Learning
Guide
Guide
Year 8 Wind Energy
Image: KidWind
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Year 8 Wind Energy
Learning Guide
Wind Energy activity: Year 8
Contents
Wind Energy activity: Year 8 .......................................................................................................................... 2
Overview .............................................................................................................................................. 3
Getting started .................................................................................................................................... 3
Explore more ....................................................................................................................................... 4
Challenge 1 .......................................................................................................................................... 5
Challenge 2 (Extension) ....................................................................................................................... 5
What is your idea? ............................................................................................................................ 5
Fair testing ........................................................................................................................................ 6
Reporting .......................................................................................................................................... 7
Challenge 3 (optional) ......................................................................................................................... 7
Need to know: .................................................................................................................................. 7
Getting started.................................................................................................................................. 7
Investigate more ............................................................................................................................... 8
Reporting .......................................................................................................................................... 8
Evaluation ......................................................................................................................................... 8
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Year 8 Wind Energy
Learning Guide
Overview
Introduction
In the first part of this activity you will find out about wind turbines and how they can convert wind
energy for doing useful work. Then you will investigate how a wind generator can produce energy for
electric circuits to function. You will then apply these ideas to meet a challenge of constructing a wind
generator to light up as many LED lights as possible.
Think about: Where have you seen wind turbines being used? What type of tasks do they perform?
Have you noticed the different designs of the turbine blades? How are they different? Why do you think
they are different?
Getting started
What is the effect of wind speed on the rotation speed of a turbine?
1. Start with a turbine such as the mini turbine placed a fixed distance from the wind source (fan).
It might be helpful to tie streamers on the fan grill to show the effects of the fan wind.
2. Think about: What is the source of energy? What type of energy conversion does the turbine
perform? What use can be made of this type of convertor?
3. Try the turbine at different distances and then try different fan speed settings. Observe the
changes in spin speed of the turbine for each of the distances and settings. What did you notice?
4. Try to make the turbine spin as fast as possible. Where did you position the turbine for the
fastest? What speed setting on the fan did you choose? How would you setup for the slowest
spin speed?
5. Substitute the mini turbine for a quick fit hub with a basic 3 blade design for the turbine. Trial
this new setup at different distances and speeds. Can you measure the spin speed? Hint: colour
one blade as a marker. Count the number of spins for a fixed time. How long should that be?
Give an answer in revolutions per minute or rpm. This is the number of complete rotations in 1
minute.
Checkpoint:
1. Moving air (wind energy) can be converted into rotating motion (kinetic energy) of a turbine.
2. The faster the moving air is moving then the faster is the rotation of the turbine blades.
3. Speed of rotation can be measured as the number of revolutions per minute known as rpm.
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Year 8 Wind Energy
Learning Guide
Explore more
How much wind energy can be converted into rotational energy?
1.
How to measure the energy output of the rotating turbine:
a. Attach the weight lifting nacelle then lift a single weight.
b. Now measure the spin speed as before. How does it compare to the speed without a
weight?
c. What happens to the spin speed when lifting weights?
d. What form(s) of energy does the rotating energy convert into?
e. How can some of this energy conversion be measured?
2. Is there a limit to how much weight the turbine can lift?
a. Make predictions about the limits and then test to find the greatest weight that can still
be lifted to the top i.e. the weight still has to move up.
b. Why is there a limit for how much weight that can be lifted?
c. What is the weight when the speed is zero? What has happened to the rotating energy
in this case?
3. How can you measure the energy that is converted from the wind turbine? (extension)
a. Measure the weight that is lifted.
Calculate weight in Newtons (N) = mass (kg) x gravitational acceleration (9.8m/s2)
Weight (N) = mass (kg) x 9.8 m/s2
b. Measure the height that that the weight reaches above the ground in metres (m).
c. The gravitational energy (Joules) of the weight is found by the product of the weight
(Newtons) and the height (metres).
Gravitational Energy (J) = Weight (N) x height (m)
Checkpoint:
1. Moving air (energy) can be converted into rotating motion that can apply a force to lift weights.
2. The speed of rotation and the turning force have limits set by the wind source and the distance
from it.
3. Speed decreases as the weight lifted increases. There is maximum weight that can be lifted due
to the design of the turbine and the available wind energy.
4. The wind energy that is converted into gravitational energy can be measured.
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Year 8 Wind Energy
Learning Guide
Challenge 1
Can you design the turbine to increase the energy output?
1. Brainstorm some ideas: In your discussion group try to suggest as many ideas as possible to lift
more weight. For each idea ask the question: How does your idea make the turbine spin faster?
2. In your group choose three ideas that you think will make the most improvement to lifting
weight. Why did you choose these ideas?
3. Testing one idea at a time, make some changes to the turbine to test your prediction about
improvement in weight lifting. Record what happens for each test. What did you find out?
4. Now choose the one idea that you think will make the most difference. This is your best idea.
You are ready for some more investigation of this idea.
Checkpoint:
1. The turbine can lift more weight by changing the blade design.
2. Some blade design ideas can produce better energy conversion output improvements than
others.
3. Improvements in energy outputs are due to changes in blade design that improve the rotating
speed of the turbine.
Challenge 2 (Extension)
Can you find the best improvement in energy output for your idea?
Here are some examples of what you might test:
If your idea is that blade angle will make the best improvement then what is the best angle?
If your idea is that the number of blades will make the best improvement then what is the best
number?
If your idea is that the size of the blades will make the best improvement then what is the best size?
What is your idea?
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Year 8 Wind Energy
Learning Guide
Fair testing
1. Think about: How will you test your idea to find the best improvement in energy output? How
will you make a fair test so that you know the effect of your idea? What are some of the other
variables (ideas) that could have an effect? How will you make sure that only your best idea is
being tested?
2. You should prepare for your testing by doing all of the following:
a. Write down your best idea. This is your variable to test.
b. Draw what your will blades will look like.
c. Write down how you will keep all other variables the same.
d. Prepare a data recording table to record all your test results.
3. You can use the turbine from the previous challenge. Ask your teacher for more materials to test
your variable if needed.
4. First test: Baseline data is collected by the starting turbine at a fixed distance from the fan set at
a fixed speed. Prepare a data table to record the following:
a. Record the speed of the rotating turbine without lifting weights.
b. Record the speed of the rotating turbine when lifting the maximum weight.
c. Record the maximum weight and the height lifted.
5. In your group you should consider the changes you wish to make to the turbine blades variable.
Try to test using simple changes of the variable. E.g. add one blade at a time if increasing the
blade number. Keep all other variables the same! Watch out for balancing problems. The
blades must be identical and evenly spaced on the hub. Why?
6. Draw a table to collect all your data. It might look something like this if you are testing the effect
of the number of blades:
Results (EXAMPLE ONLY)
Test
Blade variable
Weight lifted
Spin speed
(no weight)
Baseline 3 blades
Test 2
4 blades
Test 3
5 blades
Test 4
Test 5
6 blades
7 blades
Test 6
Test 7
8 blades
9 blades
Observation comment
Not tested because could not
space blades evenly on hub
Not tested because could not
space blades evenly on hub
7. Second test: Test the modified turbine at the same distance and fan speed. Record the
maximum lifting weight and the spin speed of the turbine.
8. Third test etc.: Continue testing as required to achieve the maximum lifting weight until all
reasonable changes have been completed.
9. Testing other variables will need to start from another set of identical blades if you have time.
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Year 8 Wind Energy
Learning Guide
Reporting
Collect all data tables and look at results. You will be asked to report on what you found out. Discuss this
with your group.
1. Did your variable make the turbine lift more weight? How much difference did it make?
2. What was the best maximum weight achieved. What was the variable value at this time?
3. What happened to speed as weight that could be lifted increased?
Checkpoint:
1. You should know how to change a blade variable to change the performance of a turbine.
2. You should know that as weight is lifted the spin speed of a turbine deceases.
Challenge 3 (optional)
Can you construct a wind turbine that will generate sufficient electricity to light
an LED?
Need to know:
The LED needs a minimum voltage and current to work. For this requirement the electrical generator
needs a high speed turbine. A spinning turbine is storage of kinetic energy to be converted into electrical
energy to light up the LEDs. Increasing rotating kinetic energy is one way to increase the electrical
energy available for lighting the LEDs.
Getting started
1. Use the mini-turbine blade to light a LED.
a. What happens to the speed when the LED turns ON?
b. Why does the speed change? Talk about energy changes in your explanation.
2. You could try another globe (incandescent) now if available.
a. What happens? Did the globe light up?
b. What happened to the turbine speed?
c. Why does the turbine slow right down? What is happening to the energy?
3. Now try your best weight lifting design see if it can also light the LED. Not working? Measure the
voltage with a meter without the LED connected then with the LED connected. What do you
notice? Why is this happening? Refer back to “Need to Know” section for some clues for an
explanation.
Checkpoint:
1. The LED needs at least 2.5V before it will light up. The generator must also supply enough
current for it to work.
2. An electrical generator must be able to maintain enough spin speed while lighting a globe to
provide sufficient voltage and current for the LED to light up.
3. Reduction in speed of the turbine is evidence of energy being drawn from the system.
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Year 8 Wind Energy
Learning Guide
Investigate more
1. You need to design your turbine so that it has enough speed to provide energy to light more
than one LED. You will also need to decide if it is better to connect your LEDs in series or in
parallel. To find this out you could conduct some tests with 2 LEDs and two 1.5V batteries. See
your teacher for help with this.
2. What type of blades will work best? Look at some images of wind generators below and
compare them to the water windmill in the centre. What are the differences? Why are they
different?
Images: KidWind
3. How could the weight lifting design be modified to achieve a better performance? i.e. How can
you make the LED work?
Brainstorm ideas: use the mini-turbine model as a guide. The design needs speed as well as
turning force this time. A minimum 2.5V is required to light the LED (in this kit).
4. You should create your own investigation using the same process that you followed in
Challenges 1 and 2. All principles of “fair testing” still apply as before:
a. Change one variable and keep all others the same
b. Change variable in increments that can be easily measured
c. All data must be recorded
d. If one LED can be lit then try for a second in series or try to light an incandescent bulb.
Record results.
5. Once you have one LED working, try to light a second LED. Try connecting the LEDs in series and
then in parallel to find out if there is difference. What did you find out?
Reporting
Collect all data tables and look at results. Your group will be asked to report on what you found out.
Did your design make the turbine light the LED? What was the highest number of LEDs achieved? Was it
possible to light an incandescent bulb?
Evaluation
You should think about what you have learned. Which idea do you think worked best? What would you
like to try next? Would you some of the ideas from this test in your next design?
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Year 8 Wind Energy
Learning Guide
Disclaimer
This activity has not been validated by specific testing with students in a classroom setting. As such it only represents ideas for
using the wind turbine as a context for learning about forces and machines. It is not intended as a definitive guide and should
be modified or used as a model to develop suitable activities for your own classroom context including risk assessments.
Acknowledgements
These activities are based on materials and ideas from the KidWind organization and adapted for the Australian Curriculum:
Science.
KidWind: http://learn.kidwind.org/
KidWind Project, 800 Transfer Rd, Suite 30B, Saint Paul, MN 55114
Copyright notice
Prepared by: Scientrific Learning
© Scientrific Pty Ltd 2013
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For all Australian Curriculum material except elaborations: This is an extract from the Australian Curriculum.
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