Lesson Plan

Teaching Sequence

Work through this resource material in the following sequence:

10 minutes

Tune In: What does it mean if energy is not created or destroyed?

20 minutes

Find Out: Transfers and transformations in conventional methods of producing electricity

25 minutes

Take Action: Transfers and transformations in electricity generated from renewable resources

5 minutes

Reflection

Tune In: What does it mean if energy is not created or destroyed?

Preparation

This lesson benefits from students understanding that energy can be divided into potential and kinetic, as well as the different types of energy. If you haven’t covered this with your class, please refer to the teacher content information.

Step 1

Ask your students to ball up a piece of scrap paper and throw it across the classroom. Ask them to name what types of energy were involved in the throw. They might say the kinetic energy of their arm, the kinetic energy of the paper ball, the potential gravitational energy of the ball at its highest point and the sound energy of the paper hitting the ground.

Read the following statement to your students:

“The law of conservation of energy states that energy can neither be created nor destroyed.”

Step 2

Ask your students to throw their piece of paper again, but this time ask them to close their eyes and focus on everything that happens in the lead-up to the throw and after the paper has left their hand. You could treat this as a micro meditation by using this quiet time to think about the statement. If energy isn’t created or destroyed, where is the energy coming from, and where is it going?

Step 3

Once students have thrown with their eyes closed, get them to again state which types of energy were involved in the throw. Challenge them to think as far forward and as far back as they can. If students are a little challenged by this, fill them in on the second part of the law of conservation of energy, that “energy cannot be created or destroyed–it can only be transferred or transformed from one form to another.”

A suggested flow could be:

Solar energy of the Sun
Chemical energy produced by plants through photosynthesis
Chemical energy of the food we eat
Chemical energy our body produces to move our muscles
Kinetic mechanical energy of an arm and hand
Kinetic mechanical energy of the ball
Potential gravitational energy of the ball at its highest point
Kinetic energy as it moves to the ground
Thermal energy produced as a result of friction with the air and floor
Sound energy as it whizzes through the air and hits the ground

Your students may come up with even more additions here! As students suggest their chains of energy, discuss how we get from one type of energy to another and write their chain up on the board.

This occurs through either a TRANSFER of the same type of energy from one place to another or the TRANSFORMATION of one type of energy to another.

If your students haven’t come across this term already, define it for them and ask them to indicate at which places in the above chain there has been a transfer or a transformation. For example, a transfer occurs when kinetic energy from your hand is transferred to the ball, while a transformation may be the kinetic energy of the ball transforming into sound when it hits the ground.

Ask students to write these definitions into their Student Worksheets.

Optional

If you have a Newton's cradle hanging around in the science faculty somewhere, this would be a great time to bring it out! If you don’t have access to one, you could watch the following short video with your students and discuss how it works, what transfers and transformations are happening, and how the energy is not ‘destroyed’ as the cradle slows down–it is lost as sound and heat.

Newton’s Cradle - Incredible Science (https://www.youtube.com/watch?v=0LnbyjOyEQ8)

Find Out: Transfers and transformations in conventional methods of producing electricity

Step 1

Watch the video below with your students, which talks about why energy is not created or destroyed.

The Law of Conservation of Energy - Alliant Energy (https://www.youtube.com/watch?v=Vx0yAS2u8gI)

Ensure your students are clear on the fact that energy exists in different forms in different things, and that we can manipulate these forms of energy to transform them into something different.

Step 2

Watch the following video with your students, which explains how electricity is produced conventionally (using fossil fuels) from 1:13 minutes.

As students watch the video, ask them to pay attention to the types of energy that are present and the transfers and transformations that occur throughout the process.

Note: This lesson focuses on the transfers and transformations between different types of energy. The next lesson in this unit goes more deeply into the comparison of energy produced from fossil fuels and renewables, including the environmental impact and efficiencies of both.

