Teaching sequence

Work through this resource material in the following sequence:

10 minutes

Tune In: Understanding forces in renewable energy

10 minutes

Find Out: Investigating forces through experiments

35 minutes

Take Action: Testing turbines

5 minutes

Reflection

Learning intentions and success criteria

Students will:

understand how balanced and unbalanced forces influence the operation of wind turbines and hydro turbines, and how force magnitude and direction affect these energy systems.

Students can:

measure the magnitude of a force using a force meter, and represent the magnitude and direction of forces acting on an object using force arrow diagrams
conduct experiments to observe how varying amounts of force affect the performance of wind turbines and hydro turbines
analyse how changing the force impacts the efficiency and functionality of wind turbines and hydro turbines.

Tune In: Understanding forces in renewable energy

Curriculum Connections

In this lesson students investigate the impacts of forces on wind and hydro turbines. 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.

Step 1

Conduct a quick live demonstration using a toy car, a ramp, and different weights. Show how applying different forces and weights affects the distance the car travels. Highlight the concepts of balanced and unbalanced forces.

Extension opportunity: For students requiring extension, you might like to task them with calculating the speed the different cars travel in this demonstration, comparing the findings for each different mass.

If you don’t have the materials required to conduct the demonstrations, you can show your class the image below on the attached Visual Explainer and talk through how far the car might go in each of the examples.

Suggested response: If all the forces acting on an object cancel each other out, the object remains at rest or moves at a constant speed. For the toy cars on the ramp, balanced forces would mean that gravity pulling the car down the ramp is equal to the friction or resistance pushing against it. If the forces do not cancel each other out, the object will accelerate in the direction of the unbalanced force. In this case, if gravity is stronger than friction, the car will accelerate down the ramp. This means the heaviest car is likely to go the furthest because it experiences a stronger unbalanced force due to its mass. This greater force enables it to overcome friction more effectively than the lighter cars. Therefore, it will accelerate more and travel further down the ramp.

If your students need a refresher, you can also show them this short video about balanced and unbalanced Forces (youtube.com/watch?v=YyJSlcIbd-s).

Step 2

After the demonstration, ask students to brainstorm how similar forces might affect large-scale objects like wind turbines and hydro turbines. You might like to show the images on the next slide of the Visual Explainer to prompt their thinking.

Step 3

Using the next slides of the Visual Explainer, you can show how wind and hydro turbines encounter balanced and unbalanced forces.

For wind turbines, the wind (unbalanced force) causes the turbine to spin and gravity (balanced force) helps to keep the turbines in place. For hydro turbines, you can show how gravity (unbalanced force) moves the water down through the channel while friction in the turbine counters the water pressure (balanced force).

Find Out: Investigating forces through experiments

Step 1

Explain to the students that they will be conducting an experiment to investigate how different forces affect the operation of wind and hydro turbines. This activity will help them understand the principles of balanced and unbalanced forces and their impact on motion and efficiency.

If you have access to a model turbine, you can use it for this demonstration of forces. If not, you can pre-construct a DIY wind or hydro turbine.

Demonstrate the process of measuring the forces on the turbine. If you have a wind turbine, first demonstrate how the turbine turns when wind is applied. Next, attach the end of a string to the outer edge of the turbine blade and the other end to your force meter or spring balance (as shown below). Turn on your source of wind, and take a reading of the force.

Similarly, if you have a water turbine, demonstrate how the turbine turns when water is applied, then attach a string and measure the force.

If you have enough turbines, divide the class into groups and have them practise taking a reading using these turbines. If not, progress to the ‘Take Action’ stage.

Take Action: Testing turbines

Step 1

Explain to students that they will now be working in small groups to build their own wind or water turbines, with the goal of harnessing the most energy. To lead into this activity, you might like to share this Career Profile of a renewable energy engineer working in Queensland with your students.

Invite your students to read through the career profile and ask them the following questions:

What does George do as a renewable energy engineer?
What sounds cool about his role?
How does having an understanding of the forces acting on wind turbines help him to do his job?

Suggested responses: As a renewable engineer in wind, George monitors the weather at various sites and analyses wind data to plan and design wind farms, taking into account environmental impacts. Having an understanding of the forces acting on turbines means George and his team can ensure each turbine is harnessing the most amount of wind possible to ensure the wind farm is efficient and provides people with reliable, cheap energy.

Step 2

Provide groups with the DIY Wind and Hydro Turbine Creation Guide and materials to build either the hydro turbine or the wind turbine.

Both types of turbines require cutting into PET bottles with a craft knife. You could prepare the bottles beforehand to avoid students having to use the knives, or minimise the risk by providing students with a vice to hold the bottle while they cut into it.

Step 3

Once students have built their turbine, they can test the forces acting on it when in use. Explain to students how to use force meters (or alternatives) to measure the magnitude of forces acting on their turbine models. Students should explore:

changing the magnitude of the force being applied to the turbine (turning up the water flow or increasing the fan speed)
changing the direction of the force being applied to the turbine (does it work best straight on, or should it be directed to an outer edge?)
changing the distance from the source of the force to the turbine (pouring water from lower or higher, moving the fan closer or further away).

Students should record their findings in the table on the Student Worksheet.

If you have a little more time to dedicate to this task, or have students/groups requiring extension, encourage them to think about how to conduct fair and valid tests. They should set ‘control’ settings in terms of the magnitude, direction and distance of their forces in the first test and then change only 1 setting for each test, conducting 3 trials of each and calculating the average each time. If you have less time, or students requiring additional support, you might allow students to simply explore using the turbines to determine what settings produce the most amount of force without focusing on the trials.

If students are having difficulty measuring the force using a force meter or spring balance, you can instead tape a string to the turbine shaft and see how much weight the turbine can pull in each of the different tests.

Extension opportunity: Early finishers or students requiring extension should be tasked with exploring the Future Energy Jobs Guide to think about what different careers exist for designing, constructing and maintaining wind turbines.

Step 4

Have each group present their findings to the class, focusing on how varying forces affected their turbines. Discuss the findings as a class by reflecting on the following questions:

What were the optimal settings for your turbine?
What design changes could you make to your turbine to capture more energy?
What environmental and design factors would need to be considered if you were building a large-scale version of your model to capture renewable energy?

Reflection

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

What does measuring forces have to do with generating renewable energy?
How would a renewable engineer use the data you have collected today?

Measuring the Power of Wind and Water

Go to

Summary

Lesson guides and printables

In this lesson