Australia consumes over 220,000 GWh of electricity annually — enough to power more than 30 million average homes. Every kick of a football, every lightning strike over the Blue Mountains, and every charge of your phone has something in common: energy is being transferred and transformed. In this unit you will evaluate how we use energy, where it comes from, and what that means for Australia's future.
A professional AFL player burns through roughly 1,500 kilojoules every hour on the field — about the same energy as running a toaster continuously for 25 minutes. Where does that energy come from, where does it go, and why can't the player just keep going forever?
Before reading on, estimate how many different forms of energy are involved from the moment the player eats breakfast to the moment they kick the ball. Write your estimate and list each form you think is involved — you will verify your prediction at the end of the lesson.
📚 Core Content
Wrong: "Energy is used up and disappears."
Right: Energy is conserved — it cannot be created or destroyed, only transferred or transformed. What "runs out" is useful energy, not energy itself.
Wrong: "Energy and force are the same thing."
Right: Force is a push or pull. Energy is the capacity to do work. A force can transfer energy, but they are different concepts.
If you can name a process — any process — energy is involved. The question is never "is there energy?" but rather "what form is it in, and how is it changing?"
Energy is not a physical substance you can hold. It is a property that objects and systems possess. A moving cricket ball has kinetic energy. A battery on a shelf has chemical potential energy. The Sun emits light energy. A stretched bowstring has elastic potential energy.
In Stage 5 Science, the most important forms to recognise are:
Students often use "transfer" and "transform" interchangeably. In science, they mean different things — and confusing them costs marks in assessments.
An energy transfer is when energy moves from one place to another without changing form. When you touch a hot saucepan, thermal energy transfers from the metal to your hand. It is still thermal energy — just in a different place.
An energy transformation is when energy changes from one form to another. When you turn on a torch, chemical energy in the battery transforms into electrical energy, which then transforms into light and thermal energy in the bulb.
Most real processes involve both. A car engine transforms chemical energy in petrol into thermal energy, then into kinetic energy of the wheels, while some thermal energy transfers to the surrounding air through the exhaust and radiator.
Energy is not just a physics idea. It is the foundation of modern life. Every decision about energy — where it comes from, how it is used, who has access to it — has consequences that reach far beyond a science classroom.
Australia's energy mix is changing rapidly. Coal-fired power stations like Liddell in New South Wales have closed, while solar and wind capacity has grown faster than in almost any other developed nation. In 2023, renewable sources provided over 35% of Australia's electricity generation, up from just 8% in 2008.
But the transition is not simple. Energy must be reliable as well as clean. When the sun does not shine and the wind does not blow, something else must provide power. This is why batteries, pumped hydro storage, and demand management are now central to Australia's energy planning.
The red kangaroo is one of the most energy-efficient large animals on Earth. Its long elastic tendons store gravitational potential energy on each landing and release it on the next hop, meaning kangaroos actually use less energy per metre at high speeds than at low speeds. At 25 km/h, a kangaroo's oxygen consumption is about half what a similarly sized dog would need.
An elite AFL midfielder runs approximately 14 kilometres per game, with about 3 kilometres at high intensity. Over four quarters, that player transforms roughly 6,000 kilojoules of chemical energy from food into kinetic energy, thermal energy (sweating), and sound energy (calls, collisions). Understanding energy helps coaches design training programs, nutrition plans, and recovery schedules.
These are all common in Australian life. Click to check your prediction.
1 The Sun warming the sand
2 A surfer paddling (chemical energy in muscles → movement)
3 The quad bike engine running on petrol
4 The seagull's call reaching your ears
5 The portable solar panel charging the phone
1. Which statement best describes the difference between an energy transfer and an energy transformation?
2. A student says: "When I ride my bike downhill, gravitational potential energy transforms into kinetic energy." Is this correct?
3. A coal-fired power station in the Latrobe Valley burns coal to generate electricity for Melbourne. Which energy chain is most accurate?
4. Why is the statement "energy is used up" scientifically incorrect?
5. In 2023, renewable energy provided over 35% of Australia's electricity. Which factor is the greatest challenge for increasing this percentage further?
6. Define energy transfer and energy transformation. Give one clear example of each. 1 mark for correct definition of transfer. 1 mark for correct definition of transformation. 1 mark for one valid example of each.
7. A wind turbine at the Hornsdale Wind Farm in South Australia generates electricity. Describe the energy transformations that occur from the moving air to the electrical energy in a home. 1 mark for kinetic energy of wind. 1 mark for kinetic energy of turbine blades. 1 mark for generator converting to electrical energy. 1 mark for transfer through power lines.