Power Stations & The National Grid | Electricity | Physics | FuseSchool (https://www.youtube.com/watch?v=A4E35Akk7kM)

Step 3

In pairs, ask students to annotate the diagram of a coal power plant provided below with the following :

The energy types that exist at certain parts of the process
The transfers and transformations that are occurring as energy moves through the plant
The definitions of the types of energy present
Whether energy is lost from the system at a particular stage

Students can use the video as a source of information, or do a little research using the internet or class materials they have used previously to help them with the definitions.

https://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Coal_fired_power_plant_diagram.svg/1280px-Coal_fired_power_plant_diagram.svg.png

Suggested responses:

Energy types, transfers and transformations

Chemical energy in coal is transformed into heat energy in the furnace.
Heat energy from the furnace is transferred to water and then steam moving through pipes.
Transfer of kinetic energy from steam to kinetic energy of turbines spinning.
Kinetic energy of turbines transformed into electrical energy.
Electrical energy transferred from generator to transformer, then transmission lines.

Energy losses

Thermal energy from the furnace is lost to the surrounding environment.
Chemical energy is lost in byproducts such as CO_2.
Electrical energy transformed to heat in wires and lost to the surrounding air.

Students can talk through their processes as a class, or to another pair, to ensure everyone has added in all available transfers and transformations.

Step 4

Ask students if they think this is a good way of producing energy, and discuss their responses.

Benefits

Coal is energy dense (contains a lot of energy), which means that we can produce a large amount of electricity by burning it to power the generator.

Limitations

Chemical energy in coal comes from a finite source and is lost once it is used up.
Produces carbon dioxide as a by-product, which is a greenhouse gas and adds to the greenhouse effect.

The production of electricity comes from the turbine spinning the generator to produce electricity. Prompt students to reflect on this point by asking if we would get different ‘electricity’ if something other than coal was used to spin the generator. What other ways have they heard of producing electricity?

Explain to students that this process can come from fossil fuels or renewable sources. Ask students to define renewable and non-renewable in their own words, either in discussion or on their Student Worksheet.

Non-renewable sources like fossil fuels are energy sources that are consumed faster than they can be replaced.

Renewable sources such as wind, solar and hydro are energy sources that can be replaced or replenished faster than they are consumed.

Take Action: Transfers and transformations in electricity generated from renewable resources

Step 1

Explain to students that whether an energy source is renewable or non-renewable, we can still use its properties to produce the same electricity in the end. There are a lot of different types of renewable energy sources.

Ask students why society would be moving towards using renewable sources of energy to produce electricity rather than fossil fuels.

Burning fossil fuels contributes to climate change. It produces large amounts of carbon dioxide, which is a greenhouse gas and adds to the greenhouse effect. If students haven’t gone into much detail of the greenhouse effect before, you could watch this video with them (until 4:55 mins) that explains the process:

What is Climate Change?: Crash Course Biology #8 (youtu.be/Y1mPWVzaGQY?feature=shared)

Step 2.

In their pairs from before, invite students to focus on a particular type of renewable energy. Each of the videos below explains the source of energy and how electricity is produced from the renewable energy source.

Students have the task of answering the following questions in relation to the energy source. They could answer these questions on the Student Worksheet, or create a doc or PowerPoint to present their information.

What is the source, and why is it renewable?
How does it produce electricity?
What transfers and transformations occur during the process of converting this source into electricity?
What are the advantages of this source?
What are the limitations?
Is this source of energy being used in Australia? Where and how?

Options

If you want to take it further, these methods are a little more complex and may be suitable for students requiring extension in your class:

Hydrogen 101 - Student Energy: https://youtu.be/Kv8WT3-7ZHE?feature=shared
Nuclear 101 - Student Energy: https://youtu.be/44ovdxOvP_A?feature=shared
Biomass 101 - Student Energy: https://youtu.be/yHWcddUZ35s?feature=shared

Step 3

Students can present their findings to the rest of the class, explaining what the type of renewable energy is, the transfers and transformations that exist within the process, its advantages and limitations, and how this energy might be being used in Australia.

As students present, you may like to prompt discussion about what they notice as the differences and similarities between fossil fuel-generated electricity and renewable energy-generated electricity, and what type of energy they would like to see more of in Australia and globally.

Reflection

Students can reflect on this lesson using the Harvard Visible Thinking Routine ‘Take Note’ (slightly modified here) to summarise their learning:

What was the most important point?
What surprised or interested you the most?
What did you find challenging, puzzling or difficult to understand?
What question(s) do you have?

Energy: Transfers and Transformations in the Generation of Electricity

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