year 8 Science Unit of Renewable Energy includes: voltage and current, solar panels and wind turbines

1. RENEWABLE ENERGY
YR. 8 SCIENCE

2. ELECTRIC CIRCUIT SYMBOLS
symbols used in electric
circuits:
**REMEMBER:
when drawing
circuit diagrams, Always
use a Lead Pencil and a
Ruler

3. Drawing Circuits
 1) Draw a circuit with a battery and lamp.
 2) Draw a circuit with a battery, lamp and open
switch.
 3) Draw a circuit with a Battery, two lamps and a
closed switch.

4. Series Circuit:
there is only 1 path for the
electricity to flow along.
https://www.youtube.com/watch?v=RQ3djos_LY8
 Parallel Circuit:
there is more than1 path
for the electricity to
flow along.

5. SERIES AND PARALLEL CIRCUITS
• Conduct the experiment on series and parallel
• circuits
• Investigate how they differ?
• Record all answers on your practical sheet

6. CURRENT & VOLTAGE
Current: the rate of flow of electrons flowing along a wire in an
electric circuit.
Measured in: amperes, or amps for short (A).
Ammeter: device used for
measuring current
**Ammeter be placed in series in the circuit

7. CURRENT & VOLTAGE
Voltage: a measure of the electrical energy that causes an electric
current to flow.
Also known as potential difference
measured in: volts (V).
measuring a difference
in voltage,
you must connect the
voltmeter in
parallel across the
component whose
voltage you want to
measure
Voltmeter: device used
for
measuring voltage.
http://www.youtube.com/watch?v=G1wU8AYGD7Q

8. Electrical Energy: energy possessed by electrons in an
electric circuit. Measured in joules (J).
Electrical power: a measure of how
much energy is transformed per second
in an electric circuit. measured in
units called watts (W).
1 W (watts) = 1 J/s (Joules/second)
ELECTRICAL POWER

9. ELECTRICAL POWER
P= VI
The electrical power delivered (i.e. transformed)
by an energy source can be calculated from the
voltage across the energy source, and the amount
of current flowing in the circuit.
P = electrical power
(W)
V = voltage (V)
I = current (A)
The following formula is used:

10. ELECTRICAL POWER Calculations
1) Voltage was 4V and Current was 16A what was the
electrical power?
2)If Current was 10A and Voltage was 6.5V what would
electrical power be?
P= VI
3)The Voltmeter has a reading of
1.5 V and the Ammeter has a
reading of 25mA what is the
amount of electrical power ?

11. ELECTRICAL POWER Experiment
Measurement Lamp Buzzer Fan LED
Voltage (V)
Current
(mA)
Power (mW)
• Measuring the current and the voltage delivered by the STELR
battery to the various components on the STELR testing station.
• We will be able to calculate the power (P = VI) delivered to each
part.
• Fill in your results in the table

12. Transforms the kinetic energy of the
wind into mechanical energy of the
turbine
then the generator transforms it into
electricity.
A good site for wind turbines might have
a 35% capacity factor.
Good sights for Wind turbines?
WIND TURBINES
https://www.youtube.com/watch?v=a09vHnVrBi0

13. Eyre Peninsula: Port Lincoln
Fleurieu Peninsula: Cape Jervis
Hallet Hill (Burra, Jamestown area)
- Away from obstacles
- Highest point possible
- Clear space around 10 times
the height of the local
•Best place on
top of smooth
hilltop

14. WIND TURBINES
 Some energy is wasted, due to the fact that some is
transformed into heat and sound energy.
 A set of wind turbines that are linked together to
supply electricity for a larger population= a wind
farm.
 Is there a difference between a windmill and wind
turbine?
https://www.youtube.com/watch?v=tsZITSeQFR0

15. WIND TURBINES
Advantages of Wind Turbines:
1. They are a renewable energy
source.
2. They do not emit
greenhouse gases.
3. They are more energy
efficient than most power
stations that burn fossil fuels.

16. WIND TURBINES
Advantages of Wind Turbines:
4. They are cheaper to run than many other energy
resources.
5. They can be established in remote areas.

17. WIND TURBINES
DISADVANTAGES OF WIND TURBINES:
1. The electrical power delivered
varies because wind speed and
direction vary.
2. They can be damaged by strong
winds and corroded by salt in the air
when near the sea.
3. It can be costly to connect them
to the grid, due to the large
distances involved.

