1. ELECTRICITY:
Creating Current

2. Electricity Generator
OUTCOME QUESTION(S):
S1-3-08:
What is “electricity” and how is it created?
Vocabulary & Concepts 
Electricity Generator

3. (Current) Electricity:
Creating “Electricity”
Different sources exist for creating energy from free electrons and generating an electric current
Batteries
Solar Panels
Hydro Dams …
What other ways have you seen to create electricity?
(Current) Electricity:
the flow of electrons around a circuit.

4. Essentially just converting one form of energy into another form
Most electricity is creating using two basic steps:
Remove electrons from one location (takes energy)
Let electrons flow back (releases energy)
Essentially just converting one form of energy into another form

5. More detail to come on batteries….
1. Chemical: source converts chemical energy into electrical energy.
Reaction separates electrons from metal (+)
Energized electrons collect at other metal (-)
Electrons flow back to (+) metal
More detail to come on batteries….

6. 2. Thermoelectric: source converts heat energy into electrical energy.
Metals heated at one end and cooled at other
Energized electrons flow towards cool side
Called a thermocouple / thermopile
Thermocouples are used as safety control devices in furnaces, engines and appliances

7. 3. Photoelectric: source converts solar energy into electrical energy.
Light energy separates electrons from material
Energized electrons accumulate on “collector”
Creates a weak flow of electrons
Remember: visible light is just one form of wave around us -
Some are low energy (radio wave) some high energy (x-ray)

8. Piezo comes from the Greek word meaning pressure
4. Piezoelectric: source converts mechanical energy into electrical energy.
(some) Materials polarize when squeezed
various crystals, ceramics, bone
Creates charge separation across the faces
Electrons flow when faces are connected
Piezo comes from the Greek word meaning pressure

9. The piezoelectric effect also works in reverse:
Applying current to a crystal causes it to change
shape (vibrate)
Ultrasound machines, sonar, microphones, watches/clocks, push lighters, all use the piezoelectric effect

10. Device is called a generator
5. Electromagnetic: source converts mechanical energy into electrical energy.
Coil of wire spinning through a magnet creates a flow of energized electrons
Device is called a generator
An energy source is needed to turn generator
– wood, coal, falling water, nuclear reaction…

11. 97.6% of Manitoba energy comes from dammed water turning the generator to create the electricity

12. STATIC Vs. CURRENT ELECTRICITY
SIMILAR
DIFFERENT
Both: need input of energy to
create charge
(friction or other source)
Static: displaced electrons are
localized
Current: displaced electrons
move
Both: 1st step is charge separation
2nd step is charge transfer
(neutral object or battery)
Static: brief transfer of small
amounts of charge
Current: continued transfer of
large amounts of charge
Both: will discharge (run out)
when all electric charge is
transferred back
Static: discharges randomly
Current: discharges through a
conducting path

13. CAN YOU ANSWER THESE QUESTIONS? S1-3-011:
What is “electricity” and how is it created?
Vocabulary & Concepts 
Electricity Generator

14. CURRENT ELECTRICITY:
Components

15. Volt Voltmeter Current Ampere Ammeter Resistance Resistor Ohm Load
OUTCOME QUESTION(S):
S1-3-09/10/12:
What do current, voltage and resistance mean for electrons?
Vocabulary & Concepts 
Cell Coulomb Voltage
Volt Voltmeter Current
Ampere Ammeter Resistance
Resistor Ohm Load

16. metal to lose electrons – (-) electrode (anode)
Cell: device that uses a chemical reaction to create a flow of electrons between different materials.
NEED:
metal to lose electrons – (-) electrode (anode)
metal to gain electrons – (+) electrode (cathode)
chemically reacting substance – electrolyte
The acidic lemon juice acts as the electrolyte to aid the chemical reaction

17. Rod: (+) electrode (cathode)
The original Voltaic “wet” cell does not have practical use today and has been replaced by the “dry” cell - battery
Rod: (+) electrode (cathode)
Casing: (-) electrode (anode)
electrolyte paste

18. Electrons are measured and counted in bundles called a coulomb:
Cell Measurements:
Electrons are measured and counted in bundles called a coulomb:
1 coulomb = 6.25 quintillion (6.25 x 1018) electrons
Think of a coulomb as very, very large “dozen”
1. Voltage (V)
Electrical potential of electrons in a source:
electrons convert their potential energy into work
Potential: unrealized ability to accomplish something
Voltage: energy the electrons have to potentially do something

19. Measured by a Voltmeter Units: Volt (V)= Q E
E is energy/work potential in joules
Q is the number of coulombs
Voltage (volts) measures the potential energy available in every coulomb of electrons
As electrons move to the other end of the source they lose all potential (stored) energy

20. 1.5 joules of energy released by every coulomb of electrons
1.5 Volt battery
1.5 joules of energy released by every coulomb of electrons
0 Volts
(+) electrode
(-) electrode
electrolyte paste
1.5 Volts
550 V – typical Power station
120 V – typical wall outlet
1.5 V – typical battery

21. 2. Current (I)
The rate (speed) at which electrons move through the conductor.
Measured by an Ammeter
Units: Ampere /Amps (A) I = t Q
Q is the number of coulombs
t is time in seconds
Current (amps) measures the number of electrons passing a point every second

22. 1 Amp = electrons moving at a rate of
1 coulomb per second
0.83 A – current needed for a typical light bulb
0.2 A – severe burns, heart stops, lungs stop
(“let go” threshold)
0.02 A – breathing affected, muscles contract
0.002 A – muscles tingle (good shock)
Its not the voltage that kills, it’s the current: the number of electrons running through you

23. Energy taken is converted as work or lost as heat
3. Resistance (R)
Anything that slows down electrons and takes potential energy away in the process.
Resistors are electrical components used to control the current and voltage to protect the device.
Units: ohm (Ω)
The loss of potential energy as electrons slow through a resistor is called the “voltage drop”
Energy taken is converted as work or lost as heat

24. e- Load + - e- a resistor that converts energy for use Resistor● + -
Load
a resistor that
converts energy for use
Resistor
slows electrons and
take energy as heat e-
Even the conducting wire provides some resistance – takes some energy away converting it to heat

25. CAN YOU ANSWER THESE QUESTIONS? S1-3-09/10/12:
What do current, voltage and resistance mean for electrons?
Vocabulary & Concepts 
Cell Coulomb Voltage
Volt Voltmeter Current
Ampere Ammeter Resistance
Resistor Ohm Load