants by heated steam, water pressure, etc., to spin a turbine surrounded by magnets to generate electricity. Students will make a generator in an upcoming activity.
Motors spin because of the magnetic field that is created from electricity. Students will create a motor in an upcoming activity.

44. Where are Magnets? Magnets. . . Power car windows & locks
Electricity and Magnetism
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Where are Magnets?
Magnets. . .
Power car windows & locks
Image courtesy of NASA
Are used in Magnetic Resonance Imaging (MRI)
Power windows use a small motor, and power door locks use a solenoid. The clicking noise heard when the mechanisms lock or unlock is the release and activation of an electromagnet. Students will create an electromagnet in an upcoming activity.

45. If a large magnet breaks into the small pieces what will their poles be?

46. North and South Poles of a Magnet
Electricity and Magnetism
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
North and South Poles of a Magnet
Magnets have a north and south pole.
If a magnet is broken into smaller pieces, each piece will still have a north and south pole.
Opposite poles attract, like poles repel. N S N S S N N S N S N S N S N S N S

47. How do compasses work?

48. The Earth as a Magnet The Earth is a large magnet.
Electricity and Magnetism
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
The Earth as a Magnet
The Earth is a large magnet.
North Pole
South Pole
Compasses work as a result of the Earth’s magnetic field.

49. What is an electromagnet?

50. Electricity and Magnetism
Gateway To Technology®
Unit 4 – Lesson 4.1 – What is Electricity?
Electromagnets
Magnets are created by passing a current through a wire.
Electromagnets are generally wire wrapped around an iron core.
Electromagnets are turned on and off when the current is switched on and off.

51. How can you switch the poles of an electromagnet?

52. Motors and Generators
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
Electromagnets S N S
Electromagnet ends change between north and south depending on the direction of the current. N

53. What parts make up a motor?

54. Parts of a Basic DC Motor
Motors and Generators
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
Parts of a Basic DC Motor
Motor: A device used to convert electric energy into mechanical energy.
Brush
DC Source
Commutator
Armature
Permanent
Magnet
DC Source: Provides electric current.
Permanent Magnets: Also known as field magnets, these magnets provide the magnetic field for the motor.
Brushes: Transfer power from the source to the slip rings.
Commutator: Also known as a slip rings. Transfer the power from the DC source to the armature. The design of the slip rings are what allow the current to reverse direction. The current reversing direction causes the electromagnet to reverse polarity. This can clearly be seen in the animation.
Armature: The electromagnet that spins to create rotary motion. N N S S
Permanent
Magnet
Commutator
Brush

55. Parts of a Small DC Motor
Motors and Generators
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
Parts of a Small DC Motor
Brushes
Wire
Connections
Permanent
Magnets
Armature
Commutator

56. What is an electric generator?

57. Electric Generators N N S S
Motors and Generators
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
Electric Generators
Generator: A device used to convert mechanical energy into electrical energy.
Mechanical motion turns the armature which creates current.
Many DC motors can function as a generator. N N S S

58. Explain the steps by which electricity goes from the power plant to your home.

59. From the Power Plant to Your Home
Motors and Generators
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
From the Power Plant to Your Home
Most electricity is produced using turbines. Turbines spin to create electricity. Usually turbines are turned using hot pressurized steam. Turbines are also often turned by wind or water pressure behind dams.
Image courtesy of Sacramento Municipal Utility District
Power plants generate electricity.

60. From the Power Plant to Your Home
Motors and Generators
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
From the Power Plant to Your Home
Generally the transformers at a power plant step up the voltage, whereas transformers at substations and on utility poles generally step down voltage. Power may be stepped down two to three times before it reaches buildings and homes.
The higher voltage increases efficiency because there is less heat loss.
Step up transformers increase voltage for transmission across large towers.
Increased voltage increases efficiency.

61. From the Power Plant to Your Home
Motors and Generators
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
From the Power Plant to Your Home
Large towers transmit electricity over long distances.
Images courtesy of DOE / NREL

62. From the Power Plant to Your Home
Motors and Generators
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
From the Power Plant to Your Home
Step down transformers reduce voltage at substations to acceptable levels for the end user.

63. From the Power Plant to Your Home
Motors and Generators
Gateway To Technology
Unit 6 – Lesson 6.1 – What is Electricity?
From the Power Plant to Your Home
Electricity arrives at your home at a junction box.
Usage is measured with a meter.

64. Briefly explain how Maglev Trains work