18. WIND TURBINES
DISADVANTAGES OF WIND TURBINES:
4.Some people believe the sound
produced by wind turbines is
annoying or even harmful.
5. Some people think they spoil
the landscape.
6. Injury or death of birds and
animals
https://www.youtube.com/watch?v=79aARWPalt4
https://www.youtube.com/watch?v=lm0Oe8J6qT8

19. Measure the power delivered by the STELR model wind turbine,
and determine how this is affected by the number of blades.
Number of turbine
blades
2 3 4 6 12
Electrical Power (mW)
(P=VI)

20. HOW DOES BLADE LENGTH
AFFECT THE OUTPUT OF A WIND TURBINE?
• Measure the power delivered by the STELR model wind turbine, and determine how
this is affected by the length of the blades.
• All groups will set their blade angles to 45.
• Each group will compare the number of blades . Starting at:
1. 12 blades
2. 6 blades
3. 4 blades
4. 3 blades
5. 2 blades
• Record Results in table: Voltage (V) & Current (mA)
• Calculate Electrical Power: P=VI
Show your
working
out!!!

21. Measure the power delivered by the STELR model wind turbine,
and determine how this is affected by the length of the blades

22. Graphing Wind Turbine
Results
Graph 1
O Discrete Data: how many blades practical
O Independent variable: No. of blades
O Dependent: Power (mw)
Graph 2
O Continuous Data: Blade
length
O Independent variable: Blade
lengths
O Dependent: Power (mw)
https://www.youtube.com/watch?v=niZ_cvu9Fts

23. SOLAR CELLS
Solar cells, also known as photovoltaic (or pv) cells
Converts the energy from the Sun (i.e. solar energy)
directly into electricity.
A solar panel consists
of a set of solar cells

24. Are connected together to
produce a desired voltage
and current.
A solar array is a set of
solar panels connected
in a grid
Found on the rooftops of
buildings to help meet their
energy requirements.
https://www.youtube.com/watch?v=NDZzAIcCQ
LQ

25. 1.1 percent of Australia's electrical
energy comes from solar panels
Solar Power Projects
in South Australia
Adelaide
Showgrounds
Wilpena pound'Australia's largest'
solar farm Royalla,
south of Canberra
83,000 solar panels and can power
more than 4,500 ACT homes
https://www.youtube.com/watch?v=YD6m98mRBMQ

26. ENERGY SPELLING WORDS
11. appliance
12. conservation
13. destroyed
14. efficiency
15. bicycle
16. renewable
17. alternative
18. geothermal
19. turbine
20. photovoltaic
1. energy
2. kinetic
3. potential
4. gravitational
5. electricity
6. transfer
7. transformation
8. battery
9. kilojoules
10. parallel

27. Four Solar Cells from
the Sun

28. Solar Cells
Advantages of Solar Panels:
1. They are a renewable energy source.
2. They do not emit greenhouse
gases.
3. Solar energy is free and the panels
have a long life.

29. 4. They operate without noise.
5. They can be used in remote areas (e.g. space) where
there is no access to an electricity grid.
Solar Cells
Advantages of Solar Panels:
6. The heat energy
produced can also be
used to heat water.
https://www.youtube.com/watch?v=x4CTceusK9I

30. SOLAR CELLS
DISADVANTAGES OF SOLAR PANELS:
1. The amount of power they generate varies
due to the changing position of the Sun,
cloud cover, etc.
2. They are expensive to install.
3. Greenhouse gases are made during
manufacture,
transport and installation of solar panels.

31. 5. They do not produce
power at night.
SOLAR CELLS
DISADVANTAGES OF SOLAR PANELS:
4. Some people do not like
their appearance.
6. They have low energy
efficiency ( 10 – 15%).

32. Four Solar Cells from
the Sun

33. ENERGY SPELLING WORDS
1. energy
2. kinetic
3. potential
4. gravitational
5. electricity
6. transfer
7. transformation
8. battery
9. kilojoules
10. parallel
11. appliance
12. conservation
13. destroyed
14. efficiency
15. bicycle
16. renewable
17. alternative
18. geothermal
19. turbine
20. photovoltaic