8. Evaluate this statement: "Australia should stop using coal immediately and rely only on solar and wind energy." Use scientific evidence about energy sources, reliability, and at least one Australian example in your answer. 1 mark for identifying a valid argument for the statement. 1 mark for identifying a valid argument against the statement. 1 mark for using scientific evidence about reliability. 1 mark for an Australian example. 1 mark for a balanced, evidence-based conclusion.
1. The Sun warming the sand: Light energy from the Sun transfers to the sand as thermal energy. This is an energy transfer (light → thermal) and also a transformation because the form changes. The thermal energy then transfers through the sand by conduction.
2. Surfer paddling: Chemical energy in the surfer's muscle cells transforms into kinetic energy of the arms and board, and some thermal energy (the surfer gets warmer). This is primarily an energy transformation.
3. Quad bike engine: Chemical energy in petrol transforms into thermal energy during combustion, then into kinetic energy of the engine parts and wheels. Some thermal energy transfers to the air through the exhaust. Multiple transformations occur.
4. Seagull's call: Chemical energy in the bird's muscles transforms into kinetic energy of the syrinx (voice box), which creates sound energy that travels through the air to your ears. The sound energy is transferred through the air as vibrations.
5. Solar panel charging phone: Light energy from the Sun transforms into electrical energy in the solar panel. The electrical energy is transferred through wires to the phone, where it transforms into chemical energy stored in the battery.
Step 1: The Sun emits light energy (and other electromagnetic radiation).
Step 2: At the solar farm, photovoltaic cells transform light energy → electrical energy.
Step 3: Electrical energy is transferred through high-voltage transmission lines and local distribution wires from the solar farm to the student's home in Sydney.
Step 4: In the kettle's heating element, electrical energy → thermal energy as electrons collide with metal atoms, increasing their vibration.
Step 5: Thermal energy is transferred from the element to the water by conduction and convection, raising the water temperature.
1. C — Transfer = same form, different place. Transformation = one form becomes another. Option A reverses the definitions. Option B is incorrect — they are distinct concepts. Option D is wrong — both living things and machines can do both.
2. B — As the bike loses height, gravitational potential energy (stored energy due to position) decreases and kinetic energy (energy of motion) increases. This is a direct transformation. Option A is false — potential energy can absolutely become kinetic. Option C confuses transfer with transformation. Option D incorrectly adds an unnecessary condition.
3. D — Coal stores chemical energy. Burning transforms chemical → thermal. The thermal energy heats water to produce steam, whose kinetic energy spins turbines. The turbines spin generators that transform kinetic → electrical. Option A has the wrong order. Option B starts with thermal, which is wrong. Option C starts with kinetic, which is wrong.
4. A — The law of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed. What "runs out" is useful energy — some energy always becomes waste thermal energy that is difficult to capture. Option B violates conservation of energy. Option C is false. Option D contradicts a fundamental law of physics.
5. C — Intermittency is the well-documented scientific and engineering challenge for solar and wind. When these sources are unavailable, demand must be met by storage (batteries, pumped hydro) or backup generation. Option A is false — Australia has excellent solar resources. Option B is misleading — while costs exist, they are not the primary challenge. Option D is unsupported by evidence — polling consistently shows majority Australian support for renewables.
Q6 (3 marks): Energy transfer is when energy moves from one place to another without changing its form [1 mark]. For example, thermal energy transferring from a hot stove to a pot [0.5 mark]. Energy transformation is when energy changes from one form to another [1 mark]. For example, chemical energy in a battery transforming into electrical energy [0.5 mark].
Q7 (4 marks): Step 1: Wind has kinetic energy [1 mark]. Step 2: The wind pushes the turbine blades, giving them kinetic energy [1 mark]. Step 3: The spinning blades turn a generator, transforming kinetic energy into electrical energy [1 mark]. Step 4: The electrical energy is transferred through transmission lines to homes [1 mark].
Q8 (5 marks): Arguments for: Coal combustion releases CO₂, a greenhouse gas that contributes to climate change. Australia has excellent solar and wind resources. The cost of renewables has fallen dramatically [1 mark]. Arguments against: Solar and wind are intermittent — they do not generate when the sun is down or wind is calm. Sudden coal closure could cause blackouts and job losses in coal-dependent communities like the Latrobe Valley [1 mark]. Scientific evidence: Grid reliability requires supply to match demand every second. Without sufficient storage (batteries, pumped hydro) or backup, a grid relying only on solar and wind would be unstable [1 mark]. Australian example: The Hornsdale Power Reserve (Tesla Big Battery) in South Australia provides grid stability services, demonstrating that storage can help address intermittency, but at significant cost and scale [1 mark]. Conclusion: A rapid transition away from coal is scientifically and environmentally desirable, but it must be managed with investment in storage, grid infrastructure, and community support to maintain reliability and equity [1 mark].
Want to review any section before moving on?
Tick when you have finished all activities, checked your answers, and can identify energy forms, transfers and transformations.