Teaching sequence

Work through this resource material in the following sequence:

10 minutes

Tune In: The power of hydro

15 minutes

Find Out: How water turbines transform kinetic energy into electricity

30 minutes

Take Action: Create and test your own model water turbine

5 minutes

Reflection

Learning intentions and success criteria

Students will:

explore how kinetic energy from water can be transformed into electricity
design, create, and test water turbine models, evaluating the efficiency of different turbine designs in generating power.

Students can:

describe how kinetic energy from water flow is turned into mechanical and electrical energy by water turbines
outline the process of how water turbines are used to create renewable energy in pumped hydro systems
design a functional model water turbine that effectively transforms kinetic energy into mechanical energy, and evaluate the efficiency of their turbine design.

Tune In: The power of hydro

Curriculum connections

In this Design and Technology lesson, students investigate how force, motion, and energy combine in pumped hydro systems by building water turbines and understanding how they generate electricity. In the Science lessons of this unit, students investigate different types of energy, transfers, and transformations in renewable energy sources, looking into the Kidston Pumped Hydro and Solar project in detail. 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.

Step 1

Watch the following video with your students, which shows the Kidston Renewable Energy Hub.

March 2018 - The Kidston Renewable Energy Hub: Renewable Energy on Tap - (https://www.youtube.com/watch?v=egBJHR6xmiw)

Step 2

Provide your students with Post-it notes. Ask students to share their responses to the video they just watched by writing down the answers to the following questions and then sticking them up on the whiteboard:

What did you see in the energy hub that you didn’t know before?
What did you understand about how the energy hub creates electricity?
What questions do you have about how the hub creates electricity?

Step 3

Discuss students' responses as a class using the following points below to guide your discussion:

The energy hub positively impacts communities by putting an old gold mine to good use and creating electricity for homes. The energy hub consists of water reservoirs, tunnels, turbines and a solar farm. During the day, power from the solar farm will pump water from the lower to the upper reservoir. In the mornings and evenings, water will be released down the tunnel to go through the turbines to generate electricity.

Highlight to students that the Kidston Project is the first pumped hydro energy storage scheme in the world to be developed in an abandoned gold mine! How’s that for sustainability and innovation! (Source: https://genexpower.com.au/250mw-kidston-pumped-storage-hydro-project/)

Extension: Show images of the Kidston Project’s construction here (https://www.mcconnelldowell.com/projects/kidston-pumped-storage-hydro)

Find Out: How water turbines turn kinetic energy into electricity

Step 1

Invite students to share any knowledge or understanding about water turbines turning kinetic energy into electricity.

Students may have learnt about this in Science. If you would like to teach this topic more holistically, you could liaise with your Science colleagues for further background about this process.

Explain that water turbines help generate hydroelectricity – a form of energy that uses the power of water movement (eg flowing over a waterfall) to turn kinetic energy into electricity.

Step 2

Write or project the process of turning kinetic energy into electricity on the whiteboard, but not in the correct order (the steps are listed below). Invite pairs to put each step in the correct order.

Summary of the process

Potential energy: water stored in a reservoir has potential energy.
Kinetic energy: when released, the water flows and gains speed, converting potential energy to kinetic energy.
Mechanical energy: the flowing water spins the turbine blades, converting kinetic energy to mechanical energy.
Electrical energy: the generator's spinning rotor creates an electric current through electromagnetic induction, converting mechanical energy into electrical energy.

Highlight that this process of transforming kinetic energy from water into electricity is a clean and renewable way to generate power, making use of the movement of water to produce energy without harmful emissions.

Step 3

Now that students know the process of transforming kinetic energy from water into electricity, ask them if they know how a pumped hydro system works. As a class, watch this video explaining how pumped hydro works:

Pumped Hydro in Queensland - (https://www.youtube.com/watch?v=h53Vnx0XbUo&t=45s)

After watching the video, reinforce how the system works by using the following information to explain the steps of the process in more detail:

Pumped hydro renewable energy systems use the height difference in 2 water reservoirs to create a large battery. Water (and therefore energy) is stored in the higher reservoir and released when needed to create electricity. Use the image of the pumped hydro system on the attached Visual Explainer to support your explanation visually.

Upper reservoir
- The process begins with water stored in a reservoir or flowing in a river. This water has potential energy due to its height and position (think of a waterfall).

Tunnels or channels
- As the water is released, it flows down through pipes or channels, converting its potential energy into kinetic energy as it gains speed due to gravity, which pulls it down.

Propellers and turbine blades
- Show students the Water Turbine Diagram (slide 2 of Visual Explainer).
- The flowing water hits the blades of the water turbine, similar to large propellers. These blades are designed to capture the kinetic energy of the moving water.
- As water pushes against the blades, the turbine spins. The blades are connected to a rotor, which turns with the water's movement.
- The spinning rotor inside the turbine converts the kinetic energy of the moving water into mechanical energy. This rotational energy is what drives the next stage of the process.
Electricity generation
- Attached to the rotor is a generator. The generator consists of magnets and coils of wire.
- As the rotor spins, it turns the magnets inside the generator. The movement of the magnets past the coils of wire induces an electric current, a process known as electromagnetic induction.
- The mechanical energy of the spinning turbine is thus transformed into electrical energy.
Transmission of electricity
- The generated electrical energy is then transmitted through power lines to homes, businesses and other places where it is needed.
Lower reservoir
- After giving up its energy, the water flows into the lower reservoir where it is collected. This water can be pumped back up to the upper reservoir using renewable energy from solar or wind where the process can begin again.

Take Action: Create and test your own model water turbine

Step 1

Outline to students that now they have learned about how pumped hydro works, they will create their own water turbine. To do this, they need to assume different expert roles in their groups. Ask students to get into groups of 4 and ask if they know what occupations work with water turbines. You can direct them to look at the Future Jobs Guide to see if they can find an industry-related career. Otherwise, suggest the following roles (which they can look up in the guide for more information):

Mechanical Engineer – oversees the design of the turbine.
Materials Scientist – ensures the turbine materials are strong and appropriate for its function and design.
Hydrologist – oversees the water usage.
Research Analyst: records and analyses the data.

Advise groups that they will be using the following materials:

1 paper or plastic cup
1 straw
2 wooden skewers
a small cup of water or tap per group
a funnel,to create consistent water flow
a tray, bucket or sink to sit the turbine in
scissors
stopwatch (or device that has this function).

Alternatively, if you have access to a 3D printer you may want to use this technology for groups to design and print components to create their model water turbines. Ensure you follow your school’s safety protocols.

Step 2

Let students know they will all do a few things similarly, such as connecting the turbine to the shaft (base of the cup to the straw), but the rest (such as the turbine blades) will be designed and produced by them. Advise them to consider ways to optimise their turbine, such as its balance. and the size, shape, and number of blades they use.

Remind groups that, depending on their designs, the turbines may need support to sit straight on the straw (or shaft). Direct them to find a solution, as it will help their turbine spin efficiently. You may suggest cutting out another cup base to attach to the other end of the blades, or reinforcing by attaching the turbine to the shaft with sticky tape.

Step 3

Distribute 1 plastic or paper cup, 1 wooden skewer, 1 straw, sticky tape, a small jug of water, and a bucket or tray to catch the water to each group.

Step 4

Before groups begin, you may want to guide them through each step, using the How to Create a Model Water Turbine factsheet as an example.

Materials

1 paper or plastic cup
1 straw
2 wooden skewers
sticky tape
scissors

To make the base of the turbine, use scissors to cut the base out of the cup, leaving a 10-20mm lip, and place a hole in the middle of the base for the straw to fit through.

Cut 6-8 turbine blades. (This is where students can get creative. They may want to start with basic blades and then redesign them as they test their models, or think about what design would be the most efficient from the start).

Attach the turbine blades to the lip of the cup base with sticky tape.

Attach a little flag with the letter ‘R’ on one end of the straw. (This is used so that students can count the number of revolutions they see the flag do as they test it).

Fit the straw through the hole you made in the cup base.

Put the skewer through the straw (the skewer is what will be held by the tester to allow the turbine to spin freely).

Step 5

Once groups have constructed their turbines, students should work together to use and test them.

One student holds the turbine by the skewer so the straw can rotate freely over the sink, tray or bucket of water.
One student slowly pours the water out of the jug.
One student counts the revolutions by counting how many times the ‘R’ flag turns
One student times 60 seconds on a stopwatch.

When testing the turbines, consider controls such as tipping the same amount of water at the same angle through a funnel, to ensure the water flow is consistent. Ensure students use the same amount of water in each test so they can compare their designs. There is also space on the Student Worksheet for students to run 3 trials for each iteration of the turbine they test, working out a more accurate average efficiency of each design.

Learning support:

Explain that efficiency in this task is defined as generating the most rotations with the least amount of water. Other efficiency considerations could also include the amount of time spent creating iterations of the model water turbine, how much waste is generated, or the materials used in the process (eg multiple turbines vs. only 1 carefully designed turbine).
Remind students how to calculate an average (the total of the numbers in a set divided by the count of those numbers). For example, 5 + 7 + 6 =18, divided by 3 (because there are 3 counts) = 6.

Step 6

Ask students to record on their Student Worksheet the number of revolutions their turbine makes in 60 seconds. Encourage students to observe what happens when the water flow is increased or decreased. Discuss their recordings as a class so students can see how other people's designs are faring.

Ask students to consider how changing the angle or number of blades might affect the turbine’s efficiency.

Step 7

Encourage your students to experiment with blade design (such as changing their blades' size and shape or cutting folds) to make the turbines as efficient as possible, and recording more revolutions per minute.

You may like to host a little competition between groups to see who can engineer the most effective and efficient turbine.

Reflection

Ask groups to discuss and record their answers to the following questions on their Student Worksheet about the design and efficiency of their water turbine creation.

Describe how your group improved the efficiency of your turbine.
Explain how this type of energy can sustainably power communities now and in the future.
Why is blade design so important when designing turbines?
What impact does creating and testing turbines have on projects like the Kidston Hydro Project?
Identify a role that would be part of building, designing, or assessing water turbine performance.

Investigating How Turbines Create Electricity

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Lesson Guides and Printables

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Investigating How Turbines Create Electricity

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Summary

Lesson Guides and Printables

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