Teaching sequence

Work through this resource material in the following sequence:

10 minutes

Tune In: What makes a windmill spin?

20 minutes

Find Out: Balanced and unbalanced forces driving renewable energy

25 minutes

Take Action: Engineering efficiency

5 minutes

Reflection

Learning intentions and success criteria

Students will:

explore how balanced and unbalanced forces affect the efficiency of wind turbines and hydro systems
identify the role of engineering in enhancing renewable energy technologies.

Students can:

show how balanced and unbalanced forces act on wind turbines and pumped hydro systems using annotated diagrams
describe the role of engineering in improving the efficiency of renewable energy technologies by harnessing or mitigating specific forces.

Tune In: What makes a windmill spin?

Curriculum Connections

In this lesson students investigate the impacts of forces on wind and hydro turbines and how these forces impact efficiency. This Year 7 unit also includes a Design and Technologies lesson that looks into how force and motion are harnessed to generate electricity in wind turbines and gets students to design wind turbines, modifying them for efficiency. Cool.org recommends that Science and Design and Technology teachers collaborate to deliver these content materials across their respective subjects so students can understand the content from multiple STEM perspectives and reuse their turbines across these subjects.

Preparation

The previous lesson in this unit, Measuring the Power of Wind and Water, explored how balanced and unbalanced forces affect the function of hydro and wind turbines. If you completed this lesson with your students, you might like to conduct Step 1 of this lesson using the turbines your class created. If you have yet to complete the previous lesson, use the paper turbine template provided to get students to think about how forces affect structures such as this.

Step 1

Divide the class into pairs and distribute the Paper Turbine Template to each student so that there is 1 between each pair. Each pair should make a turbine following the instructions on the template.

Step 2

Ask students to use their breath to move the turbine. As they make the turbine work, ask them to observe and think about what forces might be acting on the paper windmill they have created. Encourage students to think about forces such as gravity, friction, wind and air resistance. Discuss their observations and provide guiding questions like:

What makes the blades of the windmill move?
What makes them move faster or slower?
What prevents the blades from spinning forever?

Step 3

Ask students to brainstorm what forces would be acting on this windmill if it was in flowing water.

Find Out: Balanced and unbalanced forces driving renewable energy

Step 1

In the same pairs, provide students with the Student Worksheet, which features the links to the following short videos demonstrating wind turbines and hydro systems in action throughout Queensland.

Wind: Energising Queensland - Octopus Australia | Blade Hype (youtube.com/watch?v=hHkW3zeMKQQ)
Hydro: Pumped Hydro in Queensland (youtube.com/watch?v=h53Vnx0XbUo)

In pairs, 1 student should watch the wind turbine video, and the other should watch the pumped hydro video. As they watch, encourage students to label their diagrams with what balanced and unbalanced forces make each type of renewable energy work.

If your students can’t access YouTube on their personal devices, you might like to watch these videos as a class and invite students to annotate each diagram as you watch together.

Step 2

Invite students to share their responses with their pair and annotate the other type of renewable energy. Discuss these observations as a class.

Step 3

Briefly explain the balanced and unbalanced forces acting on wind and hydro turbines to produce renewable energy using the images on the attached Visual Explainer.

Wind energy

Wind (unbalanced force) causes the turbine blades to move, while gravity (balanced force) acts to keep the blades in place. You might like to discuss drag, lift, centrifugal and gravitational forces using the rest of the images. The wind force acting on the blades is an unbalanced force that causes rotation, the gravitational force pulls the tower and nacelle downward, and the frictional forces act at the pivot points and generator.

Hydropower

Water pressure (an unbalanced force) moves water through the system, while gravity (a balanced force) affects the water’s flow when it’s pumped up or released. There are also frictional forces in the turbines and pipes.

mped up or released. There are also frictional forces in the turbines and pipes.

Step 4

Show students the next slide of the Visual Explainer, which features the following information. Task students with using the information below to add more detail to their initial annotations.

	Balanced forces	Unbalanced forces
Wind power	Centrifugal: Acts outward from the centre of the rotating blades. In a steady state, it is balanced by the tension in the blades and aerodynamic forces. Gravitational: Acts downward due to gravity. In a stationary or steady rotating system, it is balanced by the structural support of the wind turbine tower and the aerodynamic lift forces.	Drag: Acts against the motion of the blades, causing resistance and slowing them down. Lift: Acts perpendicular to the wind direction and is responsible for rotating the blades. It is crucial for the conversion of wind energy into mechanical energy.
Hydro-power	Gravitational: The weight of the water in the reservoirs is balanced by the structural support of the reservoirs and the surrounding ground. Hydrostatic Pressure: The pressure exerted by the water at rest in the reservoirs is balanced by the pressure exerted by the walls of the reservoirs.	Pump: When water is being pumped from the lower reservoir to the upper reservoir, the force exerted by the pump is unbalanced, causing the water to move uphill. Turbine: When water flows from the upper reservoir to the lower reservoir, the force exerted by the falling water on the turbine blades is unbalanced, causing the turbine to rotate and generate electricity. Frictional: During the flow of water through pipes and turbines, frictional forces act against the motion of the water, causing energy losses. This is an unbalanced force that needs to be overcome by the system.

Step 5

Explain to students that efficiency is a major factor in designing and constructing wind turbines. Efficiency means that a high percentage of the forces harnessed are converted to the desired energy.

Discuss the following with your students and ask them to annotate their images with their answers by highlighting the force/s they think are responsible:

What forces explored above might act to decrease the efficiency of the particular renewable energy?
What forces explored above could be harnessed to increase the efficiency of the particular renewable energy?

Take Action: Engineering efficiency

Step 1

Ask students what needs to be done to enhance the efficiency of wind power or hydropower, or what needs to be done to mitigate the effects of unwanted forces.

Lead students to the idea that these renewable energy technologies need to be engineered or designed to take these factors into account.

Step 2

Divide students into small groups and provide each group with a link to the Future Energy Jobs Guide. Challenge students to skim through the guide to find out whose job it is to design wind turbines to be efficient.

Suggested response:

Mechanical engineers and chemical engineers on pages 36 and 37

Discuss how 80% of Queensland’s electricity will come from renewables by 2035 (Source: Future Energy Jobs Guide), which means there will be many career opportunities in this field in the future.

Step 3

Once students have determined who is responsible for engineering efficiency, allocate each group to either wind or hydropower. Their task is to research the role and responsibilities of mechanical engineers and find out how they design more efficient renewable energies by lessening the impact of unwanted forces when harnessing the renewable forces of wind and water.

Encourage students to structure their research tasks using both the Future Energy Jobs Guide and the guiding questions and information below.

If students need a refresher on renewable energy types, they can rewatch the videos from the previous section of the lesson.

MacIntyre Wind Farm (Optional) Watch a short video of Alice, site engineer at the MacIntyre Wind Farm in Warwick, Queensland to understand what your renewable energy project is all about.	Kidston Pumped Hydro (Optional) Watch a short video of Gurpinger Mand, site engineer at Genex Power’s Kidston Pumped Storage Hydro Project in Far North Queensland to understand what your renewable energy project is all about.
What career type/types are involved in ensuring wind power is as efficient as possible? (Hint use the Future Energy Jobs Guide)	What career type/types are involved in ensuring hydropower is as efficient as possible? Hint, use the Future Energy Jobs Guide)
What roles and responsibilities do these careers have that allow them to do this?	What roles and responsibilities do these careers have that allow them to do this?
Why is engineering efficiency of renewable energy important? Note: Think about this statement: “The Queensland Energy and Jobs Plan sets out our state’s bold vision to achieve 70% renewable energy by 2032 and 80% by 2035. “	Why is engineering efficiency of renewable energy important? Note: Think about this statement: “The Queensland Energy and Jobs Plan sets out our state’s bold vision to achieve 70% renewable energy by 2032 and 80% by 2035. “
What are at least 2 design factors that improve the efficiency of wind power by harnessing force?	What are at least 2 design factors that improve the efficiency of your hydropower by harnessing force?
What are at least 2 design factors that improve the efficiency of wind power by lessening the impact of an unwanted force?	What are at least 2 design factors that improve the efficiency of hydropower by lessening the impact of an unwanted force?
What 3 questions would you ask the engineers at MacIntyre to learn more about the efficiency of their turbines?	What 3 questions would you ask the engineers at Kidston to learn more about the efficiency of their hydropower?

Step 4

Discuss students’ findings as a class, focusing on the importance of engineering renewable energy efficiently for society's current needs.

Reflection

Reflect on the lesson with your students by using the following questions:

How did exploring the examples in this lesson help you understand the forces affecting wind farms and hydro stations?
Did you have an interest in any of the career opportunities that were presented in this field?

The Forces Behind Efficiency in Renewable Energy

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The Forces Behind Efficiency in Renewable Energy